From 84f206ca83def76f42b8eeb247fbd283a053e5cf Mon Sep 17 00:00:00 2001
From: root <root@eriri.sawamura>
Date: Tue, 28 May 2019 17:20:41 +0800
Subject: [PATCH] Edit button for posts and comments

---
 footer.php                                    |    2 +-
 functions.php                                 |   14 +
 inc/scssphp--old/LICENSE.md                   |   20 -
 inc/scssphp--old/README.md                    |   47 -
 inc/scssphp--old/bin/pscss                    |  215 -
 inc/scssphp--old/composer.json                |   41 -
 inc/scssphp--old/example/Server.php           |  517 --
 inc/scssphp--old/scss.inc.php                 |   32 -
 inc/scssphp--old/src/Base/Range.php           |   47 -
 inc/scssphp--old/src/Block.php                |   65 -
 inc/scssphp--old/src/Colors.php               |  179 -
 inc/scssphp--old/src/Compiler.php             | 5336 -----------------
 inc/scssphp--old/src/Compiler/Environment.php |   40 -
 .../src/Exception/CompilerException.php       |   21 -
 .../src/Exception/ParserException.php         |   21 -
 .../src/Exception/RangeException.php          |   21 -
 .../src/Exception/ServerException.php         |   21 -
 inc/scssphp--old/src/Formatter.php            |  274 -
 inc/scssphp--old/src/Formatter/Compact.php    |   45 -
 inc/scssphp--old/src/Formatter/Compressed.php |   62 -
 inc/scssphp--old/src/Formatter/Crunched.php   |   60 -
 inc/scssphp--old/src/Formatter/Debug.php      |  121 -
 inc/scssphp--old/src/Formatter/Expanded.php   |   68 -
 inc/scssphp--old/src/Formatter/Nested.php     |  201 -
 .../src/Formatter/OutputBlock.php             |   65 -
 inc/scssphp--old/src/Node.php                 |   40 -
 inc/scssphp--old/src/Node/Number.php          |  330 -
 inc/scssphp--old/src/Parser.php               | 2494 --------
 .../src/SourceMap/Base64VLQEncoder.php        |  217 -
 .../src/SourceMap/SourceMapGenerator.php      |  337 --
 inc/scssphp--old/src/Type.php                 |   69 -
 inc/scssphp--old/src/Util.php                 |   70 -
 inc/scssphp--old/src/Version.php              |   22 -
 inc/theme_plus.php                            |    8 +-
 options.php                                   |   14 +-
 35 files changed, 29 insertions(+), 11107 deletions(-)
 delete mode 100644 inc/scssphp--old/LICENSE.md
 delete mode 100644 inc/scssphp--old/README.md
 delete mode 100644 inc/scssphp--old/bin/pscss
 delete mode 100644 inc/scssphp--old/composer.json
 delete mode 100644 inc/scssphp--old/example/Server.php
 delete mode 100644 inc/scssphp--old/scss.inc.php
 delete mode 100644 inc/scssphp--old/src/Base/Range.php
 delete mode 100644 inc/scssphp--old/src/Block.php
 delete mode 100644 inc/scssphp--old/src/Colors.php
 delete mode 100644 inc/scssphp--old/src/Compiler.php
 delete mode 100644 inc/scssphp--old/src/Compiler/Environment.php
 delete mode 100644 inc/scssphp--old/src/Exception/CompilerException.php
 delete mode 100644 inc/scssphp--old/src/Exception/ParserException.php
 delete mode 100644 inc/scssphp--old/src/Exception/RangeException.php
 delete mode 100644 inc/scssphp--old/src/Exception/ServerException.php
 delete mode 100644 inc/scssphp--old/src/Formatter.php
 delete mode 100644 inc/scssphp--old/src/Formatter/Compact.php
 delete mode 100644 inc/scssphp--old/src/Formatter/Compressed.php
 delete mode 100644 inc/scssphp--old/src/Formatter/Crunched.php
 delete mode 100644 inc/scssphp--old/src/Formatter/Debug.php
 delete mode 100644 inc/scssphp--old/src/Formatter/Expanded.php
 delete mode 100644 inc/scssphp--old/src/Formatter/Nested.php
 delete mode 100644 inc/scssphp--old/src/Formatter/OutputBlock.php
 delete mode 100644 inc/scssphp--old/src/Node.php
 delete mode 100644 inc/scssphp--old/src/Node/Number.php
 delete mode 100644 inc/scssphp--old/src/Parser.php
 delete mode 100644 inc/scssphp--old/src/SourceMap/Base64VLQEncoder.php
 delete mode 100644 inc/scssphp--old/src/SourceMap/SourceMapGenerator.php
 delete mode 100644 inc/scssphp--old/src/Type.php
 delete mode 100644 inc/scssphp--old/src/Util.php
 delete mode 100644 inc/scssphp--old/src/Version.php

diff --git a/footer.php b/footer.php
index ada9b28..6f23ce5 100644
--- a/footer.php
+++ b/footer.php
@@ -20,7 +20,7 @@
 	?>
 	</div><!-- #page Pjax container-->
 	<footer id="colophon" class="site-footer" role="contentinfo">
-		<div class="site-info">
+		<div class="site-info" theme-info="Sakura v<?php echo SAKURA_VERSION; ?>">
 			<div class="footertext">
 				<div class="img-preload">
 					<img src="https://cdn.jsdelivr.net/gh/moezx/cdn@3.1.9/img/Sakura/images/wordpress-rotating-ball-o.svg">
diff --git a/functions.php b/functions.php
index 15f062d..267d346 100644
--- a/functions.php
+++ b/functions.php
@@ -398,6 +398,7 @@ if(!function_exists('akina_comment_format')){
                                                 $flag .= '否 <i class="fa fa-unlock" aria-hidden="true"></i>';
                                             }
                                             $flag .= '</span>)</a>';
+                                            $flag .= edit_comment_link(__('<i class="fa fa-pencil-square-o" aria-hidden="true"></i> 编辑'), '<span>', '</span>');
                                             echo $flag;
                                         } ?></div>
 								</div>
@@ -1430,6 +1431,19 @@ dash_scheme($key="custom", $name="Custom",
             $base=akina_option('dash_scheme_color_base'), $focus=akina_option('dash_scheme_color_focus'), $current=akina_option('dash_scheme_color_current'),
             $rules=akina_option('dash_scheme_css_rules'));
 
+//Set Default Admin Color Scheme for New Users
+function set_default_admin_color($user_id) {
+    $args = array(
+        'ID' => $user_id,
+        'admin_color' => 'sunrise'
+    );
+    wp_update_user( $args );
+}
+//add_action('user_register', 'set_default_admin_color');            
+
+//Stop Users From Switching Admin Color Schemes
+//if ( !current_user_can('manage_options') ) remove_action( 'admin_color_scheme_picker', 'admin_color_scheme_picker' );
+
 // WordPress Custom Font @ Admin
 function custom_admin_open_sans_font() {
     echo '<link href="https://fonts.googleapis.com/css?family=Noto+Serif+SC&display=swap" rel="stylesheet">' . PHP_EOL;
diff --git a/inc/scssphp--old/LICENSE.md b/inc/scssphp--old/LICENSE.md
deleted file mode 100644
index 2f5412f..0000000
--- a/inc/scssphp--old/LICENSE.md
+++ /dev/null
@@ -1,20 +0,0 @@
-Copyright (c) 2015 Leaf Corcoran, http://leafo.github.io/scssphp
- 
-Permission is hereby granted, free of charge, to any person obtaining
-a copy of this software and associated documentation files (the
-"Software"), to deal in the Software without restriction, including
-without limitation the rights to use, copy, modify, merge, publish,
-distribute, sublicense, and/or sell copies of the Software, and to
-permit persons to whom the Software is furnished to do so, subject to
-the following conditions:
- 
-The above copyright notice and this permission notice shall be
-included in all copies or substantial portions of the Software.
- 
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
-LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
-OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
-WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/inc/scssphp--old/README.md b/inc/scssphp--old/README.md
deleted file mode 100644
index 53a4c7a..0000000
--- a/inc/scssphp--old/README.md
+++ /dev/null
@@ -1,47 +0,0 @@
-# scssphp
-### <http://leafo.github.io/scssphp>
-
-[![Build](https://travis-ci.org/leafo/scssphp.svg?branch=master)](http://travis-ci.org/leafo/scssphp)
-[![License](https://poser.pugx.org/leafo/scssphp/license.svg)](https://packagist.org/packages/leafo/scssphp)
-
-`scssphp` is a compiler for SCSS written in PHP.
-
-Checkout the homepage, <http://leafo.github.io/scssphp>, for directions on how to use.
-
-## Running Tests
-
-`scssphp` uses [PHPUnit](https://github.com/sebastianbergmann/phpunit) for testing.
-
-Run the following command from the root directory to run every test:
-
-    vendor/bin/phpunit tests
-
-There are several tests in the `tests/` directory:
-
-* `ApiTest.php` contains various unit tests that test the PHP interface.
-* `ExceptionTest.php` contains unit tests that test for exceptions thrown by the parser and compiler.
-* `FailingTest.php` contains tests reported in Github issues that demonstrate compatibility bugs.
-* `InputTest.php` compiles every `.scss` file in the `tests/inputs` directory
-  then compares to the respective `.css` file in the `tests/outputs` directory.
-* `ScssTest.php` extracts (ruby) `scss` tests from the `tests/scss_test.rb` file.
-* `ServerTest.php` contains functional tests for the `Server` class.
-
-When changing any of the tests in `tests/inputs`, the tests will most likely
-fail because the output has changed. Once you verify that the output is correct
-you can run the following command to rebuild all the tests:
-
-    BUILD=1 vendor/bin/phpunit tests
-
-This will compile all the tests, and save results into `tests/outputs`.
-
-To enable the `scss` compatibility tests:
-
-    TEST_SCSS_COMPAT=1 vendor/bin/phpunit tests
-
-## Coding Standard
-
-`scssphp` source conforms to [PSR2](http://www.php-fig.org/psr/psr-2/).
-
-Run the following command from the root directory to check the code for "sniffs".
-
-    vendor/bin/phpcs --standard=PSR2 bin src tests
diff --git a/inc/scssphp--old/bin/pscss b/inc/scssphp--old/bin/pscss
deleted file mode 100644
index be1cb51..0000000
--- a/inc/scssphp--old/bin/pscss
+++ /dev/null
@@ -1,215 +0,0 @@
-#!/usr/bin/env php
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2015 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-error_reporting(E_ALL);
-
-if (version_compare(PHP_VERSION, '5.4') < 0) {
-    die('Requires PHP 5.4 or above');
-}
-
-include __DIR__ . '/../scss.inc.php';
-
-use Leafo\ScssPhp\Compiler;
-use Leafo\ScssPhp\Parser;
-use Leafo\ScssPhp\Version;
-
-$style = null;
-$loadPaths = null;
-$precision = null;
-$dumpTree = false;
-$inputFile = null;
-$changeDir = false;
-$debugInfo = false;
-$lineNumbers = false;
-$ignoreErrors = false;
-$encoding = false;
-$sourceMap = false;
-
-/**
- * Parse argument
- *
- * @param integer $i
- * @param array $options
- *
- * @return string|null
- */
-function parseArgument(&$i, $options) {
-    global $argc;
-    global $argv;
-
-    if (! preg_match('/^(?:' . implode('|', (array) $options) . ')=?(.*)/', $argv[$i], $matches)) {
-        return;
-    }
-
-    if (strlen($matches[1])) {
-        return $matches[1];
-    }
-
-    if ($i + 1 < $argc) {
-        $i++;
-
-        return $argv[$i];
-    }
-}
-
-for ($i = 1; $i < $argc; $i++) {
-    if ($argv[$i] === '-h' || $argv[$i] === '--help') {
-        $exe = $argv[0];
-
-        $HELP = <<<EOT
-Usage: $exe [options] [input-file]
-
-Options include:
-
-    -h, --help          Show this message
-    --continue-on-error Continue compilation (as best as possible) when error encountered
-    --debug-info        Annotate selectors with CSS referring to the source file and line number
-    -f=format           Set the output format (compact, compressed, crunched, expanded, or nested)
-    -i=path             Set import path
-    --iso8859-1         Use iso8859-1 encoding instead of utf-8 (default utf-8)
-    --line-numbers      Annotate selectors with comments referring to the source file and line number
-    -p=precision        Set decimal number precision (default 10)
-    --sourcemap         Create source map file
-    -T                  Dump formatted parse tree
-    -v, --version       Print the version
-
-EOT;
-        exit($HELP);
-    }
-
-    if ($argv[$i] === '-v' || $argv[$i] === '--version') {
-        exit(Version::VERSION . "\n");
-    }
-
-    if ($argv[$i] === '--continue-on-error') {
-        $ignoreErrors = true;
-        continue;
-    }
-
-    if ($argv[$i] === '--debug-info') {
-        $debugInfo = true;
-        continue;
-    }
-
-    if ($argv[$i] === '--iso8859-1') {
-        $encoding = 'iso8859-1';
-        continue;
-    }
-
-    if ($argv[$i] === '--line-numbers' || $argv[$i] === '--line-comments') {
-        $lineNumbers = true;
-        continue;
-    }
-
-    if ($argv[$i] === '--sourcemap') {
-        $sourceMap = true;
-        continue;
-    }
-
-    if ($argv[$i] === '-T') {
-        $dumpTree = true;
-        continue;
-    }
-
-    $value = parseArgument($i, array('-f', '--style'));
-
-    if (isset($value)) {
-        $style = $value;
-        continue;
-    }
-
-    $value = parseArgument($i, array('-i', '--load_paths'));
-
-    if (isset($value)) {
-        $loadPaths = $value;
-        continue;
-    }
-
-    $value = parseArgument($i, array('-p', '--precision'));
-
-    if (isset($value)) {
-        $precision = $value;
-        continue;
-    }
-
-    if (file_exists($argv[$i])) {
-        $inputFile = $argv[$i];
-        continue;
-    }
-}
-
-
-if ($inputFile) {
-    $data = file_get_contents($inputFile);
-
-    $newWorkingDir = dirname(realpath($inputFile));
-    $oldWorkingDir = getcwd();
-
-    if ($oldWorkingDir !== $newWorkingDir) {
-        $changeDir = chdir($newWorkingDir);
-        $inputFile = basename($inputFile);
-    }
-} else {
-    $data = '';
-
-    while (! feof(STDIN)) {
-        $data .= fread(STDIN, 8192);
-    }
-}
-
-if ($dumpTree) {
-    $parser = new Parser($inputFile);
-
-    print_r(json_decode(json_encode($parser->parse($data)), true));
-
-    exit();
-}
-
-$scss = new Compiler();
-
-if ($debugInfo) {
-    $scss->setLineNumberStyle(Compiler::DEBUG_INFO);
-}
-
-if ($lineNumbers) {
-    $scss->setLineNumberStyle(Compiler::LINE_COMMENTS);
-}
-
-if ($ignoreErrors) {
-    $scss->setIgnoreErrors($ignoreErrors);
-}
-
-if ($loadPaths) {
-    $scss->setImportPaths(explode(PATH_SEPARATOR, $loadPaths));
-}
-
-if ($precision) {
-    $scss->setNumberPrecision($precision);
-}
-
-if ($style) {
-    $scss->setFormatter('Leafo\\ScssPhp\\Formatter\\' . ucfirst($style));
-}
-
-if ($sourceMap) {
-    $scss->setSourceMap(Compiler::SOURCE_MAP_FILE);
-}
-
-if ($encoding) {
-    $scss->setEncoding($encoding);
-}
-
-echo $scss->compile($data, $inputFile);
-
-if ($changeDir) {
-    chdir($oldWorkingDir);
-}
diff --git a/inc/scssphp--old/composer.json b/inc/scssphp--old/composer.json
deleted file mode 100644
index 95118a3..0000000
--- a/inc/scssphp--old/composer.json
+++ /dev/null
@@ -1,41 +0,0 @@
-{
-    "name": "leafo/scssphp",
-    "type": "library",
-    "description": "scssphp is a compiler for SCSS written in PHP.",
-    "keywords": ["css", "stylesheet", "scss", "sass", "less"],
-    "homepage": "http://leafo.github.io/scssphp/",
-    "license": [
-        "MIT"
-    ],
-    "authors": [
-        {
-            "name": "Leaf Corcoran",
-            "email": "leafot@gmail.com",
-            "homepage": "http://leafo.net"
-        }
-    ],
-    "autoload": {
-        "psr-4": { "Leafo\\ScssPhp\\": "src/" }
-    },
-    "autoload-dev": {
-        "psr-4": { "Leafo\\ScssPhp\\Test\\": "tests/" }
-    },
-    "require": {
-        "php": ">=5.4.0"
-    },
-    "require-dev": {
-        "squizlabs/php_codesniffer": "~2.5",
-        "phpunit/phpunit": "~4.6"
-    },
-    "bin": ["bin/pscss"],
-    "archive": {
-        "exclude": [
-            "/Makefile",
-            "/.gitattributes",
-            "/.gitignore",
-            "/.travis.yml",
-            "/phpunit.xml.dist",
-            "/tests"
-        ]
-    }
-}
diff --git a/inc/scssphp--old/example/Server.php b/inc/scssphp--old/example/Server.php
deleted file mode 100644
index a8dc045..0000000
--- a/inc/scssphp--old/example/Server.php
+++ /dev/null
@@ -1,517 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2017 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp;
-
-use Leafo\ScssPhp\Compiler;
-use Leafo\ScssPhp\Exception\ServerException;
-use Leafo\ScssPhp\Version;
-
-/**
- * Server
- *
- * @author Leaf Corcoran <leafot@gmail.com>
- */
-class Server
-{
-    /**
-     * @var boolean
-     */
-    private $showErrorsAsCSS;
-
-    /**
-     * @var string
-     */
-    private $dir;
-
-    /**
-     * @var string
-     */
-    private $cacheDir;
-
-    /**
-     * @var \Leafo\ScssPhp\Compiler
-     */
-    private $scss;
-
-    /**
-     * Join path components
-     *
-     * @param string $left  Path component, left of the directory separator
-     * @param string $right Path component, right of the directory separator
-     *
-     * @return string
-     */
-    protected function join($left, $right)
-    {
-        return rtrim($left, '/\\') . DIRECTORY_SEPARATOR . ltrim($right, '/\\');
-    }
-
-    /**
-     * Get name of requested .scss file
-     *
-     * @return string|null
-     */
-    protected function inputName()
-    {
-        switch (true) {
-            case isset($_GET['p']):
-                return $_GET['p'];
-            case isset($_SERVER['PATH_INFO']):
-                return $_SERVER['PATH_INFO'];
-            case isset($_SERVER['DOCUMENT_URI']):
-                return substr($_SERVER['DOCUMENT_URI'], strlen($_SERVER['SCRIPT_NAME']));
-        }
-    }
-
-    /**
-     * Get path to requested .scss file
-     *
-     * @return string
-     */
-    protected function findInput()
-    {
-        if (($input = $this->inputName())
-            && strpos($input, '..') === false
-            && substr($input, -5) === '.scss'
-        ) {
-            $name = $this->join($this->dir, $input);
-
-            if (is_file($name) && is_readable($name)) {
-                return $name;
-            }
-        }
-
-        return false;
-    }
-
-    /**
-     * Get path to cached .css file
-     *
-     * @return string
-     */
-    protected function cacheName($fname)
-    {
-        return $this->join($this->cacheDir, md5($fname) . '.css');
-    }
-
-    /**
-     * Get path to meta data
-     *
-     * @return string
-     */
-    protected function metadataName($out)
-    {
-        return $out . '.meta';
-    }
-
-    /**
-     * Determine whether .scss file needs to be re-compiled.
-     *
-     * @param string $out  Output path
-     * @param string $etag ETag
-     *
-     * @return boolean True if compile required.
-     */
-    protected function needsCompile($out, &$etag)
-    {
-        if (! is_file($out)) {
-            return true;
-        }
-
-        $mtime = filemtime($out);
-
-        $metadataName = $this->metadataName($out);
-
-        if (is_readable($metadataName)) {
-            $metadata = unserialize(file_get_contents($metadataName));
-
-            foreach ($metadata['imports'] as $import => $originalMtime) {
-                $currentMtime = filemtime($import);
-
-                if ($currentMtime !== $originalMtime || $currentMtime > $mtime) {
-                    return true;
-                }
-            }
-
-            $metaVars = crc32(serialize($this->scss->getVariables()));
-
-            if ($metaVars !== $metadata['vars']) {
-                return true;
-            }
-
-            $etag = $metadata['etag'];
-
-            return false;
-        }
-
-        return true;
-    }
-
-    /**
-     * Get If-Modified-Since header from client request
-     *
-     * @return string|null
-     */
-    protected function getIfModifiedSinceHeader()
-    {
-        $modifiedSince = null;
-
-        if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
-            $modifiedSince = $_SERVER['HTTP_IF_MODIFIED_SINCE'];
-
-            if (false !== ($semicolonPos = strpos($modifiedSince, ';'))) {
-                $modifiedSince = substr($modifiedSince, 0, $semicolonPos);
-            }
-        }
-
-        return $modifiedSince;
-    }
-
-    /**
-     * Get If-None-Match header from client request
-     *
-     * @return string|null
-     */
-    protected function getIfNoneMatchHeader()
-    {
-        $noneMatch = null;
-
-        if (isset($_SERVER['HTTP_IF_NONE_MATCH'])) {
-            $noneMatch = $_SERVER['HTTP_IF_NONE_MATCH'];
-        }
-
-        return $noneMatch;
-    }
-
-    /**
-     * Compile .scss file
-     *
-     * @param string $in  Input path (.scss)
-     * @param string $out Output path (.css)
-     *
-     * @return array
-     */
-    protected function compile($in, $out)
-    {
-        $start   = microtime(true);
-        $css     = $this->scss->compile(file_get_contents($in), $in);
-        $elapsed = round((microtime(true) - $start), 4);
-
-        $v    = Version::VERSION;
-        $t    = date('r');
-        $css  = "/* compiled by scssphp $v on $t (${elapsed}s) */\n\n" . $css;
-        $etag = md5($css);
-
-        file_put_contents($out, $css);
-        file_put_contents(
-            $this->metadataName($out),
-            serialize([
-                'etag'    => $etag,
-                'imports' => $this->scss->getParsedFiles(),
-                'vars'    => crc32(serialize($this->scss->getVariables())),
-            ])
-        );
-
-        return [$css, $etag];
-    }
-
-    /**
-     * Format error as a pseudo-element in CSS
-     *
-     * @param \Exception $error
-     *
-     * @return string
-     */
-    protected function createErrorCSS(\Exception $error)
-    {
-        $message = str_replace(
-            ["'", "\n"],
-            ["\\'", "\\A"],
-            $error->getfile() . ":\n\n" . $error->getMessage()
-        );
-
-        return "body { display: none !important; }
-                html:after {
-                    background: white;
-                    color: black;
-                    content: '$message';
-                    display: block !important;
-                    font-family: mono;
-                    padding: 1em;
-                    white-space: pre;
-                }";
-    }
-
-    /**
-     * Render errors as a pseudo-element within valid CSS, displaying the errors on any
-     * page that includes this CSS.
-     *
-     * @param boolean $show
-     */
-    public function showErrorsAsCSS($show = true)
-    {
-        $this->showErrorsAsCSS = $show;
-    }
-
-    /**
-     * Compile .scss file
-     *
-     * @param string $in  Input file (.scss)
-     * @param string $out Output file (.css) optional
-     *
-     * @return string|bool
-     *
-     * @throws \Leafo\ScssPhp\Exception\ServerException
-     */
-    public function compileFile($in, $out = null)
-    {
-        if (! is_readable($in)) {
-            throw new ServerException('load error: failed to find ' . $in);
-        }
-
-        $pi = pathinfo($in);
-
-        $this->scss->addImportPath($pi['dirname'] . '/');
-
-        $compiled = $this->scss->compile(file_get_contents($in), $in);
-
-        if ($out !== null) {
-            return file_put_contents($out, $compiled);
-        }
-
-        return $compiled;
-    }
-
-    /**
-     * Check if file need compiling
-     *
-     * @param string $in  Input file (.scss)
-     * @param string $out Output file (.css)
-     *
-     * @return bool
-     */
-    public function checkedCompile($in, $out)
-    {
-        if (! is_file($out) || filemtime($in) > filemtime($out)) {
-            $this->compileFile($in, $out);
-
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Compile requested scss and serve css.  Outputs HTTP response.
-     *
-     * @param string $salt Prefix a string to the filename for creating the cache name hash
-     */
-    public function serve($salt = '')
-    {
-        $protocol = isset($_SERVER['SERVER_PROTOCOL'])
-            ? $_SERVER['SERVER_PROTOCOL']
-            : 'HTTP/1.0';
-
-        if ($input = $this->findInput()) {
-            $output = $this->cacheName($salt . $input);
-            $etag = $noneMatch = trim($this->getIfNoneMatchHeader(), '"');
-
-            if ($this->needsCompile($output, $etag)) {
-                try {
-                    list($css, $etag) = $this->compile($input, $output);
-
-                    $lastModified = gmdate('D, d M Y H:i:s', filemtime($output)) . ' GMT';
-
-                    header('Last-Modified: ' . $lastModified);
-                    header('Content-type: text/css');
-                    header('ETag: "' . $etag . '"');
-
-                    echo $css;
-                } catch (\Exception $e) {
-                    if ($this->showErrorsAsCSS) {
-                        header('Content-type: text/css');
-
-                        echo $this->createErrorCSS($e);
-                    } else {
-                        header($protocol . ' 500 Internal Server Error');
-                        header('Content-type: text/plain');
-
-                        echo 'Parse error: ' . $e->getMessage() . "\n";
-                    }
-                }
-
-                return;
-            }
-
-            header('X-SCSS-Cache: true');
-            header('Content-type: text/css');
-            header('ETag: "' . $etag . '"');
-
-            if ($etag === $noneMatch) {
-                header($protocol . ' 304 Not Modified');
-
-                return;
-            }
-
-            $modifiedSince = $this->getIfModifiedSinceHeader();
-            $mtime = filemtime($output);
-
-            if (strtotime($modifiedSince) === $mtime) {
-                header($protocol . ' 304 Not Modified');
-
-                return;
-            }
-
-            $lastModified  = gmdate('D, d M Y H:i:s', $mtime) . ' GMT';
-            header('Last-Modified: ' . $lastModified);
-
-            echo file_get_contents($output);
-
-            return;
-        }
-
-        header($protocol . ' 404 Not Found');
-        header('Content-type: text/plain');
-
-        $v = Version::VERSION;
-        echo "/* INPUT NOT FOUND scss $v */\n";
-    }
-
-    /**
-     * Based on explicit input/output files does a full change check on cache before compiling.
-     *
-     * @param string  $in
-     * @param string  $out
-     * @param boolean $force
-     *
-     * @return string Compiled CSS results
-     *
-     * @throws \Leafo\ScssPhp\Exception\ServerException
-     */
-    public function checkedCachedCompile($in, $out, $force = false)
-    {
-        if (! is_file($in) || ! is_readable($in)) {
-            throw new ServerException('Invalid or unreadable input file specified.');
-        }
-
-        if (is_dir($out) || ! is_writable(file_exists($out) ? $out : dirname($out))) {
-            throw new ServerException('Invalid or unwritable output file specified.');
-        }
-
-        if ($force || $this->needsCompile($out, $etag)) {
-            list($css, $etag) = $this->compile($in, $out);
-        } else {
-            $css = file_get_contents($out);
-        }
-
-        return $css;
-    }
-
-    /**
-     * Execute scssphp on a .scss file or a scssphp cache structure
-     *
-     * The scssphp cache structure contains information about a specific
-     * scss file having been parsed. It can be used as a hint for future
-     * calls to determine whether or not a rebuild is required.
-     *
-     * The cache structure contains two important keys that may be used
-     * externally:
-     *
-     * compiled: The final compiled CSS
-     * updated: The time (in seconds) the CSS was last compiled
-     *
-     * The cache structure is a plain-ol' PHP associative array and can
-     * be serialized and unserialized without a hitch.
-     *
-     * @param mixed   $in    Input
-     * @param boolean $force Force rebuild?
-     *
-     * @return array scssphp cache structure
-     */
-    public function cachedCompile($in, $force = false)
-    {
-        // assume no root
-        $root = null;
-
-        if (is_string($in)) {
-            $root = $in;
-        } elseif (is_array($in) and isset($in['root'])) {
-            if ($force or ! isset($in['files'])) {
-                // If we are forcing a recompile or if for some reason the
-                // structure does not contain any file information we should
-                // specify the root to trigger a rebuild.
-                $root = $in['root'];
-            } elseif (isset($in['files']) and is_array($in['files'])) {
-                foreach ($in['files'] as $fname => $ftime) {
-                    if (! file_exists($fname) or filemtime($fname) > $ftime) {
-                        // One of the files we knew about previously has changed
-                        // so we should look at our incoming root again.
-                        $root = $in['root'];
-                        break;
-                    }
-                }
-            }
-        } else {
-            // TODO: Throw an exception? We got neither a string nor something
-            // that looks like a compatible lessphp cache structure.
-            return null;
-        }
-
-        if ($root !== null) {
-            // If we have a root value which means we should rebuild.
-            $out = array();
-            $out['root'] = $root;
-            $out['compiled'] = $this->compileFile($root);
-            $out['files'] = $this->scss->getParsedFiles();
-            $out['updated'] = time();
-            return $out;
-        } else {
-            // No changes, pass back the structure
-            // we were given initially.
-            return $in;
-        }
-    }
-
-    /**
-     * Constructor
-     *
-     * @param string                       $dir      Root directory to .scss files
-     * @param string                       $cacheDir Cache directory
-     * @param \Leafo\ScssPhp\Compiler|null $scss     SCSS compiler instance
-     */
-    public function __construct($dir, $cacheDir = null, $scss = null)
-    {
-        $this->dir = $dir;
-
-        if (! isset($cacheDir)) {
-            $cacheDir = $this->join($dir, 'scss_cache');
-        }
-
-        $this->cacheDir = $cacheDir;
-
-        if (! is_dir($this->cacheDir)) {
-            throw new ServerException('Cache directory doesn\'t exist: ' . $cacheDir);
-        }
-
-        if (! isset($scss)) {
-            $scss = new Compiler();
-            $scss->setImportPaths($this->dir);
-        }
-
-        $this->scss = $scss;
-        $this->showErrorsAsCSS = false;
-
-        if (! ini_get('date.timezone')) {
-            throw new ServerException('Default date.timezone not set');
-        }
-    }
-}
diff --git a/inc/scssphp--old/scss.inc.php b/inc/scssphp--old/scss.inc.php
deleted file mode 100644
index 13c84bf..0000000
--- a/inc/scssphp--old/scss.inc.php
+++ /dev/null
@@ -1,32 +0,0 @@
-<?php
-if (version_compare(PHP_VERSION, '5.4') < 0) {
-    throw new \Exception('scssphp requires PHP 5.4 or above');
-}
-
-if (! class_exists('Leafo\ScssPhp\Version', false)) {
-    include_once __DIR__ . '/src/Base/Range.php';
-    include_once __DIR__ . '/src/Block.php';
-    include_once __DIR__ . '/src/Colors.php';
-    include_once __DIR__ . '/src/Compiler.php';
-    include_once __DIR__ . '/src/Compiler/Environment.php';
-    include_once __DIR__ . '/src/Exception/CompilerException.php';
-    include_once __DIR__ . '/src/Exception/ParserException.php';
-    include_once __DIR__ . '/src/Exception/RangeException.php';
-    include_once __DIR__ . '/src/Exception/ServerException.php';
-    include_once __DIR__ . '/src/Formatter.php';
-    include_once __DIR__ . '/src/Formatter/Compact.php';
-    include_once __DIR__ . '/src/Formatter/Compressed.php';
-    include_once __DIR__ . '/src/Formatter/Crunched.php';
-    include_once __DIR__ . '/src/Formatter/Debug.php';
-    include_once __DIR__ . '/src/Formatter/Expanded.php';
-    include_once __DIR__ . '/src/Formatter/Nested.php';
-    include_once __DIR__ . '/src/Formatter/OutputBlock.php';
-    include_once __DIR__ . '/src/Node.php';
-    include_once __DIR__ . '/src/Node/Number.php';
-    include_once __DIR__ . '/src/Parser.php';
-    include_once __DIR__ . '/src/SourceMap/Base64VLQEncoder.php';
-    include_once __DIR__ . '/src/SourceMap/SourceMapGenerator.php';
-    include_once __DIR__ . '/src/Type.php';
-    include_once __DIR__ . '/src/Util.php';
-    include_once __DIR__ . '/src/Version.php';
-}
diff --git a/inc/scssphp--old/src/Base/Range.php b/inc/scssphp--old/src/Base/Range.php
deleted file mode 100644
index 8bcc6ec..0000000
--- a/inc/scssphp--old/src/Base/Range.php
+++ /dev/null
@@ -1,47 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2015-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp\Base;
-
-/**
- * Range
- *
- * @author Anthon Pang <anthon.pang@gmail.com>
- */
-class Range
-{
-    public $first;
-    public $last;
-
-    /**
-     * Initialize range
-     *
-     * @param integer|float $first
-     * @param integer|float $last
-     */
-    public function __construct($first, $last)
-    {
-        $this->first = $first;
-        $this->last = $last;
-    }
-
-    /**
-     * Test for inclusion in range
-     *
-     * @param integer|float $value
-     *
-     * @return boolean
-     */
-    public function includes($value)
-    {
-        return $value >= $this->first && $value <= $this->last;
-    }
-}
diff --git a/inc/scssphp--old/src/Block.php b/inc/scssphp--old/src/Block.php
deleted file mode 100644
index a6ef8e0..0000000
--- a/inc/scssphp--old/src/Block.php
+++ /dev/null
@@ -1,65 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp;
-
-/**
- * Block
- *
- * @author Anthon Pang <anthon.pang@gmail.com>
- */
-class Block
-{
-    /**
-     * @var string
-     */
-    public $type;
-
-    /**
-     * @var \Leafo\ScssPhp\Block
-     */
-    public $parent;
-
-    /**
-     * @var string
-     */
-    public $sourceName;
-
-    /**
-     * @var integer
-     */
-    public $sourceIndex;
-
-    /**
-     * @var integer
-     */
-    public $sourceLine;
-
-    /**
-     * @var integer
-     */
-    public $sourceColumn;
-
-    /**
-     * @var array
-     */
-    public $selectors;
-
-    /**
-     * @var array
-     */
-    public $comments;
-
-    /**
-     * @var array
-     */
-    public $children;
-}
diff --git a/inc/scssphp--old/src/Colors.php b/inc/scssphp--old/src/Colors.php
deleted file mode 100644
index 2314ea5..0000000
--- a/inc/scssphp--old/src/Colors.php
+++ /dev/null
@@ -1,179 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp;
-
-/**
- * CSS Colors
- *
- * @author Leaf Corcoran <leafot@gmail.com>
- */
-class Colors
-{
-    /**
-     * CSS Colors
-     *
-     * @see http://www.w3.org/TR/css3-color
-     *
-     * @var array
-     */
-    public static $cssColors = [
-        'aliceblue' => '240,248,255',
-        'antiquewhite' => '250,235,215',
-        'aqua' => '0,255,255',
-        'aquamarine' => '127,255,212',
-        'azure' => '240,255,255',
-        'beige' => '245,245,220',
-        'bisque' => '255,228,196',
-        'black' => '0,0,0',
-        'blanchedalmond' => '255,235,205',
-        'blue' => '0,0,255',
-        'blueviolet' => '138,43,226',
-        'brown' => '165,42,42',
-        'burlywood' => '222,184,135',
-        'cadetblue' => '95,158,160',
-        'chartreuse' => '127,255,0',
-        'chocolate' => '210,105,30',
-        'coral' => '255,127,80',
-        'cornflowerblue' => '100,149,237',
-        'cornsilk' => '255,248,220',
-        'crimson' => '220,20,60',
-        'cyan' => '0,255,255',
-        'darkblue' => '0,0,139',
-        'darkcyan' => '0,139,139',
-        'darkgoldenrod' => '184,134,11',
-        'darkgray' => '169,169,169',
-        'darkgreen' => '0,100,0',
-        'darkgrey' => '169,169,169',
-        'darkkhaki' => '189,183,107',
-        'darkmagenta' => '139,0,139',
-        'darkolivegreen' => '85,107,47',
-        'darkorange' => '255,140,0',
-        'darkorchid' => '153,50,204',
-        'darkred' => '139,0,0',
-        'darksalmon' => '233,150,122',
-        'darkseagreen' => '143,188,143',
-        'darkslateblue' => '72,61,139',
-        'darkslategray' => '47,79,79',
-        'darkslategrey' => '47,79,79',
-        'darkturquoise' => '0,206,209',
-        'darkviolet' => '148,0,211',
-        'deeppink' => '255,20,147',
-        'deepskyblue' => '0,191,255',
-        'dimgray' => '105,105,105',
-        'dimgrey' => '105,105,105',
-        'dodgerblue' => '30,144,255',
-        'firebrick' => '178,34,34',
-        'floralwhite' => '255,250,240',
-        'forestgreen' => '34,139,34',
-        'fuchsia' => '255,0,255',
-        'gainsboro' => '220,220,220',
-        'ghostwhite' => '248,248,255',
-        'gold' => '255,215,0',
-        'goldenrod' => '218,165,32',
-        'gray' => '128,128,128',
-        'green' => '0,128,0',
-        'greenyellow' => '173,255,47',
-        'grey' => '128,128,128',
-        'honeydew' => '240,255,240',
-        'hotpink' => '255,105,180',
-        'indianred' => '205,92,92',
-        'indigo' => '75,0,130',
-        'ivory' => '255,255,240',
-        'khaki' => '240,230,140',
-        'lavender' => '230,230,250',
-        'lavenderblush' => '255,240,245',
-        'lawngreen' => '124,252,0',
-        'lemonchiffon' => '255,250,205',
-        'lightblue' => '173,216,230',
-        'lightcoral' => '240,128,128',
-        'lightcyan' => '224,255,255',
-        'lightgoldenrodyellow' => '250,250,210',
-        'lightgray' => '211,211,211',
-        'lightgreen' => '144,238,144',
-        'lightgrey' => '211,211,211',
-        'lightpink' => '255,182,193',
-        'lightsalmon' => '255,160,122',
-        'lightseagreen' => '32,178,170',
-        'lightskyblue' => '135,206,250',
-        'lightslategray' => '119,136,153',
-        'lightslategrey' => '119,136,153',
-        'lightsteelblue' => '176,196,222',
-        'lightyellow' => '255,255,224',
-        'lime' => '0,255,0',
-        'limegreen' => '50,205,50',
-        'linen' => '250,240,230',
-        'magenta' => '255,0,255',
-        'maroon' => '128,0,0',
-        'mediumaquamarine' => '102,205,170',
-        'mediumblue' => '0,0,205',
-        'mediumorchid' => '186,85,211',
-        'mediumpurple' => '147,112,219',
-        'mediumseagreen' => '60,179,113',
-        'mediumslateblue' => '123,104,238',
-        'mediumspringgreen' => '0,250,154',
-        'mediumturquoise' => '72,209,204',
-        'mediumvioletred' => '199,21,133',
-        'midnightblue' => '25,25,112',
-        'mintcream' => '245,255,250',
-        'mistyrose' => '255,228,225',
-        'moccasin' => '255,228,181',
-        'navajowhite' => '255,222,173',
-        'navy' => '0,0,128',
-        'oldlace' => '253,245,230',
-        'olive' => '128,128,0',
-        'olivedrab' => '107,142,35',
-        'orange' => '255,165,0',
-        'orangered' => '255,69,0',
-        'orchid' => '218,112,214',
-        'palegoldenrod' => '238,232,170',
-        'palegreen' => '152,251,152',
-        'paleturquoise' => '175,238,238',
-        'palevioletred' => '219,112,147',
-        'papayawhip' => '255,239,213',
-        'peachpuff' => '255,218,185',
-        'peru' => '205,133,63',
-        'pink' => '255,192,203',
-        'plum' => '221,160,221',
-        'powderblue' => '176,224,230',
-        'purple' => '128,0,128',
-        'rebeccapurple' => '102,51,153',
-        'red' => '255,0,0',
-        'rosybrown' => '188,143,143',
-        'royalblue' => '65,105,225',
-        'saddlebrown' => '139,69,19',
-        'salmon' => '250,128,114',
-        'sandybrown' => '244,164,96',
-        'seagreen' => '46,139,87',
-        'seashell' => '255,245,238',
-        'sienna' => '160,82,45',
-        'silver' => '192,192,192',
-        'skyblue' => '135,206,235',
-        'slateblue' => '106,90,205',
-        'slategray' => '112,128,144',
-        'slategrey' => '112,128,144',
-        'snow' => '255,250,250',
-        'springgreen' => '0,255,127',
-        'steelblue' => '70,130,180',
-        'tan' => '210,180,140',
-        'teal' => '0,128,128',
-        'thistle' => '216,191,216',
-        'tomato' => '255,99,71',
-        'transparent' => '0,0,0,0',
-        'turquoise' => '64,224,208',
-        'violet' => '238,130,238',
-        'wheat' => '245,222,179',
-        'white' => '255,255,255',
-        'whitesmoke' => '245,245,245',
-        'yellow' => '255,255,0',
-        'yellowgreen' => '154,205,50',
-    ];
-}
diff --git a/inc/scssphp--old/src/Compiler.php b/inc/scssphp--old/src/Compiler.php
deleted file mode 100644
index 292e960..0000000
--- a/inc/scssphp--old/src/Compiler.php
+++ /dev/null
@@ -1,5336 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp;
-
-use Leafo\ScssPhp\Base\Range;
-use Leafo\ScssPhp\Block;
-use Leafo\ScssPhp\Colors;
-use Leafo\ScssPhp\Compiler\Environment;
-use Leafo\ScssPhp\Exception\CompilerException;
-use Leafo\ScssPhp\Formatter\OutputBlock;
-use Leafo\ScssPhp\Node;
-use Leafo\ScssPhp\SourceMap\SourceMapGenerator;
-use Leafo\ScssPhp\Type;
-use Leafo\ScssPhp\Parser;
-use Leafo\ScssPhp\Util;
-
-/**
- * The scss compiler and parser.
- *
- * Converting SCSS to CSS is a three stage process. The incoming file is parsed
- * by `Parser` into a syntax tree, then it is compiled into another tree
- * representing the CSS structure by `Compiler`. The CSS tree is fed into a
- * formatter, like `Formatter` which then outputs CSS as a string.
- *
- * During the first compile, all values are *reduced*, which means that their
- * types are brought to the lowest form before being dump as strings. This
- * handles math equations, variable dereferences, and the like.
- *
- * The `compile` function of `Compiler` is the entry point.
- *
- * In summary:
- *
- * The `Compiler` class creates an instance of the parser, feeds it SCSS code,
- * then transforms the resulting tree to a CSS tree. This class also holds the
- * evaluation context, such as all available mixins and variables at any given
- * time.
- *
- * The `Parser` class is only concerned with parsing its input.
- *
- * The `Formatter` takes a CSS tree, and dumps it to a formatted string,
- * handling things like indentation.
- */
-
-/**
- * SCSS compiler
- *
- * @author Leaf Corcoran <leafot@gmail.com>
- */
-class Compiler
-{
-    const LINE_COMMENTS = 1;
-    const DEBUG_INFO    = 2;
-
-    const WITH_RULE     = 1;
-    const WITH_MEDIA    = 2;
-    const WITH_SUPPORTS = 4;
-    const WITH_ALL      = 7;
-
-    const SOURCE_MAP_NONE   = 0;
-    const SOURCE_MAP_INLINE = 1;
-    const SOURCE_MAP_FILE   = 2;
-
-    /**
-     * @var array
-     */
-    static protected $operatorNames = [
-        '+'   => 'add',
-        '-'   => 'sub',
-        '*'   => 'mul',
-        '/'   => 'div',
-        '%'   => 'mod',
-
-        '=='  => 'eq',
-        '!='  => 'neq',
-        '<'   => 'lt',
-        '>'   => 'gt',
-
-        '<='  => 'lte',
-        '>='  => 'gte',
-        '<=>' => 'cmp',
-    ];
-
-    /**
-     * @var array
-     */
-    static protected $namespaces = [
-        'special'  => '%',
-        'mixin'    => '@',
-        'function' => '^',
-    ];
-
-    static public $true = [Type::T_KEYWORD, 'true'];
-    static public $false = [Type::T_KEYWORD, 'false'];
-    static public $null = [Type::T_NULL];
-    static public $nullString = [Type::T_STRING, '', []];
-    static public $defaultValue = [Type::T_KEYWORD, ''];
-    static public $selfSelector = [Type::T_SELF];
-    static public $emptyList = [Type::T_LIST, '', []];
-    static public $emptyMap = [Type::T_MAP, [], []];
-    static public $emptyString = [Type::T_STRING, '"', []];
-    static public $with = [Type::T_KEYWORD, 'with'];
-    static public $without = [Type::T_KEYWORD, 'without'];
-
-    protected $importPaths = [''];
-    protected $importCache = [];
-    protected $importedFiles = [];
-    protected $userFunctions = [];
-    protected $registeredVars = [];
-    protected $registeredFeatures = [
-        'extend-selector-pseudoclass' => false,
-        'at-error'                    => true,
-        'units-level-3'               => false,
-        'global-variable-shadowing'   => false,
-    ];
-
-    protected $encoding = null;
-    protected $lineNumberStyle = null;
-
-    protected $sourceMap = self::SOURCE_MAP_NONE;
-    protected $sourceMapOptions = [];
-
-    /**
-     * @var string|\Leafo\ScssPhp\Formatter
-     */
-    protected $formatter = 'Leafo\ScssPhp\Formatter\Nested';
-
-    protected $rootEnv;
-    protected $rootBlock;
-
-    /**
-     * @var \Leafo\ScssPhp\Compiler\Environment
-     */
-    protected $env;
-    protected $scope;
-    protected $storeEnv;
-    protected $charsetSeen;
-    protected $sourceNames;
-
-    private $indentLevel;
-    private $commentsSeen;
-    private $extends;
-    private $extendsMap;
-    private $parsedFiles;
-    private $parser;
-    private $sourceIndex;
-    private $sourceLine;
-    private $sourceColumn;
-    private $stderr;
-    private $shouldEvaluate;
-    private $ignoreErrors;
-
-    /**
-     * Constructor
-     */
-    public function __construct()
-    {
-        $this->parsedFiles = [];
-        $this->sourceNames = [];
-    }
-
-    /**
-     * Compile scss
-     *
-     * @api
-     *
-     * @param string $code
-     * @param string $path
-     *
-     * @return string
-     */
-    public function compile($code, $path = null)
-    {
-        $this->indentLevel    = -1;
-        $this->commentsSeen   = [];
-        $this->extends        = [];
-        $this->extendsMap     = [];
-        $this->sourceIndex    = null;
-        $this->sourceLine     = null;
-        $this->sourceColumn   = null;
-        $this->env            = null;
-        $this->scope          = null;
-        $this->storeEnv       = null;
-        $this->charsetSeen    = null;
-        $this->shouldEvaluate = null;
-        $this->stderr         = fopen('php://stderr', 'w');
-
-        $this->parser = $this->parserFactory($path);
-        $tree = $this->parser->parse($code);
-        $this->parser = null;
-
-        $this->formatter = new $this->formatter();
-        $this->rootBlock = null;
-        $this->rootEnv   = $this->pushEnv($tree);
-
-        $this->injectVariables($this->registeredVars);
-        $this->compileRoot($tree);
-        $this->popEnv();
-
-        $sourceMapGenerator = null;
-
-        if ($this->sourceMap) {
-            if (is_object($this->sourceMap) && $this->sourceMap instanceof SourceMapGenerator) {
-                $sourceMapGenerator = $this->sourceMap;
-                $this->sourceMap = self::SOURCE_MAP_FILE;
-            } elseif ($this->sourceMap !== self::SOURCE_MAP_NONE) {
-                $sourceMapGenerator = new SourceMapGenerator($this->sourceMapOptions);
-            }
-        }
-
-        $out = $this->formatter->format($this->scope, $sourceMapGenerator);
-
-        if (! empty($out) && $this->sourceMap && $this->sourceMap !== self::SOURCE_MAP_NONE) {
-            $sourceMap    = $sourceMapGenerator->generateJson();
-            $sourceMapUrl = null;
-
-            switch ($this->sourceMap) {
-                case self::SOURCE_MAP_INLINE:
-                    $sourceMapUrl = sprintf('data:application/json,%s', Util::encodeURIComponent($sourceMap));
-                    break;
-
-                case self::SOURCE_MAP_FILE:
-                    $sourceMapUrl = $sourceMapGenerator->saveMap($sourceMap);
-                    break;
-            }
-
-            $out .= sprintf('/*# sourceMappingURL=%s */', $sourceMapUrl);
-        }
-
-        return $out;
-    }
-
-    /**
-     * Instantiate parser
-     *
-     * @param string $path
-     *
-     * @return \Leafo\ScssPhp\Parser
-     */
-    protected function parserFactory($path)
-    {
-        $parser = new Parser($path, count($this->sourceNames), $this->encoding);
-
-        $this->sourceNames[] = $path;
-        $this->addParsedFile($path);
-
-        return $parser;
-    }
-
-    /**
-     * Is self extend?
-     *
-     * @param array $target
-     * @param array $origin
-     *
-     * @return boolean
-     */
-    protected function isSelfExtend($target, $origin)
-    {
-        foreach ($origin as $sel) {
-            if (in_array($target, $sel)) {
-                return true;
-            }
-        }
-
-        return false;
-    }
-
-    /**
-     * Push extends
-     *
-     * @param array     $target
-     * @param array     $origin
-     * @param \stdClass $block
-     */
-    protected function pushExtends($target, $origin, $block)
-    {
-        if ($this->isSelfExtend($target, $origin)) {
-            return;
-        }
-
-        $i = count($this->extends);
-        $this->extends[] = [$target, $origin, $block];
-
-        foreach ($target as $part) {
-            if (isset($this->extendsMap[$part])) {
-                $this->extendsMap[$part][] = $i;
-            } else {
-                $this->extendsMap[$part] = [$i];
-            }
-        }
-    }
-
-    /**
-     * Make output block
-     *
-     * @param string $type
-     * @param array  $selectors
-     *
-     * @return \Leafo\ScssPhp\Formatter\OutputBlock
-     */
-    protected function makeOutputBlock($type, $selectors = null)
-    {
-        $out = new OutputBlock;
-        $out->type         = $type;
-        $out->lines        = [];
-        $out->children     = [];
-        $out->parent       = $this->scope;
-        $out->selectors    = $selectors;
-        $out->depth        = $this->env->depth;
-        $out->sourceName   = $this->env->block->sourceName;
-        $out->sourceLine   = $this->env->block->sourceLine;
-        $out->sourceColumn = $this->env->block->sourceColumn;
-
-        return $out;
-    }
-
-    /**
-     * Compile root
-     *
-     * @param \Leafo\ScssPhp\Block $rootBlock
-     */
-    protected function compileRoot(Block $rootBlock)
-    {
-        $this->rootBlock = $this->scope = $this->makeOutputBlock(Type::T_ROOT);
-
-        $this->compileChildrenNoReturn($rootBlock->children, $this->scope);
-        $this->flattenSelectors($this->scope);
-        $this->missingSelectors();
-    }
-
-    /**
-     * Report missing selectors
-     */
-    protected function missingSelectors()
-    {
-        foreach ($this->extends as $extend) {
-            if (isset($extend[3])) {
-                continue;
-            }
-
-            list($target, $origin, $block) = $extend;
-
-            // ignore if !optional
-            if ($block[2]) {
-                continue;
-            }
-
-            $target = implode(' ', $target);
-            $origin = $this->collapseSelectors($origin);
-
-            $this->sourceLine = $block[Parser::SOURCE_LINE];
-            $this->throwError("\"$origin\" failed to @extend \"$target\". The selector \"$target\" was not found.");
-        }
-    }
-
-    /**
-     * Flatten selectors
-     *
-     * @param \Leafo\ScssPhp\Formatter\OutputBlock $block
-     * @param string                               $parentKey
-     */
-    protected function flattenSelectors(OutputBlock $block, $parentKey = null)
-    {
-        if ($block->selectors) {
-            $selectors = [];
-
-            foreach ($block->selectors as $s) {
-                $selectors[] = $s;
-
-                if (! is_array($s)) {
-                    continue;
-                }
-
-                // check extends
-                if (! empty($this->extendsMap)) {
-                    $this->matchExtends($s, $selectors);
-
-                    // remove duplicates
-                    array_walk($selectors, function (&$value) {
-                        $value = serialize($value);
-                    });
-
-                    $selectors = array_unique($selectors);
-
-                    array_walk($selectors, function (&$value) {
-                        $value = unserialize($value);
-                    });
-                }
-            }
-
-            $block->selectors = [];
-            $placeholderSelector = false;
-
-            foreach ($selectors as $selector) {
-                if ($this->hasSelectorPlaceholder($selector)) {
-                    $placeholderSelector = true;
-                    continue;
-                }
-
-                $block->selectors[] = $this->compileSelector($selector);
-            }
-
-            if ($placeholderSelector && 0 === count($block->selectors) && null !== $parentKey) {
-                unset($block->parent->children[$parentKey]);
-
-                return;
-            }
-        }
-
-        foreach ($block->children as $key => $child) {
-            $this->flattenSelectors($child, $key);
-        }
-    }
-
-    /**
-     * Match extends
-     *
-     * @param array   $selector
-     * @param array   $out
-     * @param integer $from
-     * @param boolean $initial
-     */
-    protected function matchExtends($selector, &$out, $from = 0, $initial = true)
-    {
-        foreach ($selector as $i => $part) {
-            if ($i < $from) {
-                continue;
-            }
-
-            if ($this->matchExtendsSingle($part, $origin)) {
-                $after = array_slice($selector, $i + 1);
-                $before = array_slice($selector, 0, $i);
-
-                list($before, $nonBreakableBefore) = $this->extractRelationshipFromFragment($before);
-
-                foreach ($origin as $new) {
-                    $k = 0;
-
-                    // remove shared parts
-                    if ($initial) {
-                        while ($k < $i && isset($new[$k]) && $selector[$k] === $new[$k]) {
-                            $k++;
-                        }
-                    }
-
-                    $replacement = [];
-                    $tempReplacement = $k > 0 ? array_slice($new, $k) : $new;
-
-                    for ($l = count($tempReplacement) - 1; $l >= 0; $l--) {
-                        $slice = $tempReplacement[$l];
-                        array_unshift($replacement, $slice);
-
-                        if (! $this->isImmediateRelationshipCombinator(end($slice))) {
-                            break;
-                        }
-                    }
-
-                    $afterBefore = $l != 0 ? array_slice($tempReplacement, 0, $l) : [];
-
-                    // Merge shared direct relationships.
-                    $mergedBefore = $this->mergeDirectRelationships($afterBefore, $nonBreakableBefore);
-
-                    $result = array_merge(
-                        $before,
-                        $mergedBefore,
-                        $replacement,
-                        $after
-                    );
-
-                    if ($result === $selector) {
-                        continue;
-                    }
-
-                    $out[] = $result;
-
-                    // recursively check for more matches
-                    $this->matchExtends($result, $out, count($before) + count($mergedBefore), false);
-
-                    // selector sequence merging
-                    if (! empty($before) && count($new) > 1) {
-                        $sharedParts = $k > 0 ? array_slice($before, 0, $k) : [];
-                        $postSharedParts = $k > 0 ? array_slice($before, $k) : $before;
-
-                        list($injectBetweenSharedParts, $nonBreakable2) = $this->extractRelationshipFromFragment($afterBefore);
-
-                        $result2 = array_merge(
-                            $sharedParts,
-                            $injectBetweenSharedParts,
-                            $postSharedParts,
-                            $nonBreakable2,
-                            $nonBreakableBefore,
-                            $replacement,
-                            $after
-                        );
-
-                        $out[] = $result2;
-                    }
-                }
-            }
-        }
-    }
-
-    /**
-     * Match extends single
-     *
-     * @param array $rawSingle
-     * @param array $outOrigin
-     *
-     * @return boolean
-     */
-    protected function matchExtendsSingle($rawSingle, &$outOrigin)
-    {
-        $counts = [];
-        $single = [];
-
-        foreach ($rawSingle as $part) {
-            // matches Number
-            if (! is_string($part)) {
-                return false;
-            }
-
-            if (! preg_match('/^[\[.:#%]/', $part) && count($single)) {
-                $single[count($single) - 1] .= $part;
-            } else {
-                $single[] = $part;
-            }
-        }
-
-        $extendingDecoratedTag = false;
-
-        if (count($single) > 1) {
-            $matches = null;
-            $extendingDecoratedTag = preg_match('/^[a-z0-9]+$/i', $single[0], $matches) ? $matches[0] : false;
-        }
-
-        foreach ($single as $part) {
-            if (isset($this->extendsMap[$part])) {
-                foreach ($this->extendsMap[$part] as $idx) {
-                    $counts[$idx] = isset($counts[$idx]) ? $counts[$idx] + 1 : 1;
-                }
-            }
-        }
-
-        $outOrigin = [];
-        $found = false;
-
-        foreach ($counts as $idx => $count) {
-            list($target, $origin, /* $block */) = $this->extends[$idx];
-
-            // check count
-            if ($count !== count($target)) {
-                continue;
-            }
-
-            $this->extends[$idx][3] = true;
-
-            $rem = array_diff($single, $target);
-
-            foreach ($origin as $j => $new) {
-                // prevent infinite loop when target extends itself
-                if ($this->isSelfExtend($single, $origin)) {
-                    return false;
-                }
-
-                $replacement = end($new);
-
-                // Extending a decorated tag with another tag is not possible.
-                if ($extendingDecoratedTag && $replacement[0] != $extendingDecoratedTag &&
-                    preg_match('/^[a-z0-9]+$/i', $replacement[0])
-                ) {
-                    unset($origin[$j]);
-                    continue;
-                }
-
-                $combined = $this->combineSelectorSingle($replacement, $rem);
-
-                if (count(array_diff($combined, $origin[$j][count($origin[$j]) - 1]))) {
-                    $origin[$j][count($origin[$j]) - 1] = $combined;
-                }
-            }
-
-            $outOrigin = array_merge($outOrigin, $origin);
-
-            $found = true;
-        }
-
-        return $found;
-    }
-
-
-    /**
-     * Extract a relationship from the fragment.
-     *
-     * When extracting the last portion of a selector we will be left with a
-     * fragment which may end with a direction relationship combinator. This
-     * method will extract the relationship fragment and return it along side
-     * the rest.
-     *
-     * @param array $fragment The selector fragment maybe ending with a direction relationship combinator.
-     * @return array The selector without the relationship fragment if any, the relationship fragment.
-     */
-    protected function extractRelationshipFromFragment(array $fragment)
-    {
-        $parents = [];
-        $children = [];
-        $j = $i = count($fragment);
-
-        for (;;) {
-            $children = $j != $i ? array_slice($fragment, $j, $i - $j) : [];
-            $parents = array_slice($fragment, 0, $j);
-            $slice = end($parents);
-
-            if (empty($slice) || ! $this->isImmediateRelationshipCombinator($slice[0])) {
-                break;
-            }
-
-            $j -= 2;
-        }
-
-        return [$parents, $children];
-    }
-
-    /**
-     * Combine selector single
-     *
-     * @param array $base
-     * @param array $other
-     *
-     * @return array
-     */
-    protected function combineSelectorSingle($base, $other)
-    {
-        $tag = [];
-        $out = [];
-        $wasTag = true;
-
-        foreach ([$base, $other] as $single) {
-            foreach ($single as $part) {
-                if (preg_match('/^[\[.:#]/', $part)) {
-                    $out[] = $part;
-                    $wasTag = false;
-                } elseif (preg_match('/^[^_-]/', $part)) {
-                    $tag[] = $part;
-                    $wasTag = true;
-                } elseif ($wasTag) {
-                    $tag[count($tag) - 1] .= $part;
-                } else {
-                    $out[count($out) - 1] .= $part;
-                }
-            }
-        }
-
-        if (count($tag)) {
-            array_unshift($out, $tag[0]);
-        }
-
-        return $out;
-    }
-
-    /**
-     * Compile media
-     *
-     * @param \Leafo\ScssPhp\Block $media
-     */
-    protected function compileMedia(Block $media)
-    {
-        $this->pushEnv($media);
-
-        $mediaQuery = $this->compileMediaQuery($this->multiplyMedia($this->env));
-
-        if (! empty($mediaQuery)) {
-            $this->scope = $this->makeOutputBlock(Type::T_MEDIA, [$mediaQuery]);
-
-            $parentScope = $this->mediaParent($this->scope);
-            $parentScope->children[] = $this->scope;
-
-            // top level properties in a media cause it to be wrapped
-            $needsWrap = false;
-
-            foreach ($media->children as $child) {
-                $type = $child[0];
-
-                if ($type !== Type::T_BLOCK &&
-                    $type !== Type::T_MEDIA &&
-                    $type !== Type::T_DIRECTIVE &&
-                    $type !== Type::T_IMPORT
-                ) {
-                    $needsWrap = true;
-                    break;
-                }
-            }
-
-            if ($needsWrap) {
-                $wrapped = new Block;
-                $wrapped->sourceName   = $media->sourceName;
-                $wrapped->sourceIndex  = $media->sourceIndex;
-                $wrapped->sourceLine   = $media->sourceLine;
-                $wrapped->sourceColumn = $media->sourceColumn;
-                $wrapped->selectors    = [];
-                $wrapped->comments     = [];
-                $wrapped->parent       = $media;
-                $wrapped->children     = $media->children;
-
-                $media->children = [[Type::T_BLOCK, $wrapped]];
-            }
-
-            $this->compileChildrenNoReturn($media->children, $this->scope);
-
-            $this->scope = $this->scope->parent;
-        }
-
-        $this->popEnv();
-    }
-
-    /**
-     * Media parent
-     *
-     * @param \Leafo\ScssPhp\Formatter\OutputBlock $scope
-     *
-     * @return \Leafo\ScssPhp\Formatter\OutputBlock
-     */
-    protected function mediaParent(OutputBlock $scope)
-    {
-        while (! empty($scope->parent)) {
-            if (! empty($scope->type) && $scope->type !== Type::T_MEDIA) {
-                break;
-            }
-
-            $scope = $scope->parent;
-        }
-
-        return $scope;
-    }
-
-    /**
-     * Compile directive
-     *
-     * @param \Leafo\ScssPhp\Block $block
-     */
-    protected function compileDirective(Block $block)
-    {
-        $s = '@' . $block->name;
-
-        if (! empty($block->value)) {
-            $s .= ' ' . $this->compileValue($block->value);
-        }
-
-        if ($block->name === 'keyframes' || substr($block->name, -10) === '-keyframes') {
-            $this->compileKeyframeBlock($block, [$s]);
-        } else {
-            $this->compileNestedBlock($block, [$s]);
-        }
-    }
-
-    /**
-     * Compile at-root
-     *
-     * @param \Leafo\ScssPhp\Block $block
-     */
-    protected function compileAtRoot(Block $block)
-    {
-        $env     = $this->pushEnv($block);
-        $envs    = $this->compactEnv($env);
-        $without = isset($block->with) ? $this->compileWith($block->with) : static::WITH_RULE;
-
-        // wrap inline selector
-        if ($block->selector) {
-            $wrapped = new Block;
-            $wrapped->sourceName   = $block->sourceName;
-            $wrapped->sourceIndex  = $block->sourceIndex;
-            $wrapped->sourceLine   = $block->sourceLine;
-            $wrapped->sourceColumn = $block->sourceColumn;
-            $wrapped->selectors    = $block->selector;
-            $wrapped->comments     = [];
-            $wrapped->parent       = $block;
-            $wrapped->children     = $block->children;
-
-            $block->children = [[Type::T_BLOCK, $wrapped]];
-        }
-
-        $this->env = $this->filterWithout($envs, $without);
-        $newBlock  = $this->spliceTree($envs, $block, $without);
-
-        $saveScope   = $this->scope;
-        $this->scope = $this->rootBlock;
-
-        $this->compileChild($newBlock, $this->scope);
-
-        $this->scope = $saveScope;
-        $this->env   = $this->extractEnv($envs);
-
-        $this->popEnv();
-    }
-
-    /**
-     * Splice parse tree
-     *
-     * @param array                $envs
-     * @param \Leafo\ScssPhp\Block $block
-     * @param integer              $without
-     *
-     * @return array
-     */
-    private function spliceTree($envs, Block $block, $without)
-    {
-        $newBlock = null;
-
-        foreach ($envs as $e) {
-            if (! isset($e->block)) {
-                continue;
-            }
-
-            if ($e->block === $block) {
-                continue;
-            }
-
-            if (isset($e->block->type) && $e->block->type === Type::T_AT_ROOT) {
-                continue;
-            }
-
-            if ($e->block && $this->isWithout($without, $e->block)) {
-                continue;
-            }
-
-            $b = new Block;
-            $b->sourceName   = $e->block->sourceName;
-            $b->sourceIndex  = $e->block->sourceIndex;
-            $b->sourceLine   = $e->block->sourceLine;
-            $b->sourceColumn = $e->block->sourceColumn;
-            $b->selectors    = [];
-            $b->comments     = $e->block->comments;
-            $b->parent       = null;
-
-            if ($newBlock) {
-                $type = isset($newBlock->type) ? $newBlock->type : Type::T_BLOCK;
-
-                $b->children = [[$type, $newBlock]];
-
-                $newBlock->parent = $b;
-            } elseif (count($block->children)) {
-                foreach ($block->children as $child) {
-                    if ($child[0] === Type::T_BLOCK) {
-                        $child[1]->parent = $b;
-                    }
-                }
-
-                $b->children = $block->children;
-            }
-
-            if (isset($e->block->type)) {
-                $b->type = $e->block->type;
-            }
-
-            if (isset($e->block->name)) {
-                $b->name = $e->block->name;
-            }
-
-            if (isset($e->block->queryList)) {
-                $b->queryList = $e->block->queryList;
-            }
-
-            if (isset($e->block->value)) {
-                $b->value = $e->block->value;
-            }
-
-            $newBlock = $b;
-        }
-
-        $type = isset($newBlock->type) ? $newBlock->type : Type::T_BLOCK;
-
-        return [$type, $newBlock];
-    }
-
-    /**
-     * Compile @at-root's with: inclusion / without: exclusion into filter flags
-     *
-     * @param array $with
-     *
-     * @return integer
-     */
-    private function compileWith($with)
-    {
-        static $mapping = [
-            'rule'     => self::WITH_RULE,
-            'media'    => self::WITH_MEDIA,
-            'supports' => self::WITH_SUPPORTS,
-            'all'      => self::WITH_ALL,
-        ];
-
-        // exclude selectors by default
-        $without = static::WITH_RULE;
-
-        if ($this->libMapHasKey([$with, static::$with])) {
-            $without = static::WITH_ALL;
-
-            $list = $this->coerceList($this->libMapGet([$with, static::$with]));
-
-            foreach ($list[2] as $item) {
-                $keyword = $this->compileStringContent($this->coerceString($item));
-
-                if (array_key_exists($keyword, $mapping)) {
-                    $without &= ~($mapping[$keyword]);
-                }
-            }
-        }
-
-        if ($this->libMapHasKey([$with, static::$without])) {
-            $without = 0;
-
-            $list = $this->coerceList($this->libMapGet([$with, static::$without]));
-
-            foreach ($list[2] as $item) {
-                $keyword = $this->compileStringContent($this->coerceString($item));
-
-                if (array_key_exists($keyword, $mapping)) {
-                    $without |= $mapping[$keyword];
-                }
-            }
-        }
-
-        return $without;
-    }
-
-    /**
-     * Filter env stack
-     *
-     * @param array   $envs
-     * @param integer $without
-     *
-     * @return \Leafo\ScssPhp\Compiler\Environment
-     */
-    private function filterWithout($envs, $without)
-    {
-        $filtered = [];
-
-        foreach ($envs as $e) {
-            if ($e->block && $this->isWithout($without, $e->block)) {
-                continue;
-            }
-
-            $filtered[] = $e;
-        }
-
-        return $this->extractEnv($filtered);
-    }
-
-    /**
-     * Filter WITH rules
-     *
-     * @param integer              $without
-     * @param \Leafo\ScssPhp\Block $block
-     *
-     * @return boolean
-     */
-    private function isWithout($without, Block $block)
-    {
-        if ((($without & static::WITH_RULE) && isset($block->selectors)) ||
-            (($without & static::WITH_MEDIA) &&
-                isset($block->type) && $block->type === Type::T_MEDIA) ||
-            (($without & static::WITH_SUPPORTS) &&
-                isset($block->type) && $block->type === Type::T_DIRECTIVE &&
-                isset($block->name) && $block->name === 'supports')
-        ) {
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Compile keyframe block
-     *
-     * @param \Leafo\ScssPhp\Block $block
-     * @param array                $selectors
-     */
-    protected function compileKeyframeBlock(Block $block, $selectors)
-    {
-        $env = $this->pushEnv($block);
-
-        $envs = $this->compactEnv($env);
-
-        $this->env = $this->extractEnv(array_filter($envs, function (Environment $e) {
-            return ! isset($e->block->selectors);
-        }));
-
-        $this->scope = $this->makeOutputBlock($block->type, $selectors);
-        $this->scope->depth = 1;
-        $this->scope->parent->children[] = $this->scope;
-
-        $this->compileChildrenNoReturn($block->children, $this->scope);
-
-        $this->scope = $this->scope->parent;
-        $this->env   = $this->extractEnv($envs);
-
-        $this->popEnv();
-    }
-
-    /**
-     * Compile nested block
-     *
-     * @param \Leafo\ScssPhp\Block $block
-     * @param array                $selectors
-     */
-    protected function compileNestedBlock(Block $block, $selectors)
-    {
-        $this->pushEnv($block);
-
-        $this->scope = $this->makeOutputBlock($block->type, $selectors);
-        $this->scope->parent->children[] = $this->scope;
-
-        $this->compileChildrenNoReturn($block->children, $this->scope);
-
-        $this->scope = $this->scope->parent;
-
-        $this->popEnv();
-    }
-
-    /**
-     * Recursively compiles a block.
-     *
-     * A block is analogous to a CSS block in most cases. A single SCSS document
-     * is encapsulated in a block when parsed, but it does not have parent tags
-     * so all of its children appear on the root level when compiled.
-     *
-     * Blocks are made up of selectors and children.
-     *
-     * The children of a block are just all the blocks that are defined within.
-     *
-     * Compiling the block involves pushing a fresh environment on the stack,
-     * and iterating through the props, compiling each one.
-     *
-     * @see Compiler::compileChild()
-     *
-     * @param \Leafo\ScssPhp\Block $block
-     */
-    protected function compileBlock(Block $block)
-    {
-        $env = $this->pushEnv($block);
-        $env->selectors = $this->evalSelectors($block->selectors);
-
-        $out = $this->makeOutputBlock(null);
-
-        if (isset($this->lineNumberStyle) && count($env->selectors) && count($block->children)) {
-            $annotation = $this->makeOutputBlock(Type::T_COMMENT);
-            $annotation->depth = 0;
-
-            $file = $this->sourceNames[$block->sourceIndex];
-            $line = $block->sourceLine;
-
-            switch ($this->lineNumberStyle) {
-                case static::LINE_COMMENTS:
-                    $annotation->lines[] = '/* line ' . $line
-                                         . ($file ? ', ' . $file : '')
-                                         . ' */';
-                    break;
-
-                case static::DEBUG_INFO:
-                    $annotation->lines[] = '@media -sass-debug-info{'
-                                         . ($file ? 'filename{font-family:"' . $file . '"}' : '')
-                                         . 'line{font-family:' . $line . '}}';
-                    break;
-            }
-
-            $this->scope->children[] = $annotation;
-        }
-
-        $this->scope->children[] = $out;
-
-        if (count($block->children)) {
-            $out->selectors = $this->multiplySelectors($env);
-
-            $this->compileChildrenNoReturn($block->children, $out);
-        }
-
-        $this->formatter->stripSemicolon($out->lines);
-
-        $this->popEnv();
-    }
-
-    /**
-     * Compile root level comment
-     *
-     * @param array $block
-     */
-    protected function compileComment($block)
-    {
-        $out = $this->makeOutputBlock(Type::T_COMMENT);
-        $out->lines[] = $block[1];
-        $this->scope->children[] = $out;
-    }
-
-    /**
-     * Evaluate selectors
-     *
-     * @param array $selectors
-     *
-     * @return array
-     */
-    protected function evalSelectors($selectors)
-    {
-        $this->shouldEvaluate = false;
-
-        $selectors = array_map([$this, 'evalSelector'], $selectors);
-
-        // after evaluating interpolates, we might need a second pass
-        if ($this->shouldEvaluate) {
-            $buffer = $this->collapseSelectors($selectors);
-            $parser = $this->parserFactory(__METHOD__);
-
-            if ($parser->parseSelector($buffer, $newSelectors)) {
-                $selectors = array_map([$this, 'evalSelector'], $newSelectors);
-            }
-        }
-
-        return $selectors;
-    }
-
-    /**
-     * Evaluate selector
-     *
-     * @param array $selector
-     *
-     * @return array
-     */
-    protected function evalSelector($selector)
-    {
-        return array_map([$this, 'evalSelectorPart'], $selector);
-    }
-
-    /**
-     * Evaluate selector part; replaces all the interpolates, stripping quotes
-     *
-     * @param array $part
-     *
-     * @return array
-     */
-    protected function evalSelectorPart($part)
-    {
-        foreach ($part as &$p) {
-            if (is_array($p) && ($p[0] === Type::T_INTERPOLATE || $p[0] === Type::T_STRING)) {
-                $p = $this->compileValue($p);
-
-                // force re-evaluation
-                if (strpos($p, '&') !== false || strpos($p, ',') !== false) {
-                    $this->shouldEvaluate = true;
-                }
-            } elseif (is_string($p) && strlen($p) >= 2 &&
-                ($first = $p[0]) && ($first === '"' || $first === "'") &&
-                substr($p, -1) === $first
-            ) {
-                $p = substr($p, 1, -1);
-            }
-        }
-
-        return $this->flattenSelectorSingle($part);
-    }
-
-    /**
-     * Collapse selectors
-     *
-     * @param array $selectors
-     *
-     * @return string
-     */
-    protected function collapseSelectors($selectors)
-    {
-        $parts = [];
-
-        foreach ($selectors as $selector) {
-            $output = '';
-
-            array_walk_recursive(
-                $selector,
-                function ($value, $key) use (&$output) {
-                    $output .= $value;
-                }
-            );
-
-            $parts[] = $output;
-        }
-
-        return implode(', ', $parts);
-    }
-
-    /**
-     * Flatten selector single; joins together .classes and #ids
-     *
-     * @param array $single
-     *
-     * @return array
-     */
-    protected function flattenSelectorSingle($single)
-    {
-        $joined = [];
-
-        foreach ($single as $part) {
-            if (empty($joined) ||
-                ! is_string($part) ||
-                preg_match('/[\[.:#%]/', $part)
-            ) {
-                $joined[] = $part;
-                continue;
-            }
-
-            if (is_array(end($joined))) {
-                $joined[] = $part;
-            } else {
-                $joined[count($joined) - 1] .= $part;
-            }
-        }
-
-        return $joined;
-    }
-
-    /**
-     * Compile selector to string; self(&) should have been replaced by now
-     *
-     * @param string|array $selector
-     *
-     * @return string
-     */
-    protected function compileSelector($selector)
-    {
-        if (! is_array($selector)) {
-            return $selector; // media and the like
-        }
-
-        return implode(
-            ' ',
-            array_map(
-                [$this, 'compileSelectorPart'],
-                $selector
-            )
-        );
-    }
-
-    /**
-     * Compile selector part
-     *
-     * @param array $piece
-     *
-     * @return string
-     */
-    protected function compileSelectorPart($piece)
-    {
-        foreach ($piece as &$p) {
-            if (! is_array($p)) {
-                continue;
-            }
-
-            switch ($p[0]) {
-                case Type::T_SELF:
-                    $p = '&';
-                    break;
-
-                default:
-                    $p = $this->compileValue($p);
-                    break;
-            }
-        }
-
-        return implode($piece);
-    }
-
-    /**
-     * Has selector placeholder?
-     *
-     * @param array $selector
-     *
-     * @return boolean
-     */
-    protected function hasSelectorPlaceholder($selector)
-    {
-        if (! is_array($selector)) {
-            return false;
-        }
-
-        foreach ($selector as $parts) {
-            foreach ($parts as $part) {
-                if (strlen($part) && '%' === $part[0]) {
-                    return true;
-                }
-            }
-        }
-
-        return false;
-    }
-
-    /**
-     * Compile children and return result
-     *
-     * @param array                                $stms
-     * @param \Leafo\ScssPhp\Formatter\OutputBlock $out
-     *
-     * @return array
-     */
-    protected function compileChildren($stms, OutputBlock $out)
-    {
-        foreach ($stms as $stm) {
-            $ret = $this->compileChild($stm, $out);
-
-            if (isset($ret)) {
-                return $ret;
-            }
-        }
-    }
-
-    /**
-     * Compile children and throw exception if unexpected @return
-     *
-     * @param array                                $stms
-     * @param \Leafo\ScssPhp\Formatter\OutputBlock $out
-     *
-     * @throws \Exception
-     */
-    protected function compileChildrenNoReturn($stms, OutputBlock $out)
-    {
-        foreach ($stms as $stm) {
-            $ret = $this->compileChild($stm, $out);
-
-            if (isset($ret)) {
-                $this->throwError('@return may only be used within a function');
-
-                return;
-            }
-        }
-    }
-
-    /**
-     * Compile media query
-     *
-     * @param array $queryList
-     *
-     * @return string
-     */
-    protected function compileMediaQuery($queryList)
-    {
-        $out = '@media';
-        $first = true;
-
-        foreach ($queryList as $query) {
-            $type = null;
-            $parts = [];
-
-            foreach ($query as $q) {
-                switch ($q[0]) {
-                    case Type::T_MEDIA_TYPE:
-                        if ($type) {
-                            $type = $this->mergeMediaTypes(
-                                $type,
-                                array_map([$this, 'compileValue'], array_slice($q, 1))
-                            );
-
-                            if (empty($type)) { // merge failed
-                                return null;
-                            }
-                        } else {
-                            $type = array_map([$this, 'compileValue'], array_slice($q, 1));
-                        }
-                        break;
-
-                    case Type::T_MEDIA_EXPRESSION:
-                        if (isset($q[2])) {
-                            $parts[] = '('
-                                . $this->compileValue($q[1])
-                                . $this->formatter->assignSeparator
-                                . $this->compileValue($q[2])
-                                . ')';
-                        } else {
-                            $parts[] = '('
-                                . $this->compileValue($q[1])
-                                . ')';
-                        }
-                        break;
-
-                    case Type::T_MEDIA_VALUE:
-                        $parts[] = $this->compileValue($q[1]);
-                        break;
-                }
-            }
-
-            if ($type) {
-                array_unshift($parts, implode(' ', array_filter($type)));
-            }
-
-            if (! empty($parts)) {
-                if ($first) {
-                    $first = false;
-                    $out .= ' ';
-                } else {
-                    $out .= $this->formatter->tagSeparator;
-                }
-
-                $out .= implode(' and ', $parts);
-            }
-        }
-
-        return $out;
-    }
-
-    protected function mergeDirectRelationships($selectors1, $selectors2)
-    {
-        if (empty($selectors1) || empty($selectors2)) {
-            return array_merge($selectors1, $selectors2);
-        }
-
-        $part1 = end($selectors1);
-        $part2 = end($selectors2);
-
-        if (! $this->isImmediateRelationshipCombinator($part1[0]) || $part1 !== $part2) {
-            return array_merge($selectors1, $selectors2);
-        }
-
-        $merged = [];
-
-        do {
-            $part1 = array_pop($selectors1);
-            $part2 = array_pop($selectors2);
-
-            if ($this->isImmediateRelationshipCombinator($part1[0]) && $part1 !== $part2) {
-                $merged = array_merge($selectors1, [$part1], $selectors2, [$part2], $merged);
-                break;
-            }
-
-            array_unshift($merged, $part1);
-            array_unshift($merged, [array_pop($selectors1)[0] . array_pop($selectors2)[0]]);
-        } while (! empty($selectors1) && ! empty($selectors2));
-
-        return $merged;
-    }
-
-    /**
-     * Merge media types
-     *
-     * @param array $type1
-     * @param array $type2
-     *
-     * @return array|null
-     */
-    protected function mergeMediaTypes($type1, $type2)
-    {
-        if (empty($type1)) {
-            return $type2;
-        }
-
-        if (empty($type2)) {
-            return $type1;
-        }
-
-        $m1 = '';
-        $t1 = '';
-
-        if (count($type1) > 1) {
-            $m1= strtolower($type1[0]);
-            $t1= strtolower($type1[1]);
-        } else {
-            $t1 = strtolower($type1[0]);
-        }
-
-        $m2 = '';
-        $t2 = '';
-
-        if (count($type2) > 1) {
-            $m2 = strtolower($type2[0]);
-            $t2 = strtolower($type2[1]);
-        } else {
-            $t2 = strtolower($type2[0]);
-        }
-
-        if (($m1 === Type::T_NOT) ^ ($m2 === Type::T_NOT)) {
-            if ($t1 === $t2) {
-                return null;
-            }
-
-            return [
-                $m1 === Type::T_NOT ? $m2 : $m1,
-                $m1 === Type::T_NOT ? $t2 : $t1,
-            ];
-        }
-
-        if ($m1 === Type::T_NOT && $m2 === Type::T_NOT) {
-            // CSS has no way of representing "neither screen nor print"
-            if ($t1 !== $t2) {
-                return null;
-            }
-
-            return [Type::T_NOT, $t1];
-        }
-
-        if ($t1 !== $t2) {
-            return null;
-        }
-
-        // t1 == t2, neither m1 nor m2 are "not"
-        return [empty($m1)? $m2 : $m1, $t1];
-    }
-
-    /**
-     * Compile import; returns true if the value was something that could be imported
-     *
-     * @param array   $rawPath
-     * @param array   $out
-     * @param boolean $once
-     *
-     * @return boolean
-     */
-    protected function compileImport($rawPath, $out, $once = false)
-    {
-        if ($rawPath[0] === Type::T_STRING) {
-            $path = $this->compileStringContent($rawPath);
-
-            if ($path = $this->findImport($path)) {
-                if (! $once || ! in_array($path, $this->importedFiles)) {
-                    $this->importFile($path, $out);
-                    $this->importedFiles[] = $path;
-                }
-
-                return true;
-            }
-
-            return false;
-        }
-
-        if ($rawPath[0] === Type::T_LIST) {
-            // handle a list of strings
-            if (count($rawPath[2]) === 0) {
-                return false;
-            }
-
-            foreach ($rawPath[2] as $path) {
-                if ($path[0] !== Type::T_STRING) {
-                    return false;
-                }
-            }
-
-            foreach ($rawPath[2] as $path) {
-                $this->compileImport($path, $out);
-            }
-
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Compile child; returns a value to halt execution
-     *
-     * @param array                                $child
-     * @param \Leafo\ScssPhp\Formatter\OutputBlock $out
-     *
-     * @return array
-     */
-    protected function compileChild($child, OutputBlock $out)
-    {
-        $this->sourceIndex  = isset($child[Parser::SOURCE_INDEX]) ? $child[Parser::SOURCE_INDEX] : null;
-        $this->sourceLine   = isset($child[Parser::SOURCE_LINE]) ? $child[Parser::SOURCE_LINE] : -1;
-        $this->sourceColumn = isset($child[Parser::SOURCE_COLUMN]) ? $child[Parser::SOURCE_COLUMN] : -1;
-
-        switch ($child[0]) {
-            case Type::T_SCSSPHP_IMPORT_ONCE:
-                list(, $rawPath) = $child;
-
-                $rawPath = $this->reduce($rawPath);
-
-                if (! $this->compileImport($rawPath, $out, true)) {
-                    $out->lines[] = '@import ' . $this->compileValue($rawPath) . ';';
-                }
-                break;
-
-            case Type::T_IMPORT:
-                list(, $rawPath) = $child;
-
-                $rawPath = $this->reduce($rawPath);
-
-                if (! $this->compileImport($rawPath, $out)) {
-                    $out->lines[] = '@import ' . $this->compileValue($rawPath) . ';';
-                }
-                break;
-
-            case Type::T_DIRECTIVE:
-                $this->compileDirective($child[1]);
-                break;
-
-            case Type::T_AT_ROOT:
-                $this->compileAtRoot($child[1]);
-                break;
-
-            case Type::T_MEDIA:
-                $this->compileMedia($child[1]);
-                break;
-
-            case Type::T_BLOCK:
-                $this->compileBlock($child[1]);
-                break;
-
-            case Type::T_CHARSET:
-                if (! $this->charsetSeen) {
-                    $this->charsetSeen = true;
-
-                    $out->lines[] = '@charset ' . $this->compileValue($child[1]) . ';';
-                }
-                break;
-
-            case Type::T_ASSIGN:
-                list(, $name, $value) = $child;
-
-                if ($name[0] === Type::T_VARIABLE) {
-                    $flags = isset($child[3]) ? $child[3] : [];
-                    $isDefault = in_array('!default', $flags);
-                    $isGlobal = in_array('!global', $flags);
-
-                    if ($isGlobal) {
-                        $this->set($name[1], $this->reduce($value), false, $this->rootEnv);
-                        break;
-                    }
-
-                    $shouldSet = $isDefault &&
-                        (($result = $this->get($name[1], false)) === null
-                        || $result === static::$null);
-
-                    if (! $isDefault || $shouldSet) {
-                        $this->set($name[1], $this->reduce($value));
-                    }
-                    break;
-                }
-
-                $compiledName = $this->compileValue($name);
-
-                // handle shorthand syntax: size / line-height
-                if ($compiledName === 'font') {
-                    if ($value[0] === Type::T_EXPRESSION && $value[1] === '/') {
-                        $value = $this->expToString($value);
-                    } elseif ($value[0] === Type::T_LIST) {
-                        foreach ($value[2] as &$item) {
-                            if ($item[0] === Type::T_EXPRESSION && $item[1] === '/') {
-                                $item = $this->expToString($item);
-                            }
-                        }
-                    }
-                }
-
-                // if the value reduces to null from something else then
-                // the property should be discarded
-                if ($value[0] !== Type::T_NULL) {
-                    $value = $this->reduce($value);
-
-                    if ($value[0] === Type::T_NULL || $value === static::$nullString) {
-                        break;
-                    }
-                }
-
-                $compiledValue = $this->compileValue($value);
-
-                $out->lines[] = $this->formatter->property(
-                    $compiledName,
-                    $compiledValue
-                );
-                break;
-
-            case Type::T_COMMENT:
-                if ($out->type === Type::T_ROOT) {
-                    $this->compileComment($child);
-                    break;
-                }
-
-                $out->lines[] = $child[1];
-                break;
-
-            case Type::T_MIXIN:
-            case Type::T_FUNCTION:
-                list(, $block) = $child;
-
-                $this->set(static::$namespaces[$block->type] . $block->name, $block);
-                break;
-
-            case Type::T_EXTEND:
-                list(, $selectors) = $child;
-
-                foreach ($selectors as $sel) {
-                    $results = $this->evalSelectors([$sel]);
-
-                    foreach ($results as $result) {
-                        // only use the first one
-                        $result = current($result);
-
-                        $this->pushExtends($result, $out->selectors, $child);
-                    }
-                }
-                break;
-
-            case Type::T_IF:
-                list(, $if) = $child;
-
-                if ($this->isTruthy($this->reduce($if->cond, true))) {
-                    return $this->compileChildren($if->children, $out);
-                }
-
-                foreach ($if->cases as $case) {
-                    if ($case->type === Type::T_ELSE ||
-                        $case->type === Type::T_ELSEIF && $this->isTruthy($this->reduce($case->cond))
-                    ) {
-                        return $this->compileChildren($case->children, $out);
-                    }
-                }
-                break;
-
-            case Type::T_EACH:
-                list(, $each) = $child;
-
-                $list = $this->coerceList($this->reduce($each->list));
-
-                $this->pushEnv();
-
-                foreach ($list[2] as $item) {
-                    if (count($each->vars) === 1) {
-                        $this->set($each->vars[0], $item, true);
-                    } else {
-                        list(,, $values) = $this->coerceList($item);
-
-                        foreach ($each->vars as $i => $var) {
-                            $this->set($var, isset($values[$i]) ? $values[$i] : static::$null, true);
-                        }
-                    }
-
-                    $ret = $this->compileChildren($each->children, $out);
-
-                    if ($ret) {
-                        if ($ret[0] !== Type::T_CONTROL) {
-                            $this->popEnv();
-
-                            return $ret;
-                        }
-
-                        if ($ret[1]) {
-                            break;
-                        }
-                    }
-                }
-
-                $this->popEnv();
-                break;
-
-            case Type::T_WHILE:
-                list(, $while) = $child;
-
-                while ($this->isTruthy($this->reduce($while->cond, true))) {
-                    $ret = $this->compileChildren($while->children, $out);
-
-                    if ($ret) {
-                        if ($ret[0] !== Type::T_CONTROL) {
-                            return $ret;
-                        }
-
-                        if ($ret[1]) {
-                            break;
-                        }
-                    }
-                }
-                break;
-
-            case Type::T_FOR:
-                list(, $for) = $child;
-
-                $start = $this->reduce($for->start, true);
-                $end   = $this->reduce($for->end, true);
-
-                if (! ($start[2] == $end[2] || $end->unitless())) {
-                    $this->throwError('Incompatible units: "%s" and "%s".', $start->unitStr(), $end->unitStr());
-
-                    break;
-                }
-
-                $unit  = $start[2];
-                $start = $start[1];
-                $end   = $end[1];
-
-                $d = $start < $end ? 1 : -1;
-
-                for (;;) {
-                    if ((! $for->until && $start - $d == $end) ||
-                        ($for->until && $start == $end)
-                    ) {
-                        break;
-                    }
-
-                    $this->set($for->var, new Node\Number($start, $unit));
-                    $start += $d;
-
-                    $ret = $this->compileChildren($for->children, $out);
-
-                    if ($ret) {
-                        if ($ret[0] !== Type::T_CONTROL) {
-                            return $ret;
-                        }
-
-                        if ($ret[1]) {
-                            break;
-                        }
-                    }
-                }
-                break;
-
-            case Type::T_BREAK:
-                return [Type::T_CONTROL, true];
-
-            case Type::T_CONTINUE:
-                return [Type::T_CONTROL, false];
-
-            case Type::T_RETURN:
-                return $this->reduce($child[1], true);
-
-            case Type::T_NESTED_PROPERTY:
-                list(, $prop) = $child;
-
-                $prefixed = [];
-                $prefix = $this->compileValue($prop->prefix) . '-';
-
-                foreach ($prop->children as $child) {
-                    switch ($child[0]) {
-                        case Type::T_ASSIGN:
-                            array_unshift($child[1][2], $prefix);
-                            break;
-
-                        case Type::T_NESTED_PROPERTY:
-                            array_unshift($child[1]->prefix[2], $prefix);
-                            break;
-                    }
-
-                    $prefixed[] = $child;
-                }
-
-                $this->compileChildrenNoReturn($prefixed, $out);
-                break;
-
-            case Type::T_INCLUDE:
-                // including a mixin
-                list(, $name, $argValues, $content) = $child;
-
-                $mixin = $this->get(static::$namespaces['mixin'] . $name, false);
-
-                if (! $mixin) {
-                    $this->throwError("Undefined mixin $name");
-                    break;
-                }
-
-                $callingScope = $this->getStoreEnv();
-
-                // push scope, apply args
-                $this->pushEnv();
-                $this->env->depth--;
-
-                $storeEnv = $this->storeEnv;
-                $this->storeEnv = $this->env;
-
-                if (isset($content)) {
-                    $content->scope = $callingScope;
-
-                    $this->setRaw(static::$namespaces['special'] . 'content', $content, $this->env);
-                }
-
-                if (isset($mixin->args)) {
-                    $this->applyArguments($mixin->args, $argValues);
-                }
-
-                $this->env->marker = 'mixin';
-
-                $this->compileChildrenNoReturn($mixin->children, $out);
-
-                $this->storeEnv = $storeEnv;
-
-                $this->popEnv();
-                break;
-
-            case Type::T_MIXIN_CONTENT:
-                $content = $this->get(static::$namespaces['special'] . 'content', false, $this->getStoreEnv())
-                         ?: $this->get(static::$namespaces['special'] . 'content', false, $this->env);
-
-                if (! $content) {
-                    $content = new \stdClass();
-                    $content->scope = new \stdClass();
-                    $content->children = $this->storeEnv->parent->block->children;
-                    break;
-                }
-
-                $storeEnv = $this->storeEnv;
-                $this->storeEnv = $content->scope;
-
-                $this->compileChildrenNoReturn($content->children, $out);
-
-                $this->storeEnv = $storeEnv;
-                break;
-
-            case Type::T_DEBUG:
-                list(, $value) = $child;
-
-                $line = $this->sourceLine;
-                $value = $this->compileValue($this->reduce($value, true));
-                fwrite($this->stderr, "Line $line DEBUG: $value\n");
-                break;
-
-            case Type::T_WARN:
-                list(, $value) = $child;
-
-                $line = $this->sourceLine;
-                $value = $this->compileValue($this->reduce($value, true));
-                fwrite($this->stderr, "Line $line WARN: $value\n");
-                break;
-
-            case Type::T_ERROR:
-                list(, $value) = $child;
-
-                $line = $this->sourceLine;
-                $value = $this->compileValue($this->reduce($value, true));
-                $this->throwError("Line $line ERROR: $value\n");
-                break;
-
-            case Type::T_CONTROL:
-                $this->throwError('@break/@continue not permitted in this scope');
-                break;
-
-            default:
-                $this->throwError("unknown child type: $child[0]");
-        }
-    }
-
-    /**
-     * Reduce expression to string
-     *
-     * @param array $exp
-     *
-     * @return array
-     */
-    protected function expToString($exp)
-    {
-        list(, $op, $left, $right, /* $inParens */, $whiteLeft, $whiteRight) = $exp;
-
-        $content = [$this->reduce($left)];
-
-        if ($whiteLeft) {
-            $content[] = ' ';
-        }
-
-        $content[] = $op;
-
-        if ($whiteRight) {
-            $content[] = ' ';
-        }
-
-        $content[] = $this->reduce($right);
-
-        return [Type::T_STRING, '', $content];
-    }
-
-    /**
-     * Is truthy?
-     *
-     * @param array $value
-     *
-     * @return array
-     */
-    protected function isTruthy($value)
-    {
-        return $value !== static::$false && $value !== static::$null;
-    }
-
-    /**
-     * Is the value a direct relationship combinator?
-     *
-     * @param string $value
-     *
-     * @return boolean
-     */
-    protected function isImmediateRelationshipCombinator($value)
-    {
-        return $value === '>' || $value === '+' || $value === '~';
-    }
-
-    /**
-     * Should $value cause its operand to eval
-     *
-     * @param array $value
-     *
-     * @return boolean
-     */
-    protected function shouldEval($value)
-    {
-        switch ($value[0]) {
-            case Type::T_EXPRESSION:
-                if ($value[1] === '/') {
-                    return $this->shouldEval($value[2], $value[3]);
-                }
-
-                // fall-thru
-            case Type::T_VARIABLE:
-            case Type::T_FUNCTION_CALL:
-                return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Reduce value
-     *
-     * @param array   $value
-     * @param boolean $inExp
-     *
-     * @return array|\Leafo\ScssPhp\Node\Number
-     */
-    protected function reduce($value, $inExp = false)
-    {
-        list($type) = $value;
-
-        switch ($type) {
-            case Type::T_EXPRESSION:
-                list(, $op, $left, $right, $inParens) = $value;
-
-                $opName = isset(static::$operatorNames[$op]) ? static::$operatorNames[$op] : $op;
-                $inExp = $inExp || $this->shouldEval($left) || $this->shouldEval($right);
-
-                $left = $this->reduce($left, true);
-
-                if ($op !== 'and' && $op !== 'or') {
-                    $right = $this->reduce($right, true);
-                }
-
-                // special case: looks like css shorthand
-                if ($opName == 'div' && ! $inParens && ! $inExp && isset($right[2])
-                    && (($right[0] !== Type::T_NUMBER && $right[2] != '')
-                    || ($right[0] === Type::T_NUMBER && ! $right->unitless()))
-                ) {
-                    return $this->expToString($value);
-                }
-
-                $left = $this->coerceForExpression($left);
-                $right = $this->coerceForExpression($right);
-
-                $ltype = $left[0];
-                $rtype = $right[0];
-
-                $ucOpName = ucfirst($opName);
-                $ucLType  = ucfirst($ltype);
-                $ucRType  = ucfirst($rtype);
-
-                // this tries:
-                // 1. op[op name][left type][right type]
-                // 2. op[left type][right type] (passing the op as first arg
-                // 3. op[op name]
-                $fn = "op${ucOpName}${ucLType}${ucRType}";
-
-                if (is_callable([$this, $fn]) ||
-                    (($fn = "op${ucLType}${ucRType}") &&
-                        is_callable([$this, $fn]) &&
-                        $passOp = true) ||
-                    (($fn = "op${ucOpName}") &&
-                        is_callable([$this, $fn]) &&
-                        $genOp = true)
-                ) {
-                    $coerceUnit = false;
-
-                    if (! isset($genOp) &&
-                        $left[0] === Type::T_NUMBER && $right[0] === Type::T_NUMBER
-                    ) {
-                        $coerceUnit = true;
-
-                        switch ($opName) {
-                            case 'mul':
-                                $targetUnit = $left[2];
-
-                                foreach ($right[2] as $unit => $exp) {
-                                    $targetUnit[$unit] = (isset($targetUnit[$unit]) ? $targetUnit[$unit] : 0) + $exp;
-                                }
-                                break;
-
-                            case 'div':
-                                $targetUnit = $left[2];
-
-                                foreach ($right[2] as $unit => $exp) {
-                                    $targetUnit[$unit] = (isset($targetUnit[$unit]) ? $targetUnit[$unit] : 0) - $exp;
-                                }
-                                break;
-
-                            case 'mod':
-                                $targetUnit = $left[2];
-                                break;
-
-                            default:
-                                $targetUnit = $left->unitless() ? $right[2] : $left[2];
-                        }
-
-                        if (! $left->unitless() && ! $right->unitless()) {
-                            $left = $left->normalize();
-                            $right = $right->normalize();
-                        }
-                    }
-
-                    $shouldEval = $inParens || $inExp;
-
-                    if (isset($passOp)) {
-                        $out = $this->$fn($op, $left, $right, $shouldEval);
-                    } else {
-                        $out = $this->$fn($left, $right, $shouldEval);
-                    }
-
-                    if (isset($out)) {
-                        if ($coerceUnit && $out[0] === Type::T_NUMBER) {
-                            $out = $out->coerce($targetUnit);
-                        }
-
-                        return $out;
-                    }
-                }
-
-                return $this->expToString($value);
-
-            case Type::T_UNARY:
-                list(, $op, $exp, $inParens) = $value;
-
-                $inExp = $inExp || $this->shouldEval($exp);
-                $exp = $this->reduce($exp);
-
-                if ($exp[0] === Type::T_NUMBER) {
-                    switch ($op) {
-                        case '+':
-                            return new Node\Number($exp[1], $exp[2]);
-
-                        case '-':
-                            return new Node\Number(-$exp[1], $exp[2]);
-                    }
-                }
-
-                if ($op === 'not') {
-                    if ($inExp || $inParens) {
-                        if ($exp === static::$false || $exp === static::$null) {
-                            return static::$true;
-                        }
-
-                        return static::$false;
-                    }
-
-                    $op = $op . ' ';
-                }
-
-                return [Type::T_STRING, '', [$op, $exp]];
-
-            case Type::T_VARIABLE:
-                list(, $name) = $value;
-
-                return $this->reduce($this->get($name));
-
-            case Type::T_LIST:
-                foreach ($value[2] as &$item) {
-                    $item = $this->reduce($item);
-                }
-
-                return $value;
-
-            case Type::T_MAP:
-                foreach ($value[1] as &$item) {
-                    $item = $this->reduce($item);
-                }
-
-                foreach ($value[2] as &$item) {
-                    $item = $this->reduce($item);
-                }
-
-                return $value;
-
-            case Type::T_STRING:
-                foreach ($value[2] as &$item) {
-                    if (is_array($item) || $item instanceof \ArrayAccess) {
-                        $item = $this->reduce($item);
-                    }
-                }
-
-                return $value;
-
-            case Type::T_INTERPOLATE:
-                $value[1] = $this->reduce($value[1]);
-
-                return $value;
-
-            case Type::T_FUNCTION_CALL:
-                list(, $name, $argValues) = $value;
-
-                return $this->fncall($name, $argValues);
-
-            default:
-                return $value;
-        }
-    }
-
-    /**
-     * Function caller
-     *
-     * @param string $name
-     * @param array  $argValues
-     *
-     * @return array|null
-     */
-    private function fncall($name, $argValues)
-    {
-        // SCSS @function
-        if ($this->callScssFunction($name, $argValues, $returnValue)) {
-            return $returnValue;
-        }
-
-        // native PHP functions
-        if ($this->callNativeFunction($name, $argValues, $returnValue)) {
-            return $returnValue;
-        }
-
-        // for CSS functions, simply flatten the arguments into a list
-        $listArgs = [];
-
-        foreach ((array) $argValues as $arg) {
-            if (empty($arg[0])) {
-                $listArgs[] = $this->reduce($arg[1]);
-            }
-        }
-
-        return [Type::T_FUNCTION, $name, [Type::T_LIST, ',', $listArgs]];
-    }
-
-    /**
-     * Normalize name
-     *
-     * @param string $name
-     *
-     * @return string
-     */
-    protected function normalizeName($name)
-    {
-        return str_replace('-', '_', $name);
-    }
-
-    /**
-     * Normalize value
-     *
-     * @param array $value
-     *
-     * @return array
-     */
-    public function normalizeValue($value)
-    {
-        $value = $this->coerceForExpression($this->reduce($value));
-        list($type) = $value;
-
-        switch ($type) {
-            case Type::T_LIST:
-                $value = $this->extractInterpolation($value);
-
-                if ($value[0] !== Type::T_LIST) {
-                    return [Type::T_KEYWORD, $this->compileValue($value)];
-                }
-
-                foreach ($value[2] as $key => $item) {
-                    $value[2][$key] = $this->normalizeValue($item);
-                }
-
-                return $value;
-
-            case Type::T_STRING:
-                return [$type, '"', [$this->compileStringContent($value)]];
-
-            case Type::T_NUMBER:
-                return $value->normalize();
-
-            case Type::T_INTERPOLATE:
-                return [Type::T_KEYWORD, $this->compileValue($value)];
-
-            default:
-                return $value;
-        }
-    }
-
-    /**
-     * Add numbers
-     *
-     * @param array $left
-     * @param array $right
-     *
-     * @return \Leafo\ScssPhp\Node\Number
-     */
-    protected function opAddNumberNumber($left, $right)
-    {
-        return new Node\Number($left[1] + $right[1], $left[2]);
-    }
-
-    /**
-     * Multiply numbers
-     *
-     * @param array $left
-     * @param array $right
-     *
-     * @return \Leafo\ScssPhp\Node\Number
-     */
-    protected function opMulNumberNumber($left, $right)
-    {
-        return new Node\Number($left[1] * $right[1], $left[2]);
-    }
-
-    /**
-     * Subtract numbers
-     *
-     * @param array $left
-     * @param array $right
-     *
-     * @return \Leafo\ScssPhp\Node\Number
-     */
-    protected function opSubNumberNumber($left, $right)
-    {
-        return new Node\Number($left[1] - $right[1], $left[2]);
-    }
-
-    /**
-     * Divide numbers
-     *
-     * @param array $left
-     * @param array $right
-     *
-     * @return array|\Leafo\ScssPhp\Node\Number
-     */
-    protected function opDivNumberNumber($left, $right)
-    {
-        if ($right[1] == 0) {
-            return [Type::T_STRING, '', [$left[1] . $left[2] . '/' . $right[1] . $right[2]]];
-        }
-
-        return new Node\Number($left[1] / $right[1], $left[2]);
-    }
-
-    /**
-     * Mod numbers
-     *
-     * @param array $left
-     * @param array $right
-     *
-     * @return \Leafo\ScssPhp\Node\Number
-     */
-    protected function opModNumberNumber($left, $right)
-    {
-        return new Node\Number($left[1] % $right[1], $left[2]);
-    }
-
-    /**
-     * Add strings
-     *
-     * @param array $left
-     * @param array $right
-     *
-     * @return array
-     */
-    protected function opAdd($left, $right)
-    {
-        if ($strLeft = $this->coerceString($left)) {
-            if ($right[0] === Type::T_STRING) {
-                $right[1] = '';
-            }
-
-            $strLeft[2][] = $right;
-
-            return $strLeft;
-        }
-
-        if ($strRight = $this->coerceString($right)) {
-            if ($left[0] === Type::T_STRING) {
-                $left[1] = '';
-            }
-
-            array_unshift($strRight[2], $left);
-
-            return $strRight;
-        }
-    }
-
-    /**
-     * Boolean and
-     *
-     * @param array   $left
-     * @param array   $right
-     * @param boolean $shouldEval
-     *
-     * @return array
-     */
-    protected function opAnd($left, $right, $shouldEval)
-    {
-        if (! $shouldEval) {
-            return;
-        }
-
-        if ($left !== static::$false and $left !== static::$null) {
-            return $this->reduce($right, true);
-        }
-
-        return $left;
-    }
-
-    /**
-     * Boolean or
-     *
-     * @param array   $left
-     * @param array   $right
-     * @param boolean $shouldEval
-     *
-     * @return array
-     */
-    protected function opOr($left, $right, $shouldEval)
-    {
-        if (! $shouldEval) {
-            return;
-        }
-
-        if ($left !== static::$false and $left !== static::$null) {
-            return $left;
-        }
-
-        return $this->reduce($right, true);
-    }
-
-    /**
-     * Compare colors
-     *
-     * @param string $op
-     * @param array  $left
-     * @param array  $right
-     *
-     * @return array
-     */
-    protected function opColorColor($op, $left, $right)
-    {
-        $out = [Type::T_COLOR];
-
-        foreach ([1, 2, 3] as $i) {
-            $lval = isset($left[$i]) ? $left[$i] : 0;
-            $rval = isset($right[$i]) ? $right[$i] : 0;
-
-            switch ($op) {
-                case '+':
-                    $out[] = $lval + $rval;
-                    break;
-
-                case '-':
-                    $out[] = $lval - $rval;
-                    break;
-
-                case '*':
-                    $out[] = $lval * $rval;
-                    break;
-
-                case '%':
-                    $out[] = $lval % $rval;
-                    break;
-
-                case '/':
-                    if ($rval == 0) {
-                        $this->throwError("color: Can't divide by zero");
-                        break 2;
-                    }
-
-                    $out[] = (int) ($lval / $rval);
-                    break;
-
-                case '==':
-                    return $this->opEq($left, $right);
-
-                case '!=':
-                    return $this->opNeq($left, $right);
-
-                default:
-                    $this->throwError("color: unknown op $op");
-                    break 2;
-            }
-        }
-
-        if (isset($left[4])) {
-            $out[4] = $left[4];
-        } elseif (isset($right[4])) {
-            $out[4] = $right[4];
-        }
-
-        return $this->fixColor($out);
-    }
-
-    /**
-     * Compare color and number
-     *
-     * @param string $op
-     * @param array  $left
-     * @param array  $right
-     *
-     * @return array
-     */
-    protected function opColorNumber($op, $left, $right)
-    {
-        $value = $right[1];
-
-        return $this->opColorColor(
-            $op,
-            $left,
-            [Type::T_COLOR, $value, $value, $value]
-        );
-    }
-
-    /**
-     * Compare number and color
-     *
-     * @param string $op
-     * @param array  $left
-     * @param array  $right
-     *
-     * @return array
-     */
-    protected function opNumberColor($op, $left, $right)
-    {
-        $value = $left[1];
-
-        return $this->opColorColor(
-            $op,
-            [Type::T_COLOR, $value, $value, $value],
-            $right
-        );
-    }
-
-    /**
-     * Compare number1 == number2
-     *
-     * @param array $left
-     * @param array $right
-     *
-     * @return array
-     */
-    protected function opEq($left, $right)
-    {
-        if (($lStr = $this->coerceString($left)) && ($rStr = $this->coerceString($right))) {
-            $lStr[1] = '';
-            $rStr[1] = '';
-
-            $left = $this->compileValue($lStr);
-            $right = $this->compileValue($rStr);
-        }
-
-        return $this->toBool($left === $right);
-    }
-
-    /**
-     * Compare number1 != number2
-     *
-     * @param array $left
-     * @param array $right
-     *
-     * @return array
-     */
-    protected function opNeq($left, $right)
-    {
-        if (($lStr = $this->coerceString($left)) && ($rStr = $this->coerceString($right))) {
-            $lStr[1] = '';
-            $rStr[1] = '';
-
-            $left = $this->compileValue($lStr);
-            $right = $this->compileValue($rStr);
-        }
-
-        return $this->toBool($left !== $right);
-    }
-
-    /**
-     * Compare number1 >= number2
-     *
-     * @param array $left
-     * @param array $right
-     *
-     * @return array
-     */
-    protected function opGteNumberNumber($left, $right)
-    {
-        return $this->toBool($left[1] >= $right[1]);
-    }
-
-    /**
-     * Compare number1 > number2
-     *
-     * @param array $left
-     * @param array $right
-     *
-     * @return array
-     */
-    protected function opGtNumberNumber($left, $right)
-    {
-        return $this->toBool($left[1] > $right[1]);
-    }
-
-    /**
-     * Compare number1 <= number2
-     *
-     * @param array $left
-     * @param array $right
-     *
-     * @return array
-     */
-    protected function opLteNumberNumber($left, $right)
-    {
-        return $this->toBool($left[1] <= $right[1]);
-    }
-
-    /**
-     * Compare number1 < number2
-     *
-     * @param array $left
-     * @param array $right
-     *
-     * @return array
-     */
-    protected function opLtNumberNumber($left, $right)
-    {
-        return $this->toBool($left[1] < $right[1]);
-    }
-
-    /**
-     * Three-way comparison, aka spaceship operator
-     *
-     * @param array $left
-     * @param array $right
-     *
-     * @return \Leafo\ScssPhp\Node\Number
-     */
-    protected function opCmpNumberNumber($left, $right)
-    {
-        $n = $left[1] - $right[1];
-
-        return new Node\Number($n ? $n / abs($n) : 0, '');
-    }
-
-    /**
-     * Cast to boolean
-     *
-     * @api
-     *
-     * @param mixed $thing
-     *
-     * @return array
-     */
-    public function toBool($thing)
-    {
-        return $thing ? static::$true : static::$false;
-    }
-
-    /**
-     * Compiles a primitive value into a CSS property value.
-     *
-     * Values in scssphp are typed by being wrapped in arrays, their format is
-     * typically:
-     *
-     *     array(type, contents [, additional_contents]*)
-     *
-     * The input is expected to be reduced. This function will not work on
-     * things like expressions and variables.
-     *
-     * @api
-     *
-     * @param array $value
-     *
-     * @return string
-     */
-    public function compileValue($value)
-    {
-        $value = $this->reduce($value);
-
-        list($type) = $value;
-
-        switch ($type) {
-            case Type::T_KEYWORD:
-                return $value[1];
-
-            case Type::T_COLOR:
-                // [1] - red component (either number for a %)
-                // [2] - green component
-                // [3] - blue component
-                // [4] - optional alpha component
-                list(, $r, $g, $b) = $value;
-
-                $r = round($r);
-                $g = round($g);
-                $b = round($b);
-
-                if (count($value) === 5 && $value[4] !== 1) { // rgba
-                    return 'rgba(' . $r . ', ' . $g . ', ' . $b . ', ' . $value[4] . ')';
-                }
-
-                $h = sprintf('#%02x%02x%02x', $r, $g, $b);
-
-                // Converting hex color to short notation (e.g. #003399 to #039)
-                if ($h[1] === $h[2] && $h[3] === $h[4] && $h[5] === $h[6]) {
-                    $h = '#' . $h[1] . $h[3] . $h[5];
-                }
-
-                return $h;
-
-            case Type::T_NUMBER:
-                return $value->output($this);
-
-            case Type::T_STRING:
-                return $value[1] . $this->compileStringContent($value) . $value[1];
-
-            case Type::T_FUNCTION:
-                $args = ! empty($value[2]) ? $this->compileValue($value[2]) : '';
-
-                return "$value[1]($args)";
-
-            case Type::T_LIST:
-                $value = $this->extractInterpolation($value);
-
-                if ($value[0] !== Type::T_LIST) {
-                    return $this->compileValue($value);
-                }
-
-                list(, $delim, $items) = $value;
-
-                if ($delim !== ' ') {
-                    $delim .= ' ';
-                }
-
-                $filtered = [];
-
-                foreach ($items as $item) {
-                    if ($item[0] === Type::T_NULL) {
-                        continue;
-                    }
-
-                    $filtered[] = $this->compileValue($item);
-                }
-
-                return implode("$delim", $filtered);
-
-            case Type::T_MAP:
-                $keys = $value[1];
-                $values = $value[2];
-                $filtered = [];
-
-                for ($i = 0, $s = count($keys); $i < $s; $i++) {
-                    $filtered[$this->compileValue($keys[$i])] = $this->compileValue($values[$i]);
-                }
-
-                array_walk($filtered, function (&$value, $key) {
-                    $value = $key . ': ' . $value;
-                });
-
-                return '(' . implode(', ', $filtered) . ')';
-
-            case Type::T_INTERPOLATED:
-                // node created by extractInterpolation
-                list(, $interpolate, $left, $right) = $value;
-                list(,, $whiteLeft, $whiteRight) = $interpolate;
-
-                $left = count($left[2]) > 0 ?
-                    $this->compileValue($left) . $whiteLeft : '';
-
-                $right = count($right[2]) > 0 ?
-                    $whiteRight . $this->compileValue($right) : '';
-
-                return $left . $this->compileValue($interpolate) . $right;
-
-            case Type::T_INTERPOLATE:
-                // raw parse node
-                list(, $exp) = $value;
-
-                // strip quotes if it's a string
-                $reduced = $this->reduce($exp);
-
-                switch ($reduced[0]) {
-                    case Type::T_LIST:
-                        $reduced = $this->extractInterpolation($reduced);
-
-                        if ($reduced[0] !== Type::T_LIST) {
-                            break;
-                        }
-
-                        list(, $delim, $items) = $reduced;
-
-                        if ($delim !== ' ') {
-                            $delim .= ' ';
-                        }
-
-                        $filtered = [];
-
-                        foreach ($items as $item) {
-                            if ($item[0] === Type::T_NULL) {
-                                continue;
-                            }
-
-                            $temp = $this->compileValue([Type::T_KEYWORD, $item]);
-                            if ($temp[0] === Type::T_STRING) {
-                                $filtered[] = $this->compileStringContent($temp);
-                            } elseif ($temp[0] === Type::T_KEYWORD) {
-                                $filtered[] = $temp[1];
-                            } else {
-                                $filtered[] = $this->compileValue($temp);
-                            }
-                        }
-
-                        $reduced = [Type::T_KEYWORD, implode("$delim", $filtered)];
-                        break;
-
-                    case Type::T_STRING:
-                        $reduced = [Type::T_KEYWORD, $this->compileStringContent($reduced)];
-                        break;
-
-                    case Type::T_NULL:
-                        $reduced = [Type::T_KEYWORD, ''];
-                }
-
-                return $this->compileValue($reduced);
-
-            case Type::T_NULL:
-                return 'null';
-
-            default:
-                $this->throwError("unknown value type: $type");
-        }
-    }
-
-    /**
-     * Flatten list
-     *
-     * @param array $list
-     *
-     * @return string
-     */
-    protected function flattenList($list)
-    {
-        return $this->compileValue($list);
-    }
-
-    /**
-     * Compile string content
-     *
-     * @param array $string
-     *
-     * @return string
-     */
-    protected function compileStringContent($string)
-    {
-        $parts = [];
-
-        foreach ($string[2] as $part) {
-            if (is_array($part) || $part instanceof \ArrayAccess) {
-                $parts[] = $this->compileValue($part);
-            } else {
-                $parts[] = $part;
-            }
-        }
-
-        return implode($parts);
-    }
-
-    /**
-     * Extract interpolation; it doesn't need to be recursive, compileValue will handle that
-     *
-     * @param array $list
-     *
-     * @return array
-     */
-    protected function extractInterpolation($list)
-    {
-        $items = $list[2];
-
-        foreach ($items as $i => $item) {
-            if ($item[0] === Type::T_INTERPOLATE) {
-                $before = [Type::T_LIST, $list[1], array_slice($items, 0, $i)];
-                $after  = [Type::T_LIST, $list[1], array_slice($items, $i + 1)];
-
-                return [Type::T_INTERPOLATED, $item, $before, $after];
-            }
-        }
-
-        return $list;
-    }
-
-    /**
-     * Find the final set of selectors
-     *
-     * @param \Leafo\ScssPhp\Compiler\Environment $env
-     *
-     * @return array
-     */
-    protected function multiplySelectors(Environment $env)
-    {
-        $envs            = $this->compactEnv($env);
-        $selectors       = [];
-        $parentSelectors = [[]];
-
-        while ($env = array_pop($envs)) {
-            if (empty($env->selectors)) {
-                continue;
-            }
-
-            $selectors = [];
-
-            foreach ($env->selectors as $selector) {
-                foreach ($parentSelectors as $parent) {
-                    $selectors[] = $this->joinSelectors($parent, $selector);
-                }
-            }
-
-            $parentSelectors = $selectors;
-        }
-
-        return $selectors;
-    }
-
-    /**
-     * Join selectors; looks for & to replace, or append parent before child
-     *
-     * @param array $parent
-     * @param array $child
-     *
-     * @return array
-     */
-    protected function joinSelectors($parent, $child)
-    {
-        $setSelf = false;
-        $out = [];
-
-        foreach ($child as $part) {
-            $newPart = [];
-
-            foreach ($part as $p) {
-                if ($p === static::$selfSelector) {
-                    $setSelf = true;
-
-                    foreach ($parent as $i => $parentPart) {
-                        if ($i > 0) {
-                            $out[] = $newPart;
-                            $newPart = [];
-                        }
-
-                        foreach ($parentPart as $pp) {
-                            $newPart[] = $pp;
-                        }
-                    }
-                } else {
-                    $newPart[] = $p;
-                }
-            }
-
-            $out[] = $newPart;
-        }
-
-        return $setSelf ? $out : array_merge($parent, $child);
-    }
-
-    /**
-     * Multiply media
-     *
-     * @param \Leafo\ScssPhp\Compiler\Environment $env
-     * @param array                               $childQueries
-     *
-     * @return array
-     */
-    protected function multiplyMedia(Environment $env = null, $childQueries = null)
-    {
-        if (! isset($env) ||
-            ! empty($env->block->type) && $env->block->type !== Type::T_MEDIA
-        ) {
-            return $childQueries;
-        }
-
-        // plain old block, skip
-        if (empty($env->block->type)) {
-            return $this->multiplyMedia($env->parent, $childQueries);
-        }
-
-        $parentQueries = isset($env->block->queryList)
-            ? $env->block->queryList
-            : [[[Type::T_MEDIA_VALUE, $env->block->value]]];
-
-        if ($childQueries === null) {
-            $childQueries = $parentQueries;
-        } else {
-            $originalQueries = $childQueries;
-            $childQueries = [];
-
-            foreach ($parentQueries as $parentQuery) {
-                foreach ($originalQueries as $childQuery) {
-                    $childQueries []= array_merge($parentQuery, $childQuery);
-                }
-            }
-        }
-
-        return $this->multiplyMedia($env->parent, $childQueries);
-    }
-
-    /**
-     * Convert env linked list to stack
-     *
-     * @param \Leafo\ScssPhp\Compiler\Environment $env
-     *
-     * @return array
-     */
-    private function compactEnv(Environment $env)
-    {
-        for ($envs = []; $env; $env = $env->parent) {
-            $envs[] = $env;
-        }
-
-        return $envs;
-    }
-
-    /**
-     * Convert env stack to singly linked list
-     *
-     * @param array $envs
-     *
-     * @return \Leafo\ScssPhp\Compiler\Environment
-     */
-    private function extractEnv($envs)
-    {
-        for ($env = null; $e = array_pop($envs);) {
-            $e->parent = $env;
-            $env = $e;
-        }
-
-        return $env;
-    }
-
-    /**
-     * Push environment
-     *
-     * @param \Leafo\ScssPhp\Block $block
-     *
-     * @return \Leafo\ScssPhp\Compiler\Environment
-     */
-    protected function pushEnv(Block $block = null)
-    {
-        $env = new Environment;
-        $env->parent = $this->env;
-        $env->store  = [];
-        $env->block  = $block;
-        $env->depth  = isset($this->env->depth) ? $this->env->depth + 1 : 0;
-
-        $this->env = $env;
-
-        return $env;
-    }
-
-    /**
-     * Pop environment
-     */
-    protected function popEnv()
-    {
-        $this->env = $this->env->parent;
-    }
-
-    /**
-     * Get store environment
-     *
-     * @return \Leafo\ScssPhp\Compiler\Environment
-     */
-    protected function getStoreEnv()
-    {
-        return isset($this->storeEnv) ? $this->storeEnv : $this->env;
-    }
-
-    /**
-     * Set variable
-     *
-     * @param string                              $name
-     * @param mixed                               $value
-     * @param boolean                             $shadow
-     * @param \Leafo\ScssPhp\Compiler\Environment $env
-     */
-    protected function set($name, $value, $shadow = false, Environment $env = null)
-    {
-        $name = $this->normalizeName($name);
-
-        if (! isset($env)) {
-            $env = $this->getStoreEnv();
-        }
-
-        if ($shadow) {
-            $this->setRaw($name, $value, $env);
-        } else {
-            $this->setExisting($name, $value, $env);
-        }
-    }
-
-    /**
-     * Set existing variable
-     *
-     * @param string                              $name
-     * @param mixed                               $value
-     * @param \Leafo\ScssPhp\Compiler\Environment $env
-     */
-    protected function setExisting($name, $value, Environment $env)
-    {
-        $storeEnv = $env;
-
-        $hasNamespace = $name[0] === '^' || $name[0] === '@' || $name[0] === '%';
-
-        for (;;) {
-            if (array_key_exists($name, $env->store)) {
-                break;
-            }
-
-            if (! $hasNamespace && isset($env->marker)) {
-                $env = $storeEnv;
-                break;
-            }
-
-            if (! isset($env->parent)) {
-                $env = $storeEnv;
-                break;
-            }
-
-            $env = $env->parent;
-        }
-
-        $env->store[$name] = $value;
-    }
-
-    /**
-     * Set raw variable
-     *
-     * @param string                              $name
-     * @param mixed                               $value
-     * @param \Leafo\ScssPhp\Compiler\Environment $env
-     */
-    protected function setRaw($name, $value, Environment $env)
-    {
-        $env->store[$name] = $value;
-    }
-
-    /**
-     * Get variable
-     *
-     * @api
-     *
-     * @param string                              $name
-     * @param boolean                             $shouldThrow
-     * @param \Leafo\ScssPhp\Compiler\Environment $env
-     *
-     * @return mixed
-     */
-    public function get($name, $shouldThrow = true, Environment $env = null)
-    {
-        $normalizedName = $this->normalizeName($name);
-        $specialContentKey = static::$namespaces['special'] . 'content';
-
-        if (! isset($env)) {
-            $env = $this->getStoreEnv();
-        }
-
-        $nextIsRoot = false;
-        $hasNamespace = $normalizedName[0] === '^' || $normalizedName[0] === '@' || $normalizedName[0] === '%';
-
-        for (;;) {
-            if (array_key_exists($normalizedName, $env->store)) {
-                return $env->store[$normalizedName];
-            }
-
-            if (! $hasNamespace && isset($env->marker)) {
-                if (! $nextIsRoot && ! empty($env->store[$specialContentKey])) {
-                    $env = $env->store[$specialContentKey]->scope;
-                    $nextIsRoot = true;
-                    continue;
-                }
-
-                $env = $this->rootEnv;
-                continue;
-            }
-
-            if (! isset($env->parent)) {
-                break;
-            }
-
-            $env = $env->parent;
-        }
-
-        if ($shouldThrow) {
-            $this->throwError("Undefined variable \$$name");
-        }
-
-        // found nothing
-    }
-
-    /**
-     * Has variable?
-     *
-     * @param string                              $name
-     * @param \Leafo\ScssPhp\Compiler\Environment $env
-     *
-     * @return boolean
-     */
-    protected function has($name, Environment $env = null)
-    {
-        return $this->get($name, false, $env) !== null;
-    }
-
-    /**
-     * Inject variables
-     *
-     * @param array $args
-     */
-    protected function injectVariables(array $args)
-    {
-        if (empty($args)) {
-            return;
-        }
-
-        $parser = $this->parserFactory(__METHOD__);
-
-        foreach ($args as $name => $strValue) {
-            if ($name[0] === '$') {
-                $name = substr($name, 1);
-            }
-
-            if (! $parser->parseValue($strValue, $value)) {
-                $value = $this->coerceValue($strValue);
-            }
-
-            $this->set($name, $value);
-        }
-    }
-
-    /**
-     * Set variables
-     *
-     * @api
-     *
-     * @param array $variables
-     */
-    public function setVariables(array $variables)
-    {
-        $this->registeredVars = array_merge($this->registeredVars, $variables);
-    }
-
-    /**
-     * Unset variable
-     *
-     * @api
-     *
-     * @param string $name
-     */
-    public function unsetVariable($name)
-    {
-        unset($this->registeredVars[$name]);
-    }
-
-    /**
-     * Returns list of variables
-     *
-     * @api
-     *
-     * @return array
-     */
-    public function getVariables()
-    {
-        return $this->registeredVars;
-    }
-
-    /**
-     * Adds to list of parsed files
-     *
-     * @api
-     *
-     * @param string $path
-     */
-    public function addParsedFile($path)
-    {
-        if (isset($path) && file_exists($path)) {
-            $this->parsedFiles[realpath($path)] = filemtime($path);
-        }
-    }
-
-    /**
-     * Returns list of parsed files
-     *
-     * @api
-     *
-     * @return array
-     */
-    public function getParsedFiles()
-    {
-        return $this->parsedFiles;
-    }
-
-    /**
-     * Add import path
-     *
-     * @api
-     *
-     * @param string $path
-     */
-    public function addImportPath($path)
-    {
-        if (! in_array($path, $this->importPaths)) {
-            $this->importPaths[] = $path;
-        }
-    }
-
-    /**
-     * Set import paths
-     *
-     * @api
-     *
-     * @param string|array $path
-     */
-    public function setImportPaths($path)
-    {
-        $this->importPaths = (array) $path;
-    }
-
-    /**
-     * Set number precision
-     *
-     * @api
-     *
-     * @param integer $numberPrecision
-     */
-    public function setNumberPrecision($numberPrecision)
-    {
-        Node\Number::$precision = $numberPrecision;
-    }
-
-    /**
-     * Set formatter
-     *
-     * @api
-     *
-     * @param string $formatterName
-     */
-    public function setFormatter($formatterName)
-    {
-        $this->formatter = $formatterName;
-    }
-
-    /**
-     * Set line number style
-     *
-     * @api
-     *
-     * @param string $lineNumberStyle
-     */
-    public function setLineNumberStyle($lineNumberStyle)
-    {
-        $this->lineNumberStyle = $lineNumberStyle;
-    }
-
-    /**
-     * Enable/disable source maps
-     *
-     * @api
-     *
-     * @param integer $sourceMap
-     */
-    public function setSourceMap($sourceMap)
-    {
-        $this->sourceMap = $sourceMap;
-    }
-
-    /**
-     * Set source map options
-     *
-     * @api
-     *
-     * @param array $sourceMapOptions
-     */
-    public function setSourceMapOptions($sourceMapOptions)
-    {
-        $this->sourceMapOptions = $sourceMapOptions;
-    }
-
-    /**
-     * Register function
-     *
-     * @api
-     *
-     * @param string   $name
-     * @param callable $func
-     * @param array    $prototype
-     */
-    public function registerFunction($name, $func, $prototype = null)
-    {
-        $this->userFunctions[$this->normalizeName($name)] = [$func, $prototype];
-    }
-
-    /**
-     * Unregister function
-     *
-     * @api
-     *
-     * @param string $name
-     */
-    public function unregisterFunction($name)
-    {
-        unset($this->userFunctions[$this->normalizeName($name)]);
-    }
-
-    /**
-     * Add feature
-     *
-     * @api
-     *
-     * @param string $name
-     */
-    public function addFeature($name)
-    {
-        $this->registeredFeatures[$name] = true;
-    }
-
-    /**
-     * Import file
-     *
-     * @param string $path
-     * @param array  $out
-     */
-    protected function importFile($path, $out)
-    {
-        // see if tree is cached
-        $realPath = realpath($path);
-
-        if (isset($this->importCache[$realPath])) {
-            $this->handleImportLoop($realPath);
-
-            $tree = $this->importCache[$realPath];
-        } else {
-            $code   = file_get_contents($path);
-            $parser = $this->parserFactory($path);
-            $tree   = $parser->parse($code);
-
-            $this->importCache[$realPath] = $tree;
-        }
-
-        $pi = pathinfo($path);
-        array_unshift($this->importPaths, $pi['dirname']);
-        $this->compileChildrenNoReturn($tree->children, $out);
-        array_shift($this->importPaths);
-    }
-
-    /**
-     * Return the file path for an import url if it exists
-     *
-     * @api
-     *
-     * @param string $url
-     *
-     * @return string|null
-     */
-    public function findImport($url)
-    {
-        $urls = [];
-
-        // for "normal" scss imports (ignore vanilla css and external requests)
-        if (! preg_match('/\.css$|^https?:\/\//', $url)) {
-            // try both normal and the _partial filename
-            $urls = [$url, preg_replace('/[^\/]+$/', '_\0', $url)];
-        }
-
-        $hasExtension = preg_match('/[.]s?css$/', $url);
-
-        foreach ($this->importPaths as $dir) {
-            if (is_string($dir)) {
-                // check urls for normal import paths
-                foreach ($urls as $full) {
-                    $full = $dir
-                        . (! empty($dir) && substr($dir, -1) !== '/' ? '/' : '')
-                        . $full;
-
-                    if ($this->fileExists($file = $full . '.scss') ||
-                        ($hasExtension && $this->fileExists($file = $full))
-                    ) {
-                        return $file;
-                    }
-                }
-            } elseif (is_callable($dir)) {
-                // check custom callback for import path
-                $file = call_user_func($dir, $url);
-
-                if ($file !== null) {
-                    return $file;
-                }
-            }
-        }
-
-        return null;
-    }
-
-    /**
-     * Set encoding
-     *
-     * @api
-     *
-     * @param string $encoding
-     */
-    public function setEncoding($encoding)
-    {
-        $this->encoding = $encoding;
-    }
-
-    /**
-     * Ignore errors?
-     *
-     * @api
-     *
-     * @param boolean $ignoreErrors
-     *
-     * @return \Leafo\ScssPhp\Compiler
-     */
-    public function setIgnoreErrors($ignoreErrors)
-    {
-        $this->ignoreErrors = $ignoreErrors;
-    }
-
-    /**
-     * Throw error (exception)
-     *
-     * @api
-     *
-     * @param string $msg Message with optional sprintf()-style vararg parameters
-     *
-     * @throws \Leafo\ScssPhp\Exception\CompilerException
-     */
-    public function throwError($msg)
-    {
-        if ($this->ignoreErrors) {
-            return;
-        }
-
-        if (func_num_args() > 1) {
-            $msg = call_user_func_array('sprintf', func_get_args());
-        }
-
-        $line = $this->sourceLine;
-        $msg = "$msg: line: $line";
-
-        throw new CompilerException($msg);
-    }
-
-    /**
-     * Handle import loop
-     *
-     * @param string $name
-     *
-     * @throws \Exception
-     */
-    protected function handleImportLoop($name)
-    {
-        for ($env = $this->env; $env; $env = $env->parent) {
-            $file = $this->sourceNames[$env->block->sourceIndex];
-
-            if (realpath($file) === $name) {
-                $this->throwError('An @import loop has been found: %s imports %s', $file, basename($file));
-                break;
-            }
-        }
-    }
-
-    /**
-     * Does file exist?
-     *
-     * @param string $name
-     *
-     * @return boolean
-     */
-    protected function fileExists($name)
-    {
-        return file_exists($name) && is_file($name);
-    }
-
-    /**
-     * Call SCSS @function
-     *
-     * @param string $name
-     * @param array  $argValues
-     * @param array  $returnValue
-     *
-     * @return boolean Returns true if returnValue is set; otherwise, false
-     */
-    protected function callScssFunction($name, $argValues, &$returnValue)
-    {
-        $func = $this->get(static::$namespaces['function'] . $name, false);
-
-        if (! $func) {
-            return false;
-        }
-
-        $this->pushEnv();
-
-        $storeEnv = $this->storeEnv;
-        $this->storeEnv = $this->env;
-
-        // set the args
-        if (isset($func->args)) {
-            $this->applyArguments($func->args, $argValues);
-        }
-
-        // throw away lines and children
-        $tmp = new OutputBlock;
-        $tmp->lines    = [];
-        $tmp->children = [];
-
-        $this->env->marker = 'function';
-
-        $ret = $this->compileChildren($func->children, $tmp);
-
-        $this->storeEnv = $storeEnv;
-
-        $this->popEnv();
-
-        $returnValue = ! isset($ret) ? static::$defaultValue : $ret;
-
-        return true;
-    }
-
-    /**
-     * Call built-in and registered (PHP) functions
-     *
-     * @param string $name
-     * @param array  $args
-     * @param array  $returnValue
-     *
-     * @return boolean Returns true if returnValue is set; otherwise, false
-     */
-    protected function callNativeFunction($name, $args, &$returnValue)
-    {
-        // try a lib function
-        $name = $this->normalizeName($name);
-
-        if (isset($this->userFunctions[$name])) {
-            // see if we can find a user function
-            list($f, $prototype) = $this->userFunctions[$name];
-        } elseif (($f = $this->getBuiltinFunction($name)) && is_callable($f)) {
-            $libName   = $f[1];
-            $prototype = isset(static::$$libName) ? static::$$libName : null;
-        } else {
-            return false;
-        }
-
-        list($sorted, $kwargs) = $this->sortArgs($prototype, $args);
-
-        if ($name !== 'if' && $name !== 'call') {
-            foreach ($sorted as &$val) {
-                $val = $this->reduce($val, true);
-            }
-        }
-
-        $returnValue = call_user_func($f, $sorted, $kwargs);
-
-        if (! isset($returnValue)) {
-            return false;
-        }
-
-        $returnValue = $this->coerceValue($returnValue);
-
-        return true;
-    }
-
-    /**
-     * Get built-in function
-     *
-     * @param string $name Normalized name
-     *
-     * @return array
-     */
-    protected function getBuiltinFunction($name)
-    {
-        $libName = 'lib' . preg_replace_callback(
-            '/_(.)/',
-            function ($m) {
-                return ucfirst($m[1]);
-            },
-            ucfirst($name)
-        );
-
-        return [$this, $libName];
-    }
-
-    /**
-     * Sorts keyword arguments
-     *
-     * @param array $prototype
-     * @param array $args
-     *
-     * @return array
-     */
-    protected function sortArgs($prototype, $args)
-    {
-        $keyArgs = [];
-        $posArgs = [];
-
-        // separate positional and keyword arguments
-        foreach ($args as $arg) {
-            list($key, $value) = $arg;
-
-            $key = $key[1];
-
-            if (empty($key)) {
-                $posArgs[] = $value;
-            } else {
-                $keyArgs[$key] = $value;
-            }
-        }
-
-        if (! isset($prototype)) {
-            return [$posArgs, $keyArgs];
-        }
-
-        // copy positional args
-        $finalArgs = array_pad($posArgs, count($prototype), null);
-
-        // overwrite positional args with keyword args
-        foreach ($prototype as $i => $names) {
-            foreach ((array) $names as $name) {
-                if (isset($keyArgs[$name])) {
-                    $finalArgs[$i] = $keyArgs[$name];
-                }
-            }
-        }
-
-        return [$finalArgs, $keyArgs];
-    }
-
-    /**
-     * Apply argument values per definition
-     *
-     * @param array $argDef
-     * @param array $argValues
-     *
-     * @throws \Exception
-     */
-    protected function applyArguments($argDef, $argValues)
-    {
-        $storeEnv = $this->getStoreEnv();
-
-        $env = new Environment;
-        $env->store = $storeEnv->store;
-
-        $hasVariable = false;
-        $args = [];
-
-        foreach ($argDef as $i => $arg) {
-            list($name, $default, $isVariable) = $argDef[$i];
-
-            $args[$name] = [$i, $name, $default, $isVariable];
-            $hasVariable |= $isVariable;
-        }
-
-        $keywordArgs = [];
-        $deferredKeywordArgs = [];
-        $remaining = [];
-
-        // assign the keyword args
-        foreach ((array) $argValues as $arg) {
-            if (! empty($arg[0])) {
-                if (! isset($args[$arg[0][1]])) {
-                    if ($hasVariable) {
-                        $deferredKeywordArgs[$arg[0][1]] = $arg[1];
-                    } else {
-                        $this->throwError("Mixin or function doesn't have an argument named $%s.", $arg[0][1]);
-                        break;
-                    }
-                } elseif ($args[$arg[0][1]][0] < count($remaining)) {
-                    $this->throwError("The argument $%s was passed both by position and by name.", $arg[0][1]);
-                    break;
-                } else {
-                    $keywordArgs[$arg[0][1]] = $arg[1];
-                }
-            } elseif (count($keywordArgs)) {
-                $this->throwError('Positional arguments must come before keyword arguments.');
-                break;
-            } elseif ($arg[2] === true) {
-                $val = $this->reduce($arg[1], true);
-
-                if ($val[0] === Type::T_LIST) {
-                    foreach ($val[2] as $name => $item) {
-                        if (! is_numeric($name)) {
-                            $keywordArgs[$name] = $item;
-                        } else {
-                            $remaining[] = $item;
-                        }
-                    }
-                } elseif ($val[0] === Type::T_MAP) {
-                    foreach ($val[1] as $i => $name) {
-                        $name = $this->compileStringContent($this->coerceString($name));
-                        $item = $val[2][$i];
-
-                        if (! is_numeric($name)) {
-                            $keywordArgs[$name] = $item;
-                        } else {
-                            $remaining[] = $item;
-                        }
-                    }
-                } else {
-                    $remaining[] = $val;
-                }
-            } else {
-                $remaining[] = $arg[1];
-            }
-        }
-
-        foreach ($args as $arg) {
-            list($i, $name, $default, $isVariable) = $arg;
-
-            if ($isVariable) {
-                $val = [Type::T_LIST, ',', [], $isVariable];
-
-                for ($count = count($remaining); $i < $count; $i++) {
-                    $val[2][] = $remaining[$i];
-                }
-
-                foreach ($deferredKeywordArgs as $itemName => $item) {
-                    $val[2][$itemName] = $item;
-                }
-            } elseif (isset($remaining[$i])) {
-                $val = $remaining[$i];
-            } elseif (isset($keywordArgs[$name])) {
-                $val = $keywordArgs[$name];
-            } elseif (! empty($default)) {
-                continue;
-            } else {
-                $this->throwError("Missing argument $name");
-                break;
-            }
-
-            $this->set($name, $this->reduce($val, true), true, $env);
-        }
-
-        $storeEnv->store = $env->store;
-
-        foreach ($args as $arg) {
-            list($i, $name, $default, $isVariable) = $arg;
-
-            if ($isVariable || isset($remaining[$i]) || isset($keywordArgs[$name]) || empty($default)) {
-                continue;
-            }
-
-            $this->set($name, $this->reduce($default, true), true);
-        }
-    }
-
-    /**
-     * Coerce a php value into a scss one
-     *
-     * @param mixed $value
-     *
-     * @return array|\Leafo\ScssPhp\Node\Number
-     */
-    private function coerceValue($value)
-    {
-        if (is_array($value) || $value instanceof \ArrayAccess) {
-            return $value;
-        }
-
-        if (is_bool($value)) {
-            return $this->toBool($value);
-        }
-
-        if ($value === null) {
-            return static::$null;
-        }
-
-        if (is_numeric($value)) {
-            return new Node\Number($value, '');
-        }
-
-        if ($value === '') {
-            return static::$emptyString;
-        }
-
-        if (preg_match('/^(#([0-9a-f]{6})|#([0-9a-f]{3}))$/i', $value, $m)) {
-            $color = [Type::T_COLOR];
-
-            if (isset($m[3])) {
-                $num = hexdec($m[3]);
-
-                foreach ([3, 2, 1] as $i) {
-                    $t = $num & 0xf;
-                    $color[$i] = $t << 4 | $t;
-                    $num >>= 4;
-                }
-            } else {
-                $num = hexdec($m[2]);
-
-                foreach ([3, 2, 1] as $i) {
-                    $color[$i] = $num & 0xff;
-                    $num >>= 8;
-                }
-            }
-
-            return $color;
-        }
-
-        return [Type::T_KEYWORD, $value];
-    }
-
-    /**
-     * Coerce something to map
-     *
-     * @param array $item
-     *
-     * @return array
-     */
-    protected function coerceMap($item)
-    {
-        if ($item[0] === Type::T_MAP) {
-            return $item;
-        }
-
-        if ($item === static::$emptyList) {
-            return static::$emptyMap;
-        }
-
-        return [Type::T_MAP, [$item], [static::$null]];
-    }
-
-    /**
-     * Coerce something to list
-     *
-     * @param array  $item
-     * @param string $delim
-     *
-     * @return array
-     */
-    protected function coerceList($item, $delim = ',')
-    {
-        if (isset($item) && $item[0] === Type::T_LIST) {
-            return $item;
-        }
-
-        if (isset($item) && $item[0] === Type::T_MAP) {
-            $keys = $item[1];
-            $values = $item[2];
-            $list = [];
-
-            for ($i = 0, $s = count($keys); $i < $s; $i++) {
-                $key = $keys[$i];
-                $value = $values[$i];
-
-                $list[] = [
-                    Type::T_LIST,
-                    '',
-                    [[Type::T_KEYWORD, $this->compileStringContent($this->coerceString($key))], $value]
-                ];
-            }
-
-            return [Type::T_LIST, ',', $list];
-        }
-
-        return [Type::T_LIST, $delim, ! isset($item) ? []: [$item]];
-    }
-
-    /**
-     * Coerce color for expression
-     *
-     * @param array $value
-     *
-     * @return array|null
-     */
-    protected function coerceForExpression($value)
-    {
-        if ($color = $this->coerceColor($value)) {
-            return $color;
-        }
-
-        return $value;
-    }
-
-    /**
-     * Coerce value to color
-     *
-     * @param array $value
-     *
-     * @return array|null
-     */
-    protected function coerceColor($value)
-    {
-        switch ($value[0]) {
-            case Type::T_COLOR:
-                return $value;
-
-            case Type::T_KEYWORD:
-                $name = strtolower($value[1]);
-
-                if (isset(Colors::$cssColors[$name])) {
-                    $rgba = explode(',', Colors::$cssColors[$name]);
-
-                    return isset($rgba[3])
-                        ? [Type::T_COLOR, (int) $rgba[0], (int) $rgba[1], (int) $rgba[2], (int) $rgba[3]]
-                        : [Type::T_COLOR, (int) $rgba[0], (int) $rgba[1], (int) $rgba[2]];
-                }
-
-                return null;
-        }
-
-        return null;
-    }
-
-    /**
-     * Coerce value to string
-     *
-     * @param array $value
-     *
-     * @return array|null
-     */
-    protected function coerceString($value)
-    {
-        if ($value[0] === Type::T_STRING) {
-            return $value;
-        }
-
-        return [Type::T_STRING, '', [$this->compileValue($value)]];
-    }
-
-    /**
-     * Coerce value to a percentage
-     *
-     * @param array $value
-     *
-     * @return integer|float
-     */
-    protected function coercePercent($value)
-    {
-        if ($value[0] === Type::T_NUMBER) {
-            if (! empty($value[2]['%'])) {
-                return $value[1] / 100;
-            }
-
-            return $value[1];
-        }
-
-        return 0;
-    }
-
-    /**
-     * Assert value is a map
-     *
-     * @api
-     *
-     * @param array $value
-     *
-     * @return array
-     *
-     * @throws \Exception
-     */
-    public function assertMap($value)
-    {
-        $value = $this->coerceMap($value);
-
-        if ($value[0] !== Type::T_MAP) {
-            $this->throwError('expecting map');
-        }
-
-        return $value;
-    }
-
-    /**
-     * Assert value is a list
-     *
-     * @api
-     *
-     * @param array $value
-     *
-     * @return array
-     *
-     * @throws \Exception
-     */
-    public function assertList($value)
-    {
-        if ($value[0] !== Type::T_LIST) {
-            $this->throwError('expecting list');
-        }
-
-        return $value;
-    }
-
-    /**
-     * Assert value is a color
-     *
-     * @api
-     *
-     * @param array $value
-     *
-     * @return array
-     *
-     * @throws \Exception
-     */
-    public function assertColor($value)
-    {
-        if ($color = $this->coerceColor($value)) {
-            return $color;
-        }
-
-        $this->throwError('expecting color');
-    }
-
-    /**
-     * Assert value is a number
-     *
-     * @api
-     *
-     * @param array $value
-     *
-     * @return integer|float
-     *
-     * @throws \Exception
-     */
-    public function assertNumber($value)
-    {
-        if ($value[0] !== Type::T_NUMBER) {
-            $this->throwError('expecting number');
-        }
-
-        return $value[1];
-    }
-
-    /**
-     * Make sure a color's components don't go out of bounds
-     *
-     * @param array $c
-     *
-     * @return array
-     */
-    protected function fixColor($c)
-    {
-        foreach ([1, 2, 3] as $i) {
-            if ($c[$i] < 0) {
-                $c[$i] = 0;
-            }
-
-            if ($c[$i] > 255) {
-                $c[$i] = 255;
-            }
-        }
-
-        return $c;
-    }
-
-    /**
-     * Convert RGB to HSL
-     *
-     * @api
-     *
-     * @param integer $red
-     * @param integer $green
-     * @param integer $blue
-     *
-     * @return array
-     */
-    public function toHSL($red, $green, $blue)
-    {
-        $min = min($red, $green, $blue);
-        $max = max($red, $green, $blue);
-
-        $l = $min + $max;
-        $d = $max - $min;
-
-        if ((int) $d === 0) {
-            $h = $s = 0;
-        } else {
-            if ($l < 255) {
-                $s = $d / $l;
-            } else {
-                $s = $d / (510 - $l);
-            }
-
-            if ($red == $max) {
-                $h = 60 * ($green - $blue) / $d;
-            } elseif ($green == $max) {
-                $h = 60 * ($blue - $red) / $d + 120;
-            } elseif ($blue == $max) {
-                $h = 60 * ($red - $green) / $d + 240;
-            }
-        }
-
-        return [Type::T_HSL, fmod($h, 360), $s * 100, $l / 5.1];
-    }
-
-    /**
-     * Hue to RGB helper
-     *
-     * @param float $m1
-     * @param float $m2
-     * @param float $h
-     *
-     * @return float
-     */
-    private function hueToRGB($m1, $m2, $h)
-    {
-        if ($h < 0) {
-            $h += 1;
-        } elseif ($h > 1) {
-            $h -= 1;
-        }
-
-        if ($h * 6 < 1) {
-            return $m1 + ($m2 - $m1) * $h * 6;
-        }
-
-        if ($h * 2 < 1) {
-            return $m2;
-        }
-
-        if ($h * 3 < 2) {
-            return $m1 + ($m2 - $m1) * (2/3 - $h) * 6;
-        }
-
-        return $m1;
-    }
-
-    /**
-     * Convert HSL to RGB
-     *
-     * @api
-     *
-     * @param integer $hue        H from 0 to 360
-     * @param integer $saturation S from 0 to 100
-     * @param integer $lightness  L from 0 to 100
-     *
-     * @return array
-     */
-    public function toRGB($hue, $saturation, $lightness)
-    {
-        if ($hue < 0) {
-            $hue += 360;
-        }
-
-        $h = $hue / 360;
-        $s = min(100, max(0, $saturation)) / 100;
-        $l = min(100, max(0, $lightness)) / 100;
-
-        $m2 = $l <= 0.5 ? $l * ($s + 1) : $l + $s - $l * $s;
-        $m1 = $l * 2 - $m2;
-
-        $r = $this->hueToRGB($m1, $m2, $h + 1/3) * 255;
-        $g = $this->hueToRGB($m1, $m2, $h) * 255;
-        $b = $this->hueToRGB($m1, $m2, $h - 1/3) * 255;
-
-        $out = [Type::T_COLOR, $r, $g, $b];
-
-        return $out;
-    }
-
-    // Built in functions
-
-    //protected static $libCall = ['name', 'args...'];
-    protected function libCall($args, $kwargs)
-    {
-        $name = $this->compileStringContent($this->coerceString($this->reduce(array_shift($args), true)));
-
-        $args = array_map(
-            function ($a) {
-                return [null, $a, false];
-            },
-            $args
-        );
-
-        if (count($kwargs)) {
-            foreach ($kwargs as $key => $value) {
-                $args[] = [[Type::T_VARIABLE, $key], $value, false];
-            }
-        }
-
-        return $this->reduce([Type::T_FUNCTION_CALL, $name, $args]);
-    }
-
-    protected static $libIf = ['condition', 'if-true', 'if-false'];
-    protected function libIf($args)
-    {
-        list($cond, $t, $f) = $args;
-
-        if (! $this->isTruthy($this->reduce($cond, true))) {
-            return $this->reduce($f, true);
-        }
-
-        return $this->reduce($t, true);
-    }
-
-    protected static $libIndex = ['list', 'value'];
-    protected function libIndex($args)
-    {
-        list($list, $value) = $args;
-
-        if ($value[0] === Type::T_MAP) {
-            return static::$null;
-        }
-
-        if ($list[0] === Type::T_MAP ||
-            $list[0] === Type::T_STRING ||
-            $list[0] === Type::T_KEYWORD ||
-            $list[0] === Type::T_INTERPOLATE
-        ) {
-            $list = $this->coerceList($list, ' ');
-        }
-
-        if ($list[0] !== Type::T_LIST) {
-            return static::$null;
-        }
-
-        $values = [];
-
-        foreach ($list[2] as $item) {
-            $values[] = $this->normalizeValue($item);
-        }
-
-        $key = array_search($this->normalizeValue($value), $values);
-
-        return false === $key ? static::$null : $key + 1;
-    }
-
-    protected static $libRgb = ['red', 'green', 'blue'];
-    protected function libRgb($args)
-    {
-        list($r, $g, $b) = $args;
-
-        return [Type::T_COLOR, $r[1], $g[1], $b[1]];
-    }
-
-    protected static $libRgba = [
-        ['red', 'color'],
-        'green', 'blue', 'alpha'];
-    protected function libRgba($args)
-    {
-        if ($color = $this->coerceColor($args[0])) {
-            $num = ! isset($args[1]) ? $args[3] : $args[1];
-            $alpha = $this->assertNumber($num);
-            $color[4] = $alpha;
-
-            return $color;
-        }
-
-        list($r, $g, $b, $a) = $args;
-
-        return [Type::T_COLOR, $r[1], $g[1], $b[1], $a[1]];
-    }
-
-    // helper function for adjust_color, change_color, and scale_color
-    protected function alterColor($args, $fn)
-    {
-        $color = $this->assertColor($args[0]);
-
-        foreach ([1, 2, 3, 7] as $i) {
-            if (isset($args[$i])) {
-                $val = $this->assertNumber($args[$i]);
-                $ii = $i === 7 ? 4 : $i; // alpha
-                $color[$ii] = call_user_func($fn, isset($color[$ii]) ? $color[$ii] : 0, $val, $i);
-            }
-        }
-
-        if (isset($args[4]) || isset($args[5]) || isset($args[6])) {
-            $hsl = $this->toHSL($color[1], $color[2], $color[3]);
-
-            foreach ([4, 5, 6] as $i) {
-                if (isset($args[$i])) {
-                    $val = $this->assertNumber($args[$i]);
-                    $hsl[$i - 3] = call_user_func($fn, $hsl[$i - 3], $val, $i);
-                }
-            }
-
-            $rgb = $this->toRGB($hsl[1], $hsl[2], $hsl[3]);
-
-            if (isset($color[4])) {
-                $rgb[4] = $color[4];
-            }
-
-            $color = $rgb;
-        }
-
-        return $color;
-    }
-
-    protected static $libAdjustColor = [
-        'color', 'red', 'green', 'blue',
-        'hue', 'saturation', 'lightness', 'alpha'
-    ];
-    protected function libAdjustColor($args)
-    {
-        return $this->alterColor($args, function ($base, $alter, $i) {
-            return $base + $alter;
-        });
-    }
-
-    protected static $libChangeColor = [
-        'color', 'red', 'green', 'blue',
-        'hue', 'saturation', 'lightness', 'alpha'
-    ];
-    protected function libChangeColor($args)
-    {
-        return $this->alterColor($args, function ($base, $alter, $i) {
-            return $alter;
-        });
-    }
-
-    protected static $libScaleColor = [
-        'color', 'red', 'green', 'blue',
-        'hue', 'saturation', 'lightness', 'alpha'
-    ];
-    protected function libScaleColor($args)
-    {
-        return $this->alterColor($args, function ($base, $scale, $i) {
-            // 1, 2, 3 - rgb
-            // 4, 5, 6 - hsl
-            // 7 - a
-            switch ($i) {
-                case 1:
-                case 2:
-                case 3:
-                    $max = 255;
-                    break;
-
-                case 4:
-                    $max = 360;
-                    break;
-
-                case 7:
-                    $max = 1;
-                    break;
-
-                default:
-                    $max = 100;
-            }
-
-            $scale = $scale / 100;
-
-            if ($scale < 0) {
-                return $base * $scale + $base;
-            }
-
-            return ($max - $base) * $scale + $base;
-        });
-    }
-
-    protected static $libIeHexStr = ['color'];
-    protected function libIeHexStr($args)
-    {
-        $color = $this->coerceColor($args[0]);
-        $color[4] = isset($color[4]) ? round(255 * $color[4]) : 255;
-
-        return sprintf('#%02X%02X%02X%02X', $color[4], $color[1], $color[2], $color[3]);
-    }
-
-    protected static $libRed = ['color'];
-    protected function libRed($args)
-    {
-        $color = $this->coerceColor($args[0]);
-
-        return $color[1];
-    }
-
-    protected static $libGreen = ['color'];
-    protected function libGreen($args)
-    {
-        $color = $this->coerceColor($args[0]);
-
-        return $color[2];
-    }
-
-    protected static $libBlue = ['color'];
-    protected function libBlue($args)
-    {
-        $color = $this->coerceColor($args[0]);
-
-        return $color[3];
-    }
-
-    protected static $libAlpha = ['color'];
-    protected function libAlpha($args)
-    {
-        if ($color = $this->coerceColor($args[0])) {
-            return isset($color[4]) ? $color[4] : 1;
-        }
-
-        // this might be the IE function, so return value unchanged
-        return null;
-    }
-
-    protected static $libOpacity = ['color'];
-    protected function libOpacity($args)
-    {
-        $value = $args[0];
-
-        if ($value[0] === Type::T_NUMBER) {
-            return null;
-        }
-
-        return $this->libAlpha($args);
-    }
-
-    // mix two colors
-    protected static $libMix = ['color-1', 'color-2', 'weight'];
-    protected function libMix($args)
-    {
-        list($first, $second, $weight) = $args;
-
-        $first = $this->assertColor($first);
-        $second = $this->assertColor($second);
-
-        if (! isset($weight)) {
-            $weight = 0.5;
-        } else {
-            $weight = $this->coercePercent($weight);
-        }
-
-        $firstAlpha = isset($first[4]) ? $first[4] : 1;
-        $secondAlpha = isset($second[4]) ? $second[4] : 1;
-
-        $w = $weight * 2 - 1;
-        $a = $firstAlpha - $secondAlpha;
-
-        $w1 = (($w * $a === -1 ? $w : ($w + $a) / (1 + $w * $a)) + 1) / 2.0;
-        $w2 = 1.0 - $w1;
-
-        $new = [Type::T_COLOR,
-            $w1 * $first[1] + $w2 * $second[1],
-            $w1 * $first[2] + $w2 * $second[2],
-            $w1 * $first[3] + $w2 * $second[3],
-        ];
-
-        if ($firstAlpha != 1.0 || $secondAlpha != 1.0) {
-            $new[] = $firstAlpha * $weight + $secondAlpha * ($weight - 1);
-        }
-
-        return $this->fixColor($new);
-    }
-
-    protected static $libHsl = ['hue', 'saturation', 'lightness'];
-    protected function libHsl($args)
-    {
-        list($h, $s, $l) = $args;
-
-        return $this->toRGB($h[1], $s[1], $l[1]);
-    }
-
-    protected static $libHsla = ['hue', 'saturation', 'lightness', 'alpha'];
-    protected function libHsla($args)
-    {
-        list($h, $s, $l, $a) = $args;
-
-        $color = $this->toRGB($h[1], $s[1], $l[1]);
-        $color[4] = $a[1];
-
-        return $color;
-    }
-
-    protected static $libHue = ['color'];
-    protected function libHue($args)
-    {
-        $color = $this->assertColor($args[0]);
-        $hsl = $this->toHSL($color[1], $color[2], $color[3]);
-
-        return new Node\Number($hsl[1], 'deg');
-    }
-
-    protected static $libSaturation = ['color'];
-    protected function libSaturation($args)
-    {
-        $color = $this->assertColor($args[0]);
-        $hsl = $this->toHSL($color[1], $color[2], $color[3]);
-
-        return new Node\Number($hsl[2], '%');
-    }
-
-    protected static $libLightness = ['color'];
-    protected function libLightness($args)
-    {
-        $color = $this->assertColor($args[0]);
-        $hsl = $this->toHSL($color[1], $color[2], $color[3]);
-
-        return new Node\Number($hsl[3], '%');
-    }
-
-    protected function adjustHsl($color, $idx, $amount)
-    {
-        $hsl = $this->toHSL($color[1], $color[2], $color[3]);
-        $hsl[$idx] += $amount;
-        $out = $this->toRGB($hsl[1], $hsl[2], $hsl[3]);
-
-        if (isset($color[4])) {
-            $out[4] = $color[4];
-        }
-
-        return $out;
-    }
-
-    protected static $libAdjustHue = ['color', 'degrees'];
-    protected function libAdjustHue($args)
-    {
-        $color = $this->assertColor($args[0]);
-        $degrees = $this->assertNumber($args[1]);
-
-        return $this->adjustHsl($color, 1, $degrees);
-    }
-
-    protected static $libLighten = ['color', 'amount'];
-    protected function libLighten($args)
-    {
-        $color = $this->assertColor($args[0]);
-        $amount = Util::checkRange('amount', new Range(0, 100), $args[1], '%');
-
-        return $this->adjustHsl($color, 3, $amount);
-    }
-
-    protected static $libDarken = ['color', 'amount'];
-    protected function libDarken($args)
-    {
-        $color = $this->assertColor($args[0]);
-        $amount = Util::checkRange('amount', new Range(0, 100), $args[1], '%');
-
-        return $this->adjustHsl($color, 3, -$amount);
-    }
-
-    protected static $libSaturate = ['color', 'amount'];
-    protected function libSaturate($args)
-    {
-        $value = $args[0];
-
-        if ($value[0] === Type::T_NUMBER) {
-            return null;
-        }
-
-        $color = $this->assertColor($value);
-        $amount = 100 * $this->coercePercent($args[1]);
-
-        return $this->adjustHsl($color, 2, $amount);
-    }
-
-    protected static $libDesaturate = ['color', 'amount'];
-    protected function libDesaturate($args)
-    {
-        $color = $this->assertColor($args[0]);
-        $amount = 100 * $this->coercePercent($args[1]);
-
-        return $this->adjustHsl($color, 2, -$amount);
-    }
-
-    protected static $libGrayscale = ['color'];
-    protected function libGrayscale($args)
-    {
-        $value = $args[0];
-
-        if ($value[0] === Type::T_NUMBER) {
-            return null;
-        }
-
-        return $this->adjustHsl($this->assertColor($value), 2, -100);
-    }
-
-    protected static $libComplement = ['color'];
-    protected function libComplement($args)
-    {
-        return $this->adjustHsl($this->assertColor($args[0]), 1, 180);
-    }
-
-    protected static $libInvert = ['color'];
-    protected function libInvert($args)
-    {
-        $value = $args[0];
-
-        if ($value[0] === Type::T_NUMBER) {
-            return null;
-        }
-
-        $color = $this->assertColor($value);
-        $color[1] = 255 - $color[1];
-        $color[2] = 255 - $color[2];
-        $color[3] = 255 - $color[3];
-
-        return $color;
-    }
-
-    // increases opacity by amount
-    protected static $libOpacify = ['color', 'amount'];
-    protected function libOpacify($args)
-    {
-        $color = $this->assertColor($args[0]);
-        $amount = $this->coercePercent($args[1]);
-
-        $color[4] = (isset($color[4]) ? $color[4] : 1) + $amount;
-        $color[4] = min(1, max(0, $color[4]));
-
-        return $color;
-    }
-
-    protected static $libFadeIn = ['color', 'amount'];
-    protected function libFadeIn($args)
-    {
-        return $this->libOpacify($args);
-    }
-
-    // decreases opacity by amount
-    protected static $libTransparentize = ['color', 'amount'];
-    protected function libTransparentize($args)
-    {
-        $color = $this->assertColor($args[0]);
-        $amount = $this->coercePercent($args[1]);
-
-        $color[4] = (isset($color[4]) ? $color[4] : 1) - $amount;
-        $color[4] = min(1, max(0, $color[4]));
-
-        return $color;
-    }
-
-    protected static $libFadeOut = ['color', 'amount'];
-    protected function libFadeOut($args)
-    {
-        return $this->libTransparentize($args);
-    }
-
-    protected static $libUnquote = ['string'];
-    protected function libUnquote($args)
-    {
-        $str = $args[0];
-
-        if ($str[0] === Type::T_STRING) {
-            $str[1] = '';
-        }
-
-        return $str;
-    }
-
-    protected static $libQuote = ['string'];
-    protected function libQuote($args)
-    {
-        $value = $args[0];
-
-        if ($value[0] === Type::T_STRING && ! empty($value[1])) {
-            return $value;
-        }
-
-        return [Type::T_STRING, '"', [$value]];
-    }
-
-    protected static $libPercentage = ['value'];
-    protected function libPercentage($args)
-    {
-        return new Node\Number($this->coercePercent($args[0]) * 100, '%');
-    }
-
-    protected static $libRound = ['value'];
-    protected function libRound($args)
-    {
-        $num = $args[0];
-
-        return new Node\Number(round($num[1]), $num[2]);
-    }
-
-    protected static $libFloor = ['value'];
-    protected function libFloor($args)
-    {
-        $num = $args[0];
-
-        return new Node\Number(floor($num[1]), $num[2]);
-    }
-
-    protected static $libCeil = ['value'];
-    protected function libCeil($args)
-    {
-        $num = $args[0];
-
-        return new Node\Number(ceil($num[1]), $num[2]);
-    }
-
-    protected static $libAbs = ['value'];
-    protected function libAbs($args)
-    {
-        $num = $args[0];
-
-        return new Node\Number(abs($num[1]), $num[2]);
-    }
-
-    protected function libMin($args)
-    {
-        $numbers = $this->getNormalizedNumbers($args);
-        $min = null;
-
-        foreach ($numbers as $key => $number) {
-            if (null === $min || $number[1] <= $min[1]) {
-                $min = [$key, $number[1]];
-            }
-        }
-
-        return $args[$min[0]];
-    }
-
-    protected function libMax($args)
-    {
-        $numbers = $this->getNormalizedNumbers($args);
-        $max = null;
-
-        foreach ($numbers as $key => $number) {
-            if (null === $max || $number[1] >= $max[1]) {
-                $max = [$key, $number[1]];
-            }
-        }
-
-        return $args[$max[0]];
-    }
-
-    /**
-     * Helper to normalize args containing numbers
-     *
-     * @param array $args
-     *
-     * @return array
-     */
-    protected function getNormalizedNumbers($args)
-    {
-        $unit = null;
-        $originalUnit = null;
-        $numbers = [];
-
-        foreach ($args as $key => $item) {
-            if ($item[0] !== Type::T_NUMBER) {
-                $this->throwError('%s is not a number', $item[0]);
-                break;
-            }
-
-            $number = $item->normalize();
-
-            if (null === $unit) {
-                $unit = $number[2];
-                $originalUnit = $item->unitStr();
-            } elseif ($unit !== $number[2]) {
-                $this->throwError('Incompatible units: "%s" and "%s".', $originalUnit, $item->unitStr());
-                break;
-            }
-
-            $numbers[$key] = $number;
-        }
-
-        return $numbers;
-    }
-
-    protected static $libLength = ['list'];
-    protected function libLength($args)
-    {
-        $list = $this->coerceList($args[0]);
-
-        return count($list[2]);
-    }
-
-    //protected static $libListSeparator = ['list...'];
-    protected function libListSeparator($args)
-    {
-        if (count($args) > 1) {
-            return 'comma';
-        }
-
-        $list = $this->coerceList($args[0]);
-
-        if (count($list[2]) <= 1) {
-            return 'space';
-        }
-
-        if ($list[1] === ',') {
-            return 'comma';
-        }
-
-        return 'space';
-    }
-
-    protected static $libNth = ['list', 'n'];
-    protected function libNth($args)
-    {
-        $list = $this->coerceList($args[0]);
-        $n = $this->assertNumber($args[1]);
-
-        if ($n > 0) {
-            $n--;
-        } elseif ($n < 0) {
-            $n += count($list[2]);
-        }
-
-        return isset($list[2][$n]) ? $list[2][$n] : static::$defaultValue;
-    }
-
-    protected static $libSetNth = ['list', 'n', 'value'];
-    protected function libSetNth($args)
-    {
-        $list = $this->coerceList($args[0]);
-        $n = $this->assertNumber($args[1]);
-
-        if ($n > 0) {
-            $n--;
-        } elseif ($n < 0) {
-            $n += count($list[2]);
-        }
-
-        if (! isset($list[2][$n])) {
-            $this->throwError('Invalid argument for "n"');
-
-            return;
-        }
-
-        $list[2][$n] = $args[2];
-
-        return $list;
-    }
-
-    protected static $libMapGet = ['map', 'key'];
-    protected function libMapGet($args)
-    {
-        $map = $this->assertMap($args[0]);
-        $key = $this->compileStringContent($this->coerceString($args[1]));
-
-        for ($i = count($map[1]) - 1; $i >= 0; $i--) {
-            if ($key === $this->compileStringContent($this->coerceString($map[1][$i]))) {
-                return $map[2][$i];
-            }
-        }
-
-        return static::$null;
-    }
-
-    protected static $libMapKeys = ['map'];
-    protected function libMapKeys($args)
-    {
-        $map = $this->assertMap($args[0]);
-        $keys = $map[1];
-
-        return [Type::T_LIST, ',', $keys];
-    }
-
-    protected static $libMapValues = ['map'];
-    protected function libMapValues($args)
-    {
-        $map = $this->assertMap($args[0]);
-        $values = $map[2];
-
-        return [Type::T_LIST, ',', $values];
-    }
-
-    protected static $libMapRemove = ['map', 'key'];
-    protected function libMapRemove($args)
-    {
-        $map = $this->assertMap($args[0]);
-        $key = $this->compileStringContent($this->coerceString($args[1]));
-
-        for ($i = count($map[1]) - 1; $i >= 0; $i--) {
-            if ($key === $this->compileStringContent($this->coerceString($map[1][$i]))) {
-                array_splice($map[1], $i, 1);
-                array_splice($map[2], $i, 1);
-            }
-        }
-
-        return $map;
-    }
-
-    protected static $libMapHasKey = ['map', 'key'];
-    protected function libMapHasKey($args)
-    {
-        $map = $this->assertMap($args[0]);
-        $key = $this->compileStringContent($this->coerceString($args[1]));
-
-        for ($i = count($map[1]) - 1; $i >= 0; $i--) {
-            if ($key === $this->compileStringContent($this->coerceString($map[1][$i]))) {
-                return true;
-            }
-        }
-
-        return false;
-    }
-
-    protected static $libMapMerge = ['map-1', 'map-2'];
-    protected function libMapMerge($args)
-    {
-        $map1 = $this->assertMap($args[0]);
-        $map2 = $this->assertMap($args[1]);
-
-        return [Type::T_MAP, array_merge($map1[1], $map2[1]), array_merge($map1[2], $map2[2])];
-    }
-
-    protected static $libKeywords = ['args'];
-    protected function libKeywords($args)
-    {
-        $this->assertList($args[0]);
-
-        $keys = [];
-        $values = [];
-
-        foreach ($args[0][2] as $name => $arg) {
-            $keys[] = [Type::T_KEYWORD, $name];
-            $values[] = $arg;
-        }
-
-        return [Type::T_MAP, $keys, $values];
-    }
-
-    protected function listSeparatorForJoin($list1, $sep)
-    {
-        if (! isset($sep)) {
-            return $list1[1];
-        }
-
-        switch ($this->compileValue($sep)) {
-            case 'comma':
-                return ',';
-
-            case 'space':
-                return '';
-
-            default:
-                return $list1[1];
-        }
-    }
-
-    protected static $libJoin = ['list1', 'list2', 'separator'];
-    protected function libJoin($args)
-    {
-        list($list1, $list2, $sep) = $args;
-
-        $list1 = $this->coerceList($list1, ' ');
-        $list2 = $this->coerceList($list2, ' ');
-        $sep = $this->listSeparatorForJoin($list1, $sep);
-
-        return [Type::T_LIST, $sep, array_merge($list1[2], $list2[2])];
-    }
-
-    protected static $libAppend = ['list', 'val', 'separator'];
-    protected function libAppend($args)
-    {
-        list($list1, $value, $sep) = $args;
-
-        $list1 = $this->coerceList($list1, ' ');
-        $sep = $this->listSeparatorForJoin($list1, $sep);
-
-        return [Type::T_LIST, $sep, array_merge($list1[2], [$value])];
-    }
-
-    protected function libZip($args)
-    {
-        foreach ($args as $arg) {
-            $this->assertList($arg);
-        }
-
-        $lists = [];
-        $firstList = array_shift($args);
-
-        foreach ($firstList[2] as $key => $item) {
-            $list = [Type::T_LIST, '', [$item]];
-
-            foreach ($args as $arg) {
-                if (isset($arg[2][$key])) {
-                    $list[2][] = $arg[2][$key];
-                } else {
-                    break 2;
-                }
-            }
-
-            $lists[] = $list;
-        }
-
-        return [Type::T_LIST, ',', $lists];
-    }
-
-    protected static $libTypeOf = ['value'];
-    protected function libTypeOf($args)
-    {
-        $value = $args[0];
-
-        switch ($value[0]) {
-            case Type::T_KEYWORD:
-                if ($value === static::$true || $value === static::$false) {
-                    return 'bool';
-                }
-
-                if ($this->coerceColor($value)) {
-                    return 'color';
-                }
-
-                // fall-thru
-            case Type::T_FUNCTION:
-                return 'string';
-
-            case Type::T_LIST:
-                if (isset($value[3]) && $value[3]) {
-                    return 'arglist';
-                }
-
-                // fall-thru
-            default:
-                return $value[0];
-        }
-    }
-
-    protected static $libUnit = ['number'];
-    protected function libUnit($args)
-    {
-        $num = $args[0];
-
-        if ($num[0] === Type::T_NUMBER) {
-            return [Type::T_STRING, '"', [$num->unitStr()]];
-        }
-
-        return '';
-    }
-
-    protected static $libUnitless = ['number'];
-    protected function libUnitless($args)
-    {
-        $value = $args[0];
-
-        return $value[0] === Type::T_NUMBER && $value->unitless();
-    }
-
-    protected static $libComparable = ['number-1', 'number-2'];
-    protected function libComparable($args)
-    {
-        list($number1, $number2) = $args;
-
-        if (! isset($number1[0]) || $number1[0] !== Type::T_NUMBER ||
-            ! isset($number2[0]) || $number2[0] !== Type::T_NUMBER
-        ) {
-            $this->throwError('Invalid argument(s) for "comparable"');
-
-            return;
-        }
-
-        $number1 = $number1->normalize();
-        $number2 = $number2->normalize();
-
-        return $number1[2] === $number2[2] || $number1->unitless() || $number2->unitless();
-    }
-
-    protected static $libStrIndex = ['string', 'substring'];
-    protected function libStrIndex($args)
-    {
-        $string = $this->coerceString($args[0]);
-        $stringContent = $this->compileStringContent($string);
-
-        $substring = $this->coerceString($args[1]);
-        $substringContent = $this->compileStringContent($substring);
-
-        $result = strpos($stringContent, $substringContent);
-
-        return $result === false ? static::$null : new Node\Number($result + 1, '');
-    }
-
-    protected static $libStrInsert = ['string', 'insert', 'index'];
-    protected function libStrInsert($args)
-    {
-        $string = $this->coerceString($args[0]);
-        $stringContent = $this->compileStringContent($string);
-
-        $insert = $this->coerceString($args[1]);
-        $insertContent = $this->compileStringContent($insert);
-
-        list(, $index) = $args[2];
-
-        $string[2] = [substr_replace($stringContent, $insertContent, $index - 1, 0)];
-
-        return $string;
-    }
-
-    protected static $libStrLength = ['string'];
-    protected function libStrLength($args)
-    {
-        $string = $this->coerceString($args[0]);
-        $stringContent = $this->compileStringContent($string);
-
-        return new Node\Number(strlen($stringContent), '');
-    }
-
-    protected static $libStrSlice = ['string', 'start-at', 'end-at'];
-    protected function libStrSlice($args)
-    {
-        if (isset($args[2]) && $args[2][1] == 0) {
-            return static::$nullString;
-        }
-
-        $string = $this->coerceString($args[0]);
-        $stringContent = $this->compileStringContent($string);
-
-        $start = (int) $args[1][1];
-
-        if ($start > 0) {
-            $start--;
-        }
-
-        $end    = (int) $args[2][1];
-        $length = $end < 0 ? $end + 1 : ($end > 0 ? $end - $start : $end);
-
-        $string[2] = $length
-            ? [substr($stringContent, $start, $length)]
-            : [substr($stringContent, $start)];
-
-        return $string;
-    }
-
-    protected static $libToLowerCase = ['string'];
-    protected function libToLowerCase($args)
-    {
-        $string = $this->coerceString($args[0]);
-        $stringContent = $this->compileStringContent($string);
-
-        $string[2] = [function_exists('mb_strtolower') ? mb_strtolower($stringContent) : strtolower($stringContent)];
-
-        return $string;
-    }
-
-    protected static $libToUpperCase = ['string'];
-    protected function libToUpperCase($args)
-    {
-        $string = $this->coerceString($args[0]);
-        $stringContent = $this->compileStringContent($string);
-
-        $string[2] = [function_exists('mb_strtoupper') ? mb_strtoupper($stringContent) : strtoupper($stringContent)];
-
-        return $string;
-    }
-
-    protected static $libFeatureExists = ['feature'];
-    protected function libFeatureExists($args)
-    {
-        $string = $this->coerceString($args[0]);
-        $name = $this->compileStringContent($string);
-
-        return $this->toBool(
-            array_key_exists($name, $this->registeredFeatures) ? $this->registeredFeatures[$name] : false
-        );
-    }
-
-    protected static $libFunctionExists = ['name'];
-    protected function libFunctionExists($args)
-    {
-        $string = $this->coerceString($args[0]);
-        $name = $this->compileStringContent($string);
-
-        // user defined functions
-        if ($this->has(static::$namespaces['function'] . $name)) {
-            return true;
-        }
-
-        $name = $this->normalizeName($name);
-
-        if (isset($this->userFunctions[$name])) {
-            return true;
-        }
-
-        // built-in functions
-        $f = $this->getBuiltinFunction($name);
-
-        return $this->toBool(is_callable($f));
-    }
-
-    protected static $libGlobalVariableExists = ['name'];
-    protected function libGlobalVariableExists($args)
-    {
-        $string = $this->coerceString($args[0]);
-        $name = $this->compileStringContent($string);
-
-        return $this->has($name, $this->rootEnv);
-    }
-
-    protected static $libMixinExists = ['name'];
-    protected function libMixinExists($args)
-    {
-        $string = $this->coerceString($args[0]);
-        $name = $this->compileStringContent($string);
-
-        return $this->has(static::$namespaces['mixin'] . $name);
-    }
-
-    protected static $libVariableExists = ['name'];
-    protected function libVariableExists($args)
-    {
-        $string = $this->coerceString($args[0]);
-        $name = $this->compileStringContent($string);
-
-        return $this->has($name);
-    }
-
-    /**
-     * Workaround IE7's content counter bug.
-     *
-     * @param array $args
-     *
-     * @return array
-     */
-    protected function libCounter($args)
-    {
-        $list = array_map([$this, 'compileValue'], $args);
-
-        return [Type::T_STRING, '', ['counter(' . implode(',', $list) . ')']];
-    }
-
-    protected static $libRandom = ['limit'];
-    protected function libRandom($args)
-    {
-        if (isset($args[0])) {
-            $n = $this->assertNumber($args[0]);
-
-            if ($n < 1) {
-                $this->throwError("limit must be greater than or equal to 1");
-
-                return;
-            }
-
-            return new Node\Number(mt_rand(1, $n), '');
-        }
-
-        return new Node\Number(mt_rand(1, mt_getrandmax()), '');
-    }
-
-    protected function libUniqueId()
-    {
-        static $id;
-
-        if (! isset($id)) {
-            $id = mt_rand(0, pow(36, 8));
-        }
-
-        $id += mt_rand(0, 10) + 1;
-
-        return [Type::T_STRING, '', ['u' . str_pad(base_convert($id, 10, 36), 8, '0', STR_PAD_LEFT)]];
-    }
-
-    protected static $libInspect = ['value'];
-    protected function libInspect($args)
-    {
-        if ($args[0] === static::$null) {
-            return [Type::T_KEYWORD, 'null'];
-        }
-
-        return $args[0];
-    }
-}
diff --git a/inc/scssphp--old/src/Compiler/Environment.php b/inc/scssphp--old/src/Compiler/Environment.php
deleted file mode 100644
index fe309dd..0000000
--- a/inc/scssphp--old/src/Compiler/Environment.php
+++ /dev/null
@@ -1,40 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp\Compiler;
-
-/**
- * Compiler environment
- *
- * @author Anthon Pang <anthon.pang@gmail.com>
- */
-class Environment
-{
-    /**
-     * @var \Leafo\ScssPhp\Block
-     */
-    public $block;
-
-    /**
-     * @var \Leafo\ScssPhp\Compiler\Environment
-     */
-    public $parent;
-
-    /**
-     * @var array
-     */
-    public $store;
-
-    /**
-     * @var integer
-     */
-    public $depth;
-}
diff --git a/inc/scssphp--old/src/Exception/CompilerException.php b/inc/scssphp--old/src/Exception/CompilerException.php
deleted file mode 100644
index 7ca2e2b..0000000
--- a/inc/scssphp--old/src/Exception/CompilerException.php
+++ /dev/null
@@ -1,21 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp\Exception;
-
-/**
- * Compiler exception
- *
- * @author Oleksandr Savchenko <traveltino@gmail.com>
- */
-class CompilerException extends \Exception
-{
-}
diff --git a/inc/scssphp--old/src/Exception/ParserException.php b/inc/scssphp--old/src/Exception/ParserException.php
deleted file mode 100644
index 6d64335..0000000
--- a/inc/scssphp--old/src/Exception/ParserException.php
+++ /dev/null
@@ -1,21 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp\Exception;
-
-/**
- * Parser Exception
- *
- * @author Oleksandr Savchenko <traveltino@gmail.com>
- */
-class ParserException extends \Exception
-{
-}
diff --git a/inc/scssphp--old/src/Exception/RangeException.php b/inc/scssphp--old/src/Exception/RangeException.php
deleted file mode 100644
index 3ba6bf1..0000000
--- a/inc/scssphp--old/src/Exception/RangeException.php
+++ /dev/null
@@ -1,21 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp\Exception;
-
-/**
- * Range exception
- *
- * @author Anthon Pang <anthon.pang@gmail.com>
- */
-class RangeException extends \Exception
-{
-}
diff --git a/inc/scssphp--old/src/Exception/ServerException.php b/inc/scssphp--old/src/Exception/ServerException.php
deleted file mode 100644
index d0ed084..0000000
--- a/inc/scssphp--old/src/Exception/ServerException.php
+++ /dev/null
@@ -1,21 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp\Exception;
-
-/**
- * Server Exception
- *
- * @author Anthon Pang <anthon.pang@gmail.com>
- */
-class ServerException extends \Exception
-{
-}
diff --git a/inc/scssphp--old/src/Formatter.php b/inc/scssphp--old/src/Formatter.php
deleted file mode 100644
index b4f90aa..0000000
--- a/inc/scssphp--old/src/Formatter.php
+++ /dev/null
@@ -1,274 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp;
-
-use Leafo\ScssPhp\Formatter\OutputBlock;
-use Leafo\ScssPhp\SourceMap\SourceMapGenerator;
-
-/**
- * Base formatter
- *
- * @author Leaf Corcoran <leafot@gmail.com>
- */
-abstract class Formatter
-{
-    /**
-     * @var integer
-     */
-    public $indentLevel;
-
-    /**
-     * @var string
-     */
-    public $indentChar;
-
-    /**
-     * @var string
-     */
-    public $break;
-
-    /**
-     * @var string
-     */
-    public $open;
-
-    /**
-     * @var string
-     */
-    public $close;
-
-    /**
-     * @var string
-     */
-    public $tagSeparator;
-
-    /**
-     * @var string
-     */
-    public $assignSeparator;
-
-    /**
-     * @var boolean
-     */
-    public $keepSemicolons;
-
-    /**
-     * @var \Leafo\ScssPhp\Formatter\OutputBlock
-     */
-    protected $currentBlock;
-
-    /**
-     * @var integer
-     */
-    protected $currentLine;
-
-    /**
-     * @var integer
-     */
-    protected $currentColumn;
-
-    /**
-     * @var \Leafo\ScssPhp\SourceMap\SourceMapGenerator
-     */
-    protected $sourceMapGenerator;
-
-    /**
-     * Initialize formatter
-     *
-     * @api
-     */
-    abstract public function __construct();
-
-    /**
-     * Return indentation (whitespace)
-     *
-     * @return string
-     */
-    protected function indentStr()
-    {
-        return '';
-    }
-
-    /**
-     * Return property assignment
-     *
-     * @api
-     *
-     * @param string $name
-     * @param mixed  $value
-     *
-     * @return string
-     */
-    public function property($name, $value)
-    {
-        return rtrim($name) . $this->assignSeparator . $value . ';';
-    }
-
-    /**
-     * Strip semi-colon appended by property(); it's a separator, not a terminator
-     *
-     * @api
-     *
-     * @param array $lines
-     */
-    public function stripSemicolon(&$lines)
-    {
-        if ($this->keepSemicolons) {
-            return;
-        }
-
-        if (($count = count($lines))
-            && substr($lines[$count - 1], -1) === ';'
-        ) {
-            $lines[$count - 1] = substr($lines[$count - 1], 0, -1);
-        }
-    }
-
-    /**
-     * Output lines inside a block
-     *
-     * @param \Leafo\ScssPhp\Formatter\OutputBlock $block
-     */
-    protected function blockLines(OutputBlock $block)
-    {
-        $inner = $this->indentStr();
-
-        $glue = $this->break . $inner;
-
-        $this->write($inner . implode($glue, $block->lines));
-
-        if (! empty($block->children)) {
-            $this->write($this->break);
-        }
-    }
-
-    /**
-     * Output block selectors
-     *
-     * @param \Leafo\ScssPhp\Formatter\OutputBlock $block
-     */
-    protected function blockSelectors(OutputBlock $block)
-    {
-        $inner = $this->indentStr();
-
-        $this->write($inner
-            . implode($this->tagSeparator, $block->selectors)
-            . $this->open . $this->break);
-    }
-
-    /**
-     * Output block children
-     *
-     * @param \Leafo\ScssPhp\Formatter\OutputBlock $block
-     */
-    protected function blockChildren(OutputBlock $block)
-    {
-        foreach ($block->children as $child) {
-            $this->block($child);
-        }
-    }
-
-    /**
-     * Output non-empty block
-     *
-     * @param \Leafo\ScssPhp\Formatter\OutputBlock $block
-     */
-    protected function block(OutputBlock $block)
-    {
-        if (empty($block->lines) && empty($block->children)) {
-            return;
-        }
-
-        $this->currentBlock = $block;
-
-        $pre = $this->indentStr();
-
-        if (! empty($block->selectors)) {
-            $this->blockSelectors($block);
-
-            $this->indentLevel++;
-        }
-
-        if (! empty($block->lines)) {
-            $this->blockLines($block);
-        }
-
-        if (! empty($block->children)) {
-            $this->blockChildren($block);
-        }
-
-        if (! empty($block->selectors)) {
-            $this->indentLevel--;
-
-            if (empty($block->children)) {
-                $this->write($this->break);
-            }
-
-            $this->write($pre . $this->close . $this->break);
-        }
-    }
-
-    /**
-     * Entry point to formatting a block
-     *
-     * @api
-     *
-     * @param \Leafo\ScssPhp\Formatter\OutputBlock             $block              An abstract syntax tree
-     * @param \Leafo\ScssPhp\SourceMap\SourceMapGenerator|null $sourceMapGenerator Optional source map generator
-     *
-     * @return string
-     */
-    public function format(OutputBlock $block, SourceMapGenerator $sourceMapGenerator = null)
-    {
-        $this->sourceMapGenerator = null;
-
-        if ($sourceMapGenerator) {
-            $this->currentLine = 1;
-            $this->currentColumn = 0;
-            $this->sourceMapGenerator = $sourceMapGenerator;
-        }
-
-        ob_start();
-
-        $this->block($block);
-
-        $out = ob_get_clean();
-
-        return $out;
-    }
-
-    /**
-     * @param string $str
-     */
-    protected function write($str)
-    {
-        if ($this->sourceMapGenerator) {
-            $this->sourceMapGenerator->addMapping(
-                $this->currentLine,
-                $this->currentColumn,
-                $this->currentBlock->sourceLine,
-                $this->currentBlock->sourceColumn - 1, //columns from parser are off by one
-                $this->currentBlock->sourceName
-            );
-
-            $lines = explode("\n", $str);
-            $lineCount = count($lines);
-            $this->currentLine += $lineCount-1;
-
-            $lastLine = array_pop($lines);
-
-            $this->currentColumn = ($lineCount === 1 ? $this->currentColumn : 0) + strlen($lastLine);
-        }
-
-        echo $str;
-    }
-}
diff --git a/inc/scssphp--old/src/Formatter/Compact.php b/inc/scssphp--old/src/Formatter/Compact.php
deleted file mode 100644
index 4efa1a0..0000000
--- a/inc/scssphp--old/src/Formatter/Compact.php
+++ /dev/null
@@ -1,45 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp\Formatter;
-
-use Leafo\ScssPhp\Formatter;
-
-/**
- * Compact formatter
- *
- * @author Leaf Corcoran <leafot@gmail.com>
- */
-class Compact extends Formatter
-{
-    /**
-     * {@inheritdoc}
-     */
-    public function __construct()
-    {
-        $this->indentLevel = 0;
-        $this->indentChar = '';
-        $this->break = '';
-        $this->open = ' {';
-        $this->close = "}\n\n";
-        $this->tagSeparator = ',';
-        $this->assignSeparator = ':';
-        $this->keepSemicolons = true;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function indentStr()
-    {
-        return ' ';
-    }
-}
diff --git a/inc/scssphp--old/src/Formatter/Compressed.php b/inc/scssphp--old/src/Formatter/Compressed.php
deleted file mode 100644
index 1faa7e1..0000000
--- a/inc/scssphp--old/src/Formatter/Compressed.php
+++ /dev/null
@@ -1,62 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp\Formatter;
-
-use Leafo\ScssPhp\Formatter;
-use Leafo\ScssPhp\Formatter\OutputBlock;
-
-/**
- * Compressed formatter
- *
- * @author Leaf Corcoran <leafot@gmail.com>
- */
-class Compressed extends Formatter
-{
-    /**
-     * {@inheritdoc}
-     */
-    public function __construct()
-    {
-        $this->indentLevel = 0;
-        $this->indentChar = '  ';
-        $this->break = '';
-        $this->open = '{';
-        $this->close = '}';
-        $this->tagSeparator = ',';
-        $this->assignSeparator = ':';
-        $this->keepSemicolons = false;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function blockLines(OutputBlock $block)
-    {
-        $inner = $this->indentStr();
-
-        $glue = $this->break . $inner;
-
-        foreach ($block->lines as $index => $line) {
-            if (substr($line, 0, 2) === '/*' && substr($line, 2, 1) !== '!') {
-                unset($block->lines[$index]);
-            } elseif (substr($line, 0, 3) === '/*!') {
-                $block->lines[$index] = '/*' . substr($line, 3);
-            }
-        }
-
-        $this->write($inner . implode($glue, $block->lines));
-
-        if (! empty($block->children)) {
-            $this->write($this->break);
-        }
-    }
-}
diff --git a/inc/scssphp--old/src/Formatter/Crunched.php b/inc/scssphp--old/src/Formatter/Crunched.php
deleted file mode 100644
index 42d77b5..0000000
--- a/inc/scssphp--old/src/Formatter/Crunched.php
+++ /dev/null
@@ -1,60 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp\Formatter;
-
-use Leafo\ScssPhp\Formatter;
-use Leafo\ScssPhp\Formatter\OutputBlock;
-
-/**
- * Crunched formatter
- *
- * @author Anthon Pang <anthon.pang@gmail.com>
- */
-class Crunched extends Formatter
-{
-    /**
-     * {@inheritdoc}
-     */
-    public function __construct()
-    {
-        $this->indentLevel = 0;
-        $this->indentChar = '  ';
-        $this->break = '';
-        $this->open = '{';
-        $this->close = '}';
-        $this->tagSeparator = ',';
-        $this->assignSeparator = ':';
-        $this->keepSemicolons = false;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function blockLines(OutputBlock $block)
-    {
-        $inner = $this->indentStr();
-
-        $glue = $this->break . $inner;
-
-        foreach ($block->lines as $index => $line) {
-            if (substr($line, 0, 2) === '/*') {
-                unset($block->lines[$index]);
-            }
-        }
-
-        $this->write($inner . implode($glue, $block->lines));
-
-        if (! empty($block->children)) {
-            $this->write($this->break);
-        }
-    }
-}
diff --git a/inc/scssphp--old/src/Formatter/Debug.php b/inc/scssphp--old/src/Formatter/Debug.php
deleted file mode 100644
index bfcbf41..0000000
--- a/inc/scssphp--old/src/Formatter/Debug.php
+++ /dev/null
@@ -1,121 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp\Formatter;
-
-use Leafo\ScssPhp\Formatter;
-use Leafo\ScssPhp\Formatter\OutputBlock;
-
-/**
- * Debug formatter
- *
- * @author Anthon Pang <anthon.pang@gmail.com>
- */
-class Debug extends Formatter
-{
-    /**
-     * {@inheritdoc}
-     */
-    public function __construct()
-    {
-        $this->indentLevel = 0;
-        $this->indentChar = '';
-        $this->break = "\n";
-        $this->open = ' {';
-        $this->close = ' }';
-        $this->tagSeparator = ', ';
-        $this->assignSeparator = ': ';
-        $this->keepSemicolons = true;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    protected function indentStr()
-    {
-        return str_repeat('  ', $this->indentLevel);
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    protected function blockLines(OutputBlock $block)
-    {
-        $indent = $this->indentStr();
-
-        if (empty($block->lines)) {
-            $this->write("{$indent}block->lines: []\n");
-
-            return;
-        }
-
-        foreach ($block->lines as $index => $line) {
-            $this->write("{$indent}block->lines[{$index}]: $line\n");
-        }
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    protected function blockSelectors(OutputBlock $block)
-    {
-        $indent = $this->indentStr();
-
-        if (empty($block->selectors)) {
-            $this->write("{$indent}block->selectors: []\n");
-
-            return;
-        }
-
-        foreach ($block->selectors as $index => $selector) {
-            $this->write("{$indent}block->selectors[{$index}]: $selector\n");
-        }
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    protected function blockChildren(OutputBlock $block)
-    {
-        $indent = $this->indentStr();
-
-        if (empty($block->children)) {
-            $this->write("{$indent}block->children: []\n");
-
-            return;
-        }
-
-        $this->indentLevel++;
-
-        foreach ($block->children as $i => $child) {
-            $this->block($child);
-        }
-
-        $this->indentLevel--;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    protected function block(OutputBlock $block)
-    {
-        $indent = $this->indentStr();
-
-        $this->write("{$indent}block->type: {$block->type}\n" .
-             "{$indent}block->depth: {$block->depth}\n");
-
-        $this->currentBlock = $block;
-
-        $this->blockSelectors($block);
-        $this->blockLines($block);
-        $this->blockChildren($block);
-    }
-}
diff --git a/inc/scssphp--old/src/Formatter/Expanded.php b/inc/scssphp--old/src/Formatter/Expanded.php
deleted file mode 100644
index d8c1e88..0000000
--- a/inc/scssphp--old/src/Formatter/Expanded.php
+++ /dev/null
@@ -1,68 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp\Formatter;
-
-use Leafo\ScssPhp\Formatter;
-use Leafo\ScssPhp\Formatter\OutputBlock;
-
-/**
- * Expanded formatter
- *
- * @author Leaf Corcoran <leafot@gmail.com>
- */
-class Expanded extends Formatter
-{
-    /**
-     * {@inheritdoc}
-     */
-    public function __construct()
-    {
-        $this->indentLevel = 0;
-        $this->indentChar = '  ';
-        $this->break = "\n";
-        $this->open = ' {';
-        $this->close = '}';
-        $this->tagSeparator = ', ';
-        $this->assignSeparator = ': ';
-        $this->keepSemicolons = true;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    protected function indentStr()
-    {
-        return str_repeat($this->indentChar, $this->indentLevel);
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    protected function blockLines(OutputBlock $block)
-    {
-        $inner = $this->indentStr();
-
-        $glue = $this->break . $inner;
-
-        foreach ($block->lines as $index => $line) {
-            if (substr($line, 0, 2) === '/*') {
-                $block->lines[$index] = preg_replace('/(\r|\n)+/', $glue, $line);
-            }
-        }
-
-        $this->write($inner . implode($glue, $block->lines));
-
-        if (empty($block->selectors) || ! empty($block->children)) {
-            $this->write($this->break);
-        }
-    }
-}
diff --git a/inc/scssphp--old/src/Formatter/Nested.php b/inc/scssphp--old/src/Formatter/Nested.php
deleted file mode 100644
index 8f72206..0000000
--- a/inc/scssphp--old/src/Formatter/Nested.php
+++ /dev/null
@@ -1,201 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp\Formatter;
-
-use Leafo\ScssPhp\Formatter;
-use Leafo\ScssPhp\Formatter\OutputBlock;
-
-/**
- * Nested formatter
- *
- * @author Leaf Corcoran <leafot@gmail.com>
- */
-class Nested extends Formatter
-{
-    /**
-     * @var integer
-     */
-    private $depth;
-
-    /**
-     * {@inheritdoc}
-     */
-    public function __construct()
-    {
-        $this->indentLevel = 0;
-        $this->indentChar = '  ';
-        $this->break = "\n";
-        $this->open = ' {';
-        $this->close = ' }';
-        $this->tagSeparator = ', ';
-        $this->assignSeparator = ': ';
-        $this->keepSemicolons = true;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    protected function indentStr()
-    {
-        $n = $this->depth - 1;
-
-        return str_repeat($this->indentChar, max($this->indentLevel + $n, 0));
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    protected function blockLines(OutputBlock $block)
-    {
-        $inner = $this->indentStr();
-
-        $glue = $this->break . $inner;
-
-        foreach ($block->lines as $index => $line) {
-            if (substr($line, 0, 2) === '/*') {
-                $block->lines[$index] = preg_replace('/(\r|\n)+/', $glue, $line);
-            }
-        }
-
-        $this->write($inner . implode($glue, $block->lines));
-
-        if (! empty($block->children)) {
-            $this->write($this->break);
-        }
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    protected function blockSelectors(OutputBlock $block)
-    {
-        $inner = $this->indentStr();
-
-        $this->write($inner
-            . implode($this->tagSeparator, $block->selectors)
-            . $this->open . $this->break);
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    protected function blockChildren(OutputBlock $block)
-    {
-        foreach ($block->children as $i => $child) {
-            $this->block($child);
-
-            if ($i < count($block->children) - 1) {
-                $this->write($this->break);
-
-                if (isset($block->children[$i + 1])) {
-                    $next = $block->children[$i + 1];
-
-                    if ($next->depth === max($block->depth, 1) && $child->depth >= $next->depth) {
-                        $this->write($this->break);
-                    }
-                }
-            }
-        }
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    protected function block(OutputBlock $block)
-    {
-        if ($block->type === 'root') {
-            $this->adjustAllChildren($block);
-        }
-
-        if (empty($block->lines) && empty($block->children)) {
-            return;
-        }
-
-        $this->currentBlock = $block;
-
-
-        $this->depth = $block->depth;
-
-        if (! empty($block->selectors)) {
-            $this->blockSelectors($block);
-
-            $this->indentLevel++;
-        }
-
-        if (! empty($block->lines)) {
-            $this->blockLines($block);
-        }
-
-        if (! empty($block->children)) {
-            $this->blockChildren($block);
-        }
-
-        if (! empty($block->selectors)) {
-            $this->indentLevel--;
-
-            $this->write($this->close);
-        }
-
-        if ($block->type === 'root') {
-            $this->write($this->break);
-        }
-    }
-
-    /**
-     * Adjust the depths of all children, depth first
-     *
-     * @param \Leafo\ScssPhp\Formatter\OutputBlock $block
-     */
-    private function adjustAllChildren(OutputBlock $block)
-    {
-        // flatten empty nested blocks
-        $children = [];
-
-        foreach ($block->children as $i => $child) {
-            if (empty($child->lines) && empty($child->children)) {
-                if (isset($block->children[$i + 1])) {
-                    $block->children[$i + 1]->depth = $child->depth;
-                }
-
-                continue;
-            }
-
-            $children[] = $child;
-        }
-
-        $count = count($children);
-
-        for ($i = 0; $i < $count; $i++) {
-            $depth = $children[$i]->depth;
-            $j = $i + 1;
-
-            if (isset($children[$j]) && $depth < $children[$j]->depth) {
-                $childDepth = $children[$j]->depth;
-
-                for (; $j < $count; $j++) {
-                    if ($depth < $children[$j]->depth && $childDepth >= $children[$j]->depth) {
-                        $children[$j]->depth = $depth + 1;
-                    }
-                }
-            }
-        }
-
-        $block->children = $children;
-
-        // make relative to parent
-        foreach ($block->children as $child) {
-            $this->adjustAllChildren($child);
-
-            $child->depth = $child->depth - $block->depth;
-        }
-    }
-}
diff --git a/inc/scssphp--old/src/Formatter/OutputBlock.php b/inc/scssphp--old/src/Formatter/OutputBlock.php
deleted file mode 100644
index 5eb589c..0000000
--- a/inc/scssphp--old/src/Formatter/OutputBlock.php
+++ /dev/null
@@ -1,65 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp\Formatter;
-
-/**
- * Output block
- *
- * @author Anthon Pang <anthon.pang@gmail.com>
- */
-class OutputBlock
-{
-    /**
-     * @var string
-     */
-    public $type;
-
-    /**
-     * @var integer
-     */
-    public $depth;
-
-    /**
-     * @var array
-     */
-    public $selectors;
-
-    /**
-     * @var array
-     */
-    public $lines;
-
-    /**
-     * @var array
-     */
-    public $children;
-
-    /**
-     * @var \Leafo\ScssPhp\Formatter\OutputBlock
-     */
-    public $parent;
-
-    /**
-     * @var string
-     */
-    public $sourceName;
-
-    /**
-     * @var integer
-     */
-    public $sourceLine;
-
-    /**
-     * @var integer
-     */
-    public $sourceColumn;
-}
diff --git a/inc/scssphp--old/src/Node.php b/inc/scssphp--old/src/Node.php
deleted file mode 100644
index b9f7945..0000000
--- a/inc/scssphp--old/src/Node.php
+++ /dev/null
@@ -1,40 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp;
-
-/**
- * Base node
- *
- * @author Anthon Pang <anthon.pang@gmail.com>
- */
-abstract class Node
-{
-    /**
-     * @var string
-     */
-    public $type;
-
-    /**
-     * @var integer
-     */
-    public $sourceIndex;
-
-    /**
-     * @var integer
-     */
-    public $sourceLine;
-
-    /**
-     * @var integer
-     */
-    public $sourceColumn;
-}
diff --git a/inc/scssphp--old/src/Node/Number.php b/inc/scssphp--old/src/Node/Number.php
deleted file mode 100644
index 42c1680..0000000
--- a/inc/scssphp--old/src/Node/Number.php
+++ /dev/null
@@ -1,330 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp\Node;
-
-use Leafo\ScssPhp\Compiler;
-use Leafo\ScssPhp\Node;
-use Leafo\ScssPhp\Type;
-
-/**
- * Dimension + optional units
- *
- * {@internal
- *     This is a work-in-progress.
- *
- *     The \ArrayAccess interface is temporary until the migration is complete.
- * }}
- *
- * @author Anthon Pang <anthon.pang@gmail.com>
- */
-class Number extends Node implements \ArrayAccess
-{
-    /**
-     * @var integer
-     */
-    static public $precision = 10;
-
-    /**
-     * @see http://www.w3.org/TR/2012/WD-css3-values-20120308/
-     *
-     * @var array
-     */
-    static protected $unitTable = [
-        'in' => [
-            'in' => 1,
-            'pc' => 6,
-            'pt' => 72,
-            'px' => 96,
-            'cm' => 2.54,
-            'mm' => 25.4,
-            'q'  => 101.6,
-        ],
-        'turn' => [
-            'deg'  => 360,
-            'grad' => 400,
-            'rad'  => 6.28318530717958647692528676, // 2 * M_PI
-            'turn' => 1,
-        ],
-        's' => [
-            's'  => 1,
-            'ms' => 1000,
-        ],
-        'Hz' => [
-            'Hz'  => 1,
-            'kHz' => 0.001,
-        ],
-        'dpi' => [
-            'dpi'  => 1,
-            'dpcm' => 2.54,
-            'dppx' => 96,
-        ],
-    ];
-
-    /**
-     * @var integer|float
-     */
-    public $dimension;
-
-    /**
-     * @var array
-     */
-    public $units;
-
-    /**
-     * Initialize number
-     *
-     * @param mixed $dimension
-     * @param mixed $initialUnit
-     */
-    public function __construct($dimension, $initialUnit)
-    {
-        $this->type      = Type::T_NUMBER;
-        $this->dimension = $dimension;
-        $this->units     = is_array($initialUnit)
-            ? $initialUnit
-            : ($initialUnit ? [$initialUnit => 1]
-                            : []);
-    }
-
-    /**
-     * Coerce number to target units
-     *
-     * @param array $units
-     *
-     * @return \Leafo\ScssPhp\Node\Number
-     */
-    public function coerce($units)
-    {
-        if ($this->unitless()) {
-            return new Number($this->dimension, $units);
-        }
-
-        $dimension = $this->dimension;
-
-        foreach (static::$unitTable['in'] as $unit => $conv) {
-            $from       = isset($this->units[$unit]) ? $this->units[$unit] : 0;
-            $to         = isset($units[$unit]) ? $units[$unit] : 0;
-            $factor     = pow($conv, $from - $to);
-            $dimension /= $factor;
-        }
-
-        return new Number($dimension, $units);
-    }
-
-    /**
-     * Normalize number
-     *
-     * @return \Leafo\ScssPhp\Node\Number
-     */
-    public function normalize()
-    {
-        $dimension = $this->dimension;
-        $units     = [];
-
-        $this->normalizeUnits($dimension, $units, 'in');
-
-        return new Number($dimension, $units);
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function offsetExists($offset)
-    {
-        if ($offset === -3) {
-            return $this->sourceColumn !== null;
-        }
-
-        if ($offset === -2) {
-            return $this->sourceLine !== null;
-        }
-
-        if ($offset === -1
-            || $offset === 0
-            || $offset === 1
-            || $offset === 2
-        ) {
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function offsetGet($offset)
-    {
-        switch ($offset) {
-            case -3:
-                return $this->sourceColumn;
-
-            case -2:
-                return $this->sourceLine;
-
-            case -1:
-                return $this->sourceIndex;
-
-            case 0:
-                return $this->type;
-
-            case 1:
-                return $this->dimension;
-
-            case 2:
-                return $this->units;
-        }
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function offsetSet($offset, $value)
-    {
-        if ($offset === 1) {
-            $this->dimension = $value;
-        } elseif ($offset === 2) {
-            $this->units = $value;
-        } elseif ($offset == -1) {
-            $this->sourceIndex = $value;
-        } elseif ($offset == -2) {
-            $this->sourceLine = $value;
-        } elseif ($offset == -3) {
-            $this->sourceColumn = $value;
-        }
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function offsetUnset($offset)
-    {
-        if ($offset === 1) {
-            $this->dimension = null;
-        } elseif ($offset === 2) {
-            $this->units = null;
-        } elseif ($offset === -1) {
-            $this->sourceIndex = null;
-        } elseif ($offset === -2) {
-            $this->sourceLine = null;
-        } elseif ($offset === -3) {
-            $this->sourceColumn = null;
-        }
-    }
-
-    /**
-     * Returns true if the number is unitless
-     *
-     * @return boolean
-     */
-    public function unitless()
-    {
-        return ! array_sum($this->units);
-    }
-
-    /**
-     * Returns unit(s) as the product of numerator units divided by the product of denominator units
-     *
-     * @return string
-     */
-    public function unitStr()
-    {
-        $numerators   = [];
-        $denominators = [];
-
-        foreach ($this->units as $unit => $unitSize) {
-            if ($unitSize > 0) {
-                $numerators = array_pad($numerators, count($numerators) + $unitSize, $unit);
-                continue;
-            }
-
-            if ($unitSize < 0) {
-                $denominators = array_pad($denominators, count($denominators) + $unitSize, $unit);
-                continue;
-            }
-        }
-
-        return implode('*', $numerators) . (count($denominators) ? '/' . implode('*', $denominators) : '');
-    }
-
-    /**
-     * Output number
-     *
-     * @param \Leafo\ScssPhp\Compiler $compiler
-     *
-     * @return string
-     */
-    public function output(Compiler $compiler = null)
-    {
-        $dimension = round($this->dimension, static::$precision);
-
-        $units = array_filter($this->units, function ($unitSize) {
-            return $unitSize;
-        });
-
-        if (count($units) > 1 && array_sum($units) === 0) {
-            $dimension = $this->dimension;
-            $units     = [];
-
-            $this->normalizeUnits($dimension, $units, 'in');
-
-            $dimension = round($dimension, static::$precision);
-            $units     = array_filter($units, function ($unitSize) {
-                return $unitSize;
-            });
-        }
-
-        $unitSize = array_sum($units);
-
-        if ($compiler && ($unitSize > 1 || $unitSize < 0 || count($units) > 1)) {
-            $compiler->throwError((string) $dimension . $this->unitStr() . " isn't a valid CSS value.");
-        }
-
-        reset($units);
-        $unit = key($units);
-        $dimension = number_format($dimension, static::$precision, '.', '');
-
-        return (static::$precision ? rtrim(rtrim($dimension, '0'), '.') : $dimension) . $unit;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function __toString()
-    {
-        return $this->output();
-    }
-
-    /**
-     * Normalize units
-     *
-     * @param integer|float $dimension
-     * @param array         $units
-     * @param string        $baseUnit
-     */
-    private function normalizeUnits(&$dimension, &$units, $baseUnit = 'in')
-    {
-        $dimension = $this->dimension;
-        $units     = [];
-
-        foreach ($this->units as $unit => $exp) {
-            if (isset(static::$unitTable[$baseUnit][$unit])) {
-                $factor = pow(static::$unitTable[$baseUnit][$unit], $exp);
-
-                $unit = $baseUnit;
-                $dimension /= $factor;
-            }
-
-            $units[$unit] = $exp + (isset($units[$unit]) ? $units[$unit] : 0);
-        }
-    }
-}
diff --git a/inc/scssphp--old/src/Parser.php b/inc/scssphp--old/src/Parser.php
deleted file mode 100644
index 6fdea3e..0000000
--- a/inc/scssphp--old/src/Parser.php
+++ /dev/null
@@ -1,2494 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp;
-
-use Leafo\ScssPhp\Block;
-use Leafo\ScssPhp\Compiler;
-use Leafo\ScssPhp\Exception\ParserException;
-use Leafo\ScssPhp\Node;
-use Leafo\ScssPhp\Type;
-
-/**
- * Parser
- *
- * @author Leaf Corcoran <leafot@gmail.com>
- */
-class Parser
-{
-    const SOURCE_INDEX  = -1;
-    const SOURCE_LINE   = -2;
-    const SOURCE_COLUMN = -3;
-
-    /**
-     * @var array
-     */
-    protected static $precedence = [
-        '='   => 0,
-        'or'  => 1,
-        'and' => 2,
-        '=='  => 3,
-        '!='  => 3,
-        '<=>' => 3,
-        '<='  => 4,
-        '>='  => 4,
-        '<'   => 4,
-        '>'   => 4,
-        '+'   => 5,
-        '-'   => 5,
-        '*'   => 6,
-        '/'   => 6,
-        '%'   => 6,
-    ];
-
-    protected static $commentPattern;
-    protected static $operatorPattern;
-    protected static $whitePattern;
-
-    private $sourceName;
-    private $sourceIndex;
-    private $sourcePositions;
-    private $charset;
-    private $count;
-    private $env;
-    private $inParens;
-    private $eatWhiteDefault;
-    private $buffer;
-    private $utf8;
-    private $encoding;
-    private $patternModifiers;
-
-    /**
-     * Constructor
-     *
-     * @api
-     *
-     * @param string  $sourceName
-     * @param integer $sourceIndex
-     * @param string  $encoding
-     */
-    public function __construct($sourceName, $sourceIndex = 0, $encoding = 'utf-8')
-    {
-        $this->sourceName       = $sourceName ?: '(stdin)';
-        $this->sourceIndex      = $sourceIndex;
-        $this->charset          = null;
-        $this->utf8             = ! $encoding || strtolower($encoding) === 'utf-8';
-        $this->patternModifiers = $this->utf8 ? 'Aisu' : 'Ais';
-
-        if (empty(static::$operatorPattern)) {
-            static::$operatorPattern = '([*\/%+-]|[!=]\=|\>\=?|\<\=\>|\<\=?|and|or)';
-
-            $commentSingle      = '\/\/';
-            $commentMultiLeft   = '\/\*';
-            $commentMultiRight  = '\*\/';
-
-            static::$commentPattern = $commentMultiLeft . '.*?' . $commentMultiRight;
-            static::$whitePattern = $this->utf8
-                ? '/' . $commentSingle . '[^\n]*\s*|(' . static::$commentPattern . ')\s*|\s+/AisuS'
-                : '/' . $commentSingle . '[^\n]*\s*|(' . static::$commentPattern . ')\s*|\s+/AisS';
-        }
-    }
-
-    /**
-     * Get source file name
-     *
-     * @api
-     *
-     * @return string
-     */
-    public function getSourceName()
-    {
-        return $this->sourceName;
-    }
-
-    /**
-     * Throw parser error
-     *
-     * @api
-     *
-     * @param string $msg
-     *
-     * @throws \Leafo\ScssPhp\Exception\ParserException
-     */
-    public function throwParseError($msg = 'parse error')
-    {
-        list($line, /* $column */) = $this->getSourcePosition($this->count);
-
-        $loc = empty($this->sourceName) ? "line: $line" : "$this->sourceName on line $line";
-
-        if ($this->peek("(.*?)(\n|$)", $m, $this->count)) {
-            throw new ParserException("$msg: failed at `$m[1]` $loc");
-        }
-
-        throw new ParserException("$msg: $loc");
-    }
-
-    /**
-     * Parser buffer
-     *
-     * @api
-     *
-     * @param string $buffer
-     *
-     * @return \Leafo\ScssPhp\Block
-     */
-    public function parse($buffer)
-    {
-        // strip BOM (byte order marker)
-        if (substr($buffer, 0, 3) === "\xef\xbb\xbf") {
-            $buffer = substr($buffer, 3);
-        }
-
-        $this->buffer          = rtrim($buffer, "\x00..\x1f");
-        $this->count           = 0;
-        $this->env             = null;
-        $this->inParens        = false;
-        $this->eatWhiteDefault = true;
-
-        $this->saveEncoding();
-        $this->extractLineNumbers($buffer);
-
-        $this->pushBlock(null); // root block
-        $this->whitespace();
-        $this->pushBlock(null);
-        $this->popBlock();
-
-        while ($this->parseChunk()) {
-            ;
-        }
-
-        if ($this->count !== strlen($this->buffer)) {
-            $this->throwParseError();
-        }
-
-        if (! empty($this->env->parent)) {
-            $this->throwParseError('unclosed block');
-        }
-
-        if ($this->charset) {
-            array_unshift($this->env->children, $this->charset);
-        }
-
-        $this->env->isRoot    = true;
-
-        $this->restoreEncoding();
-
-        return $this->env;
-    }
-
-    /**
-     * Parse a value or value list
-     *
-     * @api
-     *
-     * @param string $buffer
-     * @param string $out
-     *
-     * @return boolean
-     */
-    public function parseValue($buffer, &$out)
-    {
-        $this->count           = 0;
-        $this->env             = null;
-        $this->inParens        = false;
-        $this->eatWhiteDefault = true;
-        $this->buffer          = (string) $buffer;
-
-        $this->saveEncoding();
-
-        $list = $this->valueList($out);
-
-        $this->restoreEncoding();
-
-        return $list;
-    }
-
-    /**
-     * Parse a selector or selector list
-     *
-     * @api
-     *
-     * @param string $buffer
-     * @param string $out
-     *
-     * @return boolean
-     */
-    public function parseSelector($buffer, &$out)
-    {
-        $this->count           = 0;
-        $this->env             = null;
-        $this->inParens        = false;
-        $this->eatWhiteDefault = true;
-        $this->buffer          = (string) $buffer;
-
-        $this->saveEncoding();
-
-        $selector = $this->selectors($out);
-
-        $this->restoreEncoding();
-
-        return $selector;
-    }
-
-    /**
-     * Parse a single chunk off the head of the buffer and append it to the
-     * current parse environment.
-     *
-     * Returns false when the buffer is empty, or when there is an error.
-     *
-     * This function is called repeatedly until the entire document is
-     * parsed.
-     *
-     * This parser is most similar to a recursive descent parser. Single
-     * functions represent discrete grammatical rules for the language, and
-     * they are able to capture the text that represents those rules.
-     *
-     * Consider the function Compiler::keyword(). (All parse functions are
-     * structured the same.)
-     *
-     * The function takes a single reference argument. When calling the
-     * function it will attempt to match a keyword on the head of the buffer.
-     * If it is successful, it will place the keyword in the referenced
-     * argument, advance the position in the buffer, and return true. If it
-     * fails then it won't advance the buffer and it will return false.
-     *
-     * All of these parse functions are powered by Compiler::match(), which behaves
-     * the same way, but takes a literal regular expression. Sometimes it is
-     * more convenient to use match instead of creating a new function.
-     *
-     * Because of the format of the functions, to parse an entire string of
-     * grammatical rules, you can chain them together using &&.
-     *
-     * But, if some of the rules in the chain succeed before one fails, then
-     * the buffer position will be left at an invalid state. In order to
-     * avoid this, Compiler::seek() is used to remember and set buffer positions.
-     *
-     * Before parsing a chain, use $s = $this->seek() to remember the current
-     * position into $s. Then if a chain fails, use $this->seek($s) to
-     * go back where we started.
-     *
-     * @return boolean
-     */
-    protected function parseChunk()
-    {
-        $s = $this->seek();
-
-        // the directives
-        if (isset($this->buffer[$this->count]) && $this->buffer[$this->count] === '@') {
-            if ($this->literal('@at-root') &&
-                ($this->selectors($selector) || true) &&
-                ($this->map($with) || true) &&
-                $this->literal('{')
-            ) {
-                $atRoot = $this->pushSpecialBlock(Type::T_AT_ROOT, $s);
-                $atRoot->selector = $selector;
-                $atRoot->with = $with;
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@media') && $this->mediaQueryList($mediaQueryList) && $this->literal('{')) {
-                $media = $this->pushSpecialBlock(Type::T_MEDIA, $s);
-                $media->queryList = $mediaQueryList[2];
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@mixin') &&
-                $this->keyword($mixinName) &&
-                ($this->argumentDef($args) || true) &&
-                $this->literal('{')
-            ) {
-                $mixin = $this->pushSpecialBlock(Type::T_MIXIN, $s);
-                $mixin->name = $mixinName;
-                $mixin->args = $args;
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@include') &&
-                $this->keyword($mixinName) &&
-                ($this->literal('(') &&
-                    ($this->argValues($argValues) || true) &&
-                    $this->literal(')') || true) &&
-                ($this->end() ||
-                    $this->literal('{') && $hasBlock = true)
-            ) {
-                $child = [Type::T_INCLUDE, $mixinName, isset($argValues) ? $argValues : null, null];
-
-                if (! empty($hasBlock)) {
-                    $include = $this->pushSpecialBlock(Type::T_INCLUDE, $s);
-                    $include->child = $child;
-                } else {
-                    $this->append($child, $s);
-                }
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@scssphp-import-once') &&
-                $this->valueList($importPath) &&
-                $this->end()
-            ) {
-                $this->append([Type::T_SCSSPHP_IMPORT_ONCE, $importPath], $s);
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@import') &&
-                $this->valueList($importPath) &&
-                $this->end()
-            ) {
-                $this->append([Type::T_IMPORT, $importPath], $s);
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@import') &&
-                $this->url($importPath) &&
-                $this->end()
-            ) {
-                $this->append([Type::T_IMPORT, $importPath], $s);
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@extend') &&
-                $this->selectors($selectors) &&
-                $this->end()
-            ) {
-                // check for '!flag'
-                $optional = $this->stripOptionalFlag($selectors);
-                $this->append([Type::T_EXTEND, $selectors, $optional], $s);
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@function') &&
-                $this->keyword($fnName) &&
-                $this->argumentDef($args) &&
-                $this->literal('{')
-            ) {
-                $func = $this->pushSpecialBlock(Type::T_FUNCTION, $s);
-                $func->name = $fnName;
-                $func->args = $args;
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@break') && $this->end()) {
-                $this->append([Type::T_BREAK], $s);
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@continue') && $this->end()) {
-                $this->append([Type::T_CONTINUE], $s);
-
-                return true;
-            }
-
-            $this->seek($s);
-
-
-            if ($this->literal('@return') && ($this->valueList($retVal) || true) && $this->end()) {
-                $this->append([Type::T_RETURN, isset($retVal) ? $retVal : [Type::T_NULL]], $s);
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@each') &&
-                $this->genericList($varNames, 'variable', ',', false) &&
-                $this->literal('in') &&
-                $this->valueList($list) &&
-                $this->literal('{')
-            ) {
-                $each = $this->pushSpecialBlock(Type::T_EACH, $s);
-
-                foreach ($varNames[2] as $varName) {
-                    $each->vars[] = $varName[1];
-                }
-
-                $each->list = $list;
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@while') &&
-                $this->expression($cond) &&
-                $this->literal('{')
-            ) {
-                $while = $this->pushSpecialBlock(Type::T_WHILE, $s);
-                $while->cond = $cond;
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@for') &&
-                $this->variable($varName) &&
-                $this->literal('from') &&
-                $this->expression($start) &&
-                ($this->literal('through') ||
-                    ($forUntil = true && $this->literal('to'))) &&
-                $this->expression($end) &&
-                $this->literal('{')
-            ) {
-                $for = $this->pushSpecialBlock(Type::T_FOR, $s);
-                $for->var = $varName[1];
-                $for->start = $start;
-                $for->end = $end;
-                $for->until = isset($forUntil);
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@if') && $this->valueList($cond) && $this->literal('{')) {
-                $if = $this->pushSpecialBlock(Type::T_IF, $s);
-                $if->cond = $cond;
-                $if->cases = [];
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@debug') &&
-                $this->valueList($value) &&
-                $this->end()
-            ) {
-                $this->append([Type::T_DEBUG, $value], $s);
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@warn') &&
-                $this->valueList($value) &&
-                $this->end()
-            ) {
-                $this->append([Type::T_WARN, $value], $s);
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@error') &&
-                $this->valueList($value) &&
-                $this->end()
-            ) {
-                $this->append([Type::T_ERROR, $value], $s);
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->literal('@content') && $this->end()) {
-                $this->append([Type::T_MIXIN_CONTENT], $s);
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            $last = $this->last();
-
-            if (isset($last) && $last[0] === Type::T_IF) {
-                list(, $if) = $last;
-
-                if ($this->literal('@else')) {
-                    if ($this->literal('{')) {
-                        $else = $this->pushSpecialBlock(Type::T_ELSE, $s);
-                    } elseif ($this->literal('if') && $this->valueList($cond) && $this->literal('{')) {
-                        $else = $this->pushSpecialBlock(Type::T_ELSEIF, $s);
-                        $else->cond = $cond;
-                    }
-
-                    if (isset($else)) {
-                        $else->dontAppend = true;
-                        $if->cases[] = $else;
-
-                        return true;
-                    }
-                }
-
-                $this->seek($s);
-            }
-
-            // only retain the first @charset directive encountered
-            if ($this->literal('@charset') &&
-                $this->valueList($charset) &&
-                $this->end()
-            ) {
-                if (! isset($this->charset)) {
-                    $statement = [Type::T_CHARSET, $charset];
-
-                    list($line, $column) = $this->getSourcePosition($s);
-
-                    $statement[static::SOURCE_LINE]   = $line;
-                    $statement[static::SOURCE_COLUMN] = $column;
-                    $statement[static::SOURCE_INDEX]  = $this->sourceIndex;
-
-                    $this->charset = $statement;
-                }
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            // doesn't match built in directive, do generic one
-            if ($this->literal('@', false) &&
-                $this->keyword($dirName) &&
-                ($this->variable($dirValue) || $this->openString('{', $dirValue) || true) &&
-                $this->literal('{')
-            ) {
-                if ($dirName === 'media') {
-                    $directive = $this->pushSpecialBlock(Type::T_MEDIA, $s);
-                } else {
-                    $directive = $this->pushSpecialBlock(Type::T_DIRECTIVE, $s);
-                    $directive->name = $dirName;
-                }
-
-                if (isset($dirValue)) {
-                    $directive->value = $dirValue;
-                }
-
-                return true;
-            }
-
-            $this->seek($s);
-
-            return false;
-        }
-
-        // property shortcut
-        // captures most properties before having to parse a selector
-        if ($this->keyword($name, false) &&
-            $this->literal(': ') &&
-            $this->valueList($value) &&
-            $this->end()
-        ) {
-            $name = [Type::T_STRING, '', [$name]];
-            $this->append([Type::T_ASSIGN, $name, $value], $s);
-
-            return true;
-        }
-
-        $this->seek($s);
-
-        // variable assigns
-        if ($this->variable($name) &&
-            $this->literal(':') &&
-            $this->valueList($value) &&
-            $this->end()
-        ) {
-            // check for '!flag'
-            $assignmentFlags = $this->stripAssignmentFlags($value);
-            $this->append([Type::T_ASSIGN, $name, $value, $assignmentFlags], $s);
-
-            return true;
-        }
-
-        $this->seek($s);
-
-        // misc
-        if ($this->literal('-->')) {
-            return true;
-        }
-
-        // opening css block
-        if ($this->selectors($selectors) && $this->literal('{')) {
-            $this->pushBlock($selectors, $s);
-
-            return true;
-        }
-
-        $this->seek($s);
-
-        // property assign, or nested assign
-        if ($this->propertyName($name) && $this->literal(':')) {
-            $foundSomething = false;
-
-            if ($this->valueList($value)) {
-                $this->append([Type::T_ASSIGN, $name, $value], $s);
-                $foundSomething = true;
-            }
-
-            if ($this->literal('{')) {
-                $propBlock = $this->pushSpecialBlock(Type::T_NESTED_PROPERTY, $s);
-                $propBlock->prefix = $name;
-                $foundSomething = true;
-            } elseif ($foundSomething) {
-                $foundSomething = $this->end();
-            }
-
-            if ($foundSomething) {
-                return true;
-            }
-        }
-
-        $this->seek($s);
-
-        // closing a block
-        if ($this->literal('}')) {
-            $block = $this->popBlock();
-
-            if (isset($block->type) && $block->type === Type::T_INCLUDE) {
-                $include = $block->child;
-                unset($block->child);
-                $include[3] = $block;
-                $this->append($include, $s);
-            } elseif (empty($block->dontAppend)) {
-                $type = isset($block->type) ? $block->type : Type::T_BLOCK;
-                $this->append([$type, $block], $s);
-            }
-
-            return true;
-        }
-
-        // extra stuff
-        if ($this->literal(';') ||
-            $this->literal('<!--')
-        ) {
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Push block onto parse tree
-     *
-     * @param array   $selectors
-     * @param integer $pos
-     *
-     * @return \Leafo\ScssPhp\Block
-     */
-    protected function pushBlock($selectors, $pos = 0)
-    {
-        list($line, $column) = $this->getSourcePosition($pos);
-
-        $b = new Block;
-        $b->sourceName   = $this->sourceName;
-        $b->sourceLine   = $line;
-        $b->sourceColumn = $column;
-        $b->sourceIndex  = $this->sourceIndex;
-        $b->selectors    = $selectors;
-        $b->comments     = [];
-        $b->parent       = $this->env;
-
-        if (! $this->env) {
-            $b->children = [];
-        } elseif (empty($this->env->children)) {
-            $this->env->children = $this->env->comments;
-            $b->children = [];
-            $this->env->comments = [];
-        } else {
-            $b->children = $this->env->comments;
-            $this->env->comments = [];
-        }
-
-        $this->env = $b;
-
-        return $b;
-    }
-
-    /**
-     * Push special (named) block onto parse tree
-     *
-     * @param string  $type
-     * @param integer $pos
-     *
-     * @return \Leafo\ScssPhp\Block
-     */
-    protected function pushSpecialBlock($type, $pos)
-    {
-        $block = $this->pushBlock(null, $pos);
-        $block->type = $type;
-
-        return $block;
-    }
-
-    /**
-     * Pop scope and return last block
-     *
-     * @return \Leafo\ScssPhp\Block
-     *
-     * @throws \Exception
-     */
-    protected function popBlock()
-    {
-        $block = $this->env;
-
-        if (empty($block->parent)) {
-            $this->throwParseError('unexpected }');
-        }
-
-        $this->env = $block->parent;
-        unset($block->parent);
-
-        $comments = $block->comments;
-        if (count($comments)) {
-            $this->env->comments = $comments;
-            unset($block->comments);
-        }
-
-        return $block;
-    }
-
-    /**
-     * Peek input stream
-     *
-     * @param string  $regex
-     * @param array   $out
-     * @param integer $from
-     *
-     * @return integer
-     */
-    protected function peek($regex, &$out, $from = null)
-    {
-        if (! isset($from)) {
-            $from = $this->count;
-        }
-
-        $r = '/' . $regex . '/' . $this->patternModifiers;
-        $result = preg_match($r, $this->buffer, $out, null, $from);
-
-        return $result;
-    }
-
-    /**
-     * Seek to position in input stream (or return current position in input stream)
-     *
-     * @param integer $where
-     *
-     * @return integer
-     */
-    protected function seek($where = null)
-    {
-        if ($where === null) {
-            return $this->count;
-        }
-
-        $this->count = $where;
-
-        return true;
-    }
-
-    /**
-     * Match string looking for either ending delim, escape, or string interpolation
-     *
-     * {@internal This is a workaround for preg_match's 250K string match limit. }}
-     *
-     * @param array  $m     Matches (passed by reference)
-     * @param string $delim Delimeter
-     *
-     * @return boolean True if match; false otherwise
-     */
-    protected function matchString(&$m, $delim)
-    {
-        $token = null;
-
-        $end = strlen($this->buffer);
-
-        // look for either ending delim, escape, or string interpolation
-        foreach (['#{', '\\', $delim] as $lookahead) {
-            $pos = strpos($this->buffer, $lookahead, $this->count);
-
-            if ($pos !== false && $pos < $end) {
-                $end = $pos;
-                $token = $lookahead;
-            }
-        }
-
-        if (! isset($token)) {
-            return false;
-        }
-
-        $match = substr($this->buffer, $this->count, $end - $this->count);
-        $m = [
-            $match . $token,
-            $match,
-            $token
-        ];
-        $this->count = $end + strlen($token);
-
-        return true;
-    }
-
-    /**
-     * Try to match something on head of buffer
-     *
-     * @param string  $regex
-     * @param array   $out
-     * @param boolean $eatWhitespace
-     *
-     * @return boolean
-     */
-    protected function match($regex, &$out, $eatWhitespace = null)
-    {
-        if (! isset($eatWhitespace)) {
-            $eatWhitespace = $this->eatWhiteDefault;
-        }
-
-        $r = '/' . $regex . '/' . $this->patternModifiers;
-
-        if (preg_match($r, $this->buffer, $out, null, $this->count)) {
-            $this->count += strlen($out[0]);
-
-            if ($eatWhitespace) {
-                $this->whitespace();
-            }
-
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Match literal string
-     *
-     * @param string  $what
-     * @param boolean $eatWhitespace
-     *
-     * @return boolean
-     */
-    protected function literal($what, $eatWhitespace = null)
-    {
-        if (! isset($eatWhitespace)) {
-            $eatWhitespace = $this->eatWhiteDefault;
-        }
-
-        $len = strlen($what);
-
-        if (strcasecmp(substr($this->buffer, $this->count, $len), $what) === 0) {
-            $this->count += $len;
-
-            if ($eatWhitespace) {
-                $this->whitespace();
-            }
-
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Match some whitespace
-     *
-     * @return boolean
-     */
-    protected function whitespace()
-    {
-        $gotWhite = false;
-
-        while (preg_match(static::$whitePattern, $this->buffer, $m, null, $this->count)) {
-            if (isset($m[1]) && empty($this->commentsSeen[$this->count])) {
-                $this->appendComment([Type::T_COMMENT, $m[1]]);
-
-                $this->commentsSeen[$this->count] = true;
-            }
-
-            $this->count += strlen($m[0]);
-            $gotWhite = true;
-        }
-
-        return $gotWhite;
-    }
-
-    /**
-     * Append comment to current block
-     *
-     * @param array $comment
-     */
-    protected function appendComment($comment)
-    {
-        $comment[1] = substr(preg_replace(['/^\s+/m', '/^(.)/m'], ['', ' \1'], $comment[1]), 1);
-
-        $this->env->comments[] = $comment;
-    }
-
-    /**
-     * Append statement to current block
-     *
-     * @param array   $statement
-     * @param integer $pos
-     */
-    protected function append($statement, $pos = null)
-    {
-        if ($pos !== null) {
-            list($line, $column) = $this->getSourcePosition($pos);
-
-            $statement[static::SOURCE_LINE]   = $line;
-            $statement[static::SOURCE_COLUMN] = $column;
-            $statement[static::SOURCE_INDEX]  = $this->sourceIndex;
-        }
-
-        $this->env->children[] = $statement;
-
-        $comments = $this->env->comments;
-
-        if (count($comments)) {
-            $this->env->children = array_merge($this->env->children, $comments);
-            $this->env->comments = [];
-        }
-    }
-
-    /**
-     * Returns last child was appended
-     *
-     * @return array|null
-     */
-    protected function last()
-    {
-        $i = count($this->env->children) - 1;
-
-        if (isset($this->env->children[$i])) {
-            return $this->env->children[$i];
-        }
-    }
-
-    /**
-     * Parse media query list
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function mediaQueryList(&$out)
-    {
-        return $this->genericList($out, 'mediaQuery', ',', false);
-    }
-
-    /**
-     * Parse media query
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function mediaQuery(&$out)
-    {
-        $expressions = null;
-        $parts = [];
-
-        if (($this->literal('only') && ($only = true) || $this->literal('not') && ($not = true) || true) &&
-            $this->mixedKeyword($mediaType)
-        ) {
-            $prop = [Type::T_MEDIA_TYPE];
-
-            if (isset($only)) {
-                $prop[] = [Type::T_KEYWORD, 'only'];
-            }
-
-            if (isset($not)) {
-                $prop[] = [Type::T_KEYWORD, 'not'];
-            }
-
-            $media = [Type::T_LIST, '', []];
-
-            foreach ((array) $mediaType as $type) {
-                if (is_array($type)) {
-                    $media[2][] = $type;
-                } else {
-                    $media[2][] = [Type::T_KEYWORD, $type];
-                }
-            }
-
-            $prop[]  = $media;
-            $parts[] = $prop;
-        }
-
-        if (empty($parts) || $this->literal('and')) {
-            $this->genericList($expressions, 'mediaExpression', 'and', false);
-
-            if (is_array($expressions)) {
-                $parts = array_merge($parts, $expressions[2]);
-            }
-        }
-
-        $out = $parts;
-
-        return true;
-    }
-
-    /**
-     * Parse media expression
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function mediaExpression(&$out)
-    {
-        $s = $this->seek();
-        $value = null;
-
-        if ($this->literal('(') &&
-            $this->expression($feature) &&
-            ($this->literal(':') && $this->expression($value) || true) &&
-            $this->literal(')')
-        ) {
-            $out = [Type::T_MEDIA_EXPRESSION, $feature];
-
-            if ($value) {
-                $out[] = $value;
-            }
-
-            return true;
-        }
-
-        $this->seek($s);
-
-        return false;
-    }
-
-    /**
-     * Parse argument values
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function argValues(&$out)
-    {
-        if ($this->genericList($list, 'argValue', ',', false)) {
-            $out = $list[2];
-
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Parse argument value
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function argValue(&$out)
-    {
-        $s = $this->seek();
-
-        $keyword = null;
-
-        if (! $this->variable($keyword) || ! $this->literal(':')) {
-            $this->seek($s);
-            $keyword = null;
-        }
-
-        if ($this->genericList($value, 'expression')) {
-            $out = [$keyword, $value, false];
-            $s = $this->seek();
-
-            if ($this->literal('...')) {
-                $out[2] = true;
-            } else {
-                $this->seek($s);
-            }
-
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Parse comma separated value list
-     *
-     * @param string $out
-     *
-     * @return boolean
-     */
-    protected function valueList(&$out)
-    {
-        return $this->genericList($out, 'spaceList', ',');
-    }
-
-    /**
-     * Parse space separated value list
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function spaceList(&$out)
-    {
-        return $this->genericList($out, 'expression');
-    }
-
-    /**
-     * Parse generic list
-     *
-     * @param array    $out
-     * @param callable $parseItem
-     * @param string   $delim
-     * @param boolean  $flatten
-     *
-     * @return boolean
-     */
-    protected function genericList(&$out, $parseItem, $delim = '', $flatten = true)
-    {
-        $s = $this->seek();
-        $items = [];
-
-        while ($this->$parseItem($value)) {
-            $items[] = $value;
-
-            if ($delim) {
-                if (! $this->literal($delim)) {
-                    break;
-                }
-            }
-        }
-
-        if (count($items) === 0) {
-            $this->seek($s);
-
-            return false;
-        }
-
-        if ($flatten && count($items) === 1) {
-            $out = $items[0];
-        } else {
-            $out = [Type::T_LIST, $delim, $items];
-        }
-
-        return true;
-    }
-
-    /**
-     * Parse expression
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function expression(&$out)
-    {
-        $s = $this->seek();
-
-        if ($this->literal('(')) {
-            if ($this->literal(')')) {
-                $out = [Type::T_LIST, '', []];
-
-                return true;
-            }
-
-            if ($this->valueList($out) && $this->literal(')') && $out[0] === Type::T_LIST) {
-                return true;
-            }
-
-            $this->seek($s);
-
-            if ($this->map($out)) {
-                return true;
-            }
-
-            $this->seek($s);
-        }
-
-        if ($this->value($lhs)) {
-            $out = $this->expHelper($lhs, 0);
-
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Parse left-hand side of subexpression
-     *
-     * @param array   $lhs
-     * @param integer $minP
-     *
-     * @return array
-     */
-    protected function expHelper($lhs, $minP)
-    {
-        $operators = static::$operatorPattern;
-
-        $ss = $this->seek();
-        $whiteBefore = isset($this->buffer[$this->count - 1]) &&
-            ctype_space($this->buffer[$this->count - 1]);
-
-        while ($this->match($operators, $m, false) && static::$precedence[$m[1]] >= $minP) {
-            $whiteAfter = isset($this->buffer[$this->count]) &&
-                ctype_space($this->buffer[$this->count]);
-            $varAfter = isset($this->buffer[$this->count]) &&
-                $this->buffer[$this->count] === '$';
-
-            $this->whitespace();
-
-            $op = $m[1];
-
-            // don't turn negative numbers into expressions
-            if ($op === '-' && $whiteBefore && ! $whiteAfter && ! $varAfter) {
-                break;
-            }
-
-            if (! $this->value($rhs)) {
-                break;
-            }
-
-            // peek and see if rhs belongs to next operator
-            if ($this->peek($operators, $next) && static::$precedence[$next[1]] > static::$precedence[$op]) {
-                $rhs = $this->expHelper($rhs, static::$precedence[$next[1]]);
-            }
-
-            $lhs = [Type::T_EXPRESSION, $op, $lhs, $rhs, $this->inParens, $whiteBefore, $whiteAfter];
-            $ss = $this->seek();
-            $whiteBefore = isset($this->buffer[$this->count - 1]) &&
-                ctype_space($this->buffer[$this->count - 1]);
-        }
-
-        $this->seek($ss);
-
-        return $lhs;
-    }
-
-    /**
-     * Parse value
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function value(&$out)
-    {
-        $s = $this->seek();
-
-        if ($this->literal('not', false) && $this->whitespace() && $this->value($inner)) {
-            $out = [Type::T_UNARY, 'not', $inner, $this->inParens];
-
-            return true;
-        }
-
-        $this->seek($s);
-
-        if ($this->literal('not', false) && $this->parenValue($inner)) {
-            $out = [Type::T_UNARY, 'not', $inner, $this->inParens];
-
-            return true;
-        }
-
-        $this->seek($s);
-
-        if ($this->literal('+') && $this->value($inner)) {
-            $out = [Type::T_UNARY, '+', $inner, $this->inParens];
-
-            return true;
-        }
-
-        $this->seek($s);
-
-        // negation
-        if ($this->literal('-', false) &&
-            ($this->variable($inner) ||
-            $this->unit($inner) ||
-            $this->parenValue($inner))
-        ) {
-            $out = [Type::T_UNARY, '-', $inner, $this->inParens];
-
-            return true;
-        }
-
-        $this->seek($s);
-
-        if ($this->parenValue($out) ||
-            $this->interpolation($out) ||
-            $this->variable($out) ||
-            $this->color($out) ||
-            $this->unit($out) ||
-            $this->string($out) ||
-            $this->func($out) ||
-            $this->progid($out)
-        ) {
-            return true;
-        }
-
-        if ($this->keyword($keyword)) {
-            if ($keyword === 'null') {
-                $out = [Type::T_NULL];
-            } else {
-                $out = [Type::T_KEYWORD, $keyword];
-            }
-
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Parse parenthesized value
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function parenValue(&$out)
-    {
-        $s = $this->seek();
-
-        $inParens = $this->inParens;
-
-        if ($this->literal('(')) {
-            if ($this->literal(')')) {
-                $out = [Type::T_LIST, '', []];
-
-                return true;
-            }
-
-            $this->inParens = true;
-
-            if ($this->expression($exp) && $this->literal(')')) {
-                $out = $exp;
-                $this->inParens = $inParens;
-
-                return true;
-            }
-        }
-
-        $this->inParens = $inParens;
-        $this->seek($s);
-
-        return false;
-    }
-
-    /**
-     * Parse "progid:"
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function progid(&$out)
-    {
-        $s = $this->seek();
-
-        if ($this->literal('progid:', false) &&
-            $this->openString('(', $fn) &&
-            $this->literal('(')
-        ) {
-            $this->openString(')', $args, '(');
-
-            if ($this->literal(')')) {
-                $out = [Type::T_STRING, '', [
-                    'progid:', $fn, '(', $args, ')'
-                ]];
-
-                return true;
-            }
-        }
-
-        $this->seek($s);
-
-        return false;
-    }
-
-    /**
-     * Parse function call
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function func(&$func)
-    {
-        $s = $this->seek();
-
-        if ($this->keyword($name, false) &&
-            $this->literal('(')
-        ) {
-            if ($name === 'alpha' && $this->argumentList($args)) {
-                $func = [Type::T_FUNCTION, $name, [Type::T_STRING, '', $args]];
-
-                return true;
-            }
-
-            if ($name !== 'expression' && ! preg_match('/^(-[a-z]+-)?calc$/', $name)) {
-                $ss = $this->seek();
-
-                if ($this->argValues($args) && $this->literal(')')) {
-                    $func = [Type::T_FUNCTION_CALL, $name, $args];
-
-                    return true;
-                }
-
-                $this->seek($ss);
-            }
-
-            if (($this->openString(')', $str, '(') || true) &&
-                $this->literal(')')
-            ) {
-                $args = [];
-
-                if (! empty($str)) {
-                    $args[] = [null, [Type::T_STRING, '', [$str]]];
-                }
-
-                $func = [Type::T_FUNCTION_CALL, $name, $args];
-
-                return true;
-            }
-        }
-
-        $this->seek($s);
-
-        return false;
-    }
-
-    /**
-     * Parse function call argument list
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function argumentList(&$out)
-    {
-        $s = $this->seek();
-        $this->literal('(');
-
-        $args = [];
-
-        while ($this->keyword($var)) {
-            if ($this->literal('=') && $this->expression($exp)) {
-                $args[] = [Type::T_STRING, '', [$var . '=']];
-                $arg = $exp;
-            } else {
-                break;
-            }
-
-            $args[] = $arg;
-
-            if (! $this->literal(',')) {
-                break;
-            }
-
-            $args[] = [Type::T_STRING, '', [', ']];
-        }
-
-        if (! $this->literal(')') || ! count($args)) {
-            $this->seek($s);
-
-            return false;
-        }
-
-        $out = $args;
-
-        return true;
-    }
-
-    /**
-     * Parse mixin/function definition  argument list
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function argumentDef(&$out)
-    {
-        $s = $this->seek();
-        $this->literal('(');
-
-        $args = [];
-
-        while ($this->variable($var)) {
-            $arg = [$var[1], null, false];
-
-            $ss = $this->seek();
-
-            if ($this->literal(':') && $this->genericList($defaultVal, 'expression')) {
-                $arg[1] = $defaultVal;
-            } else {
-                $this->seek($ss);
-            }
-
-            $ss = $this->seek();
-
-            if ($this->literal('...')) {
-                $sss = $this->seek();
-
-                if (! $this->literal(')')) {
-                    $this->throwParseError('... has to be after the final argument');
-                }
-
-                $arg[2] = true;
-                $this->seek($sss);
-            } else {
-                $this->seek($ss);
-            }
-
-            $args[] = $arg;
-
-            if (! $this->literal(',')) {
-                break;
-            }
-        }
-
-        if (! $this->literal(')')) {
-            $this->seek($s);
-
-            return false;
-        }
-
-        $out = $args;
-
-        return true;
-    }
-
-    /**
-     * Parse map
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function map(&$out)
-    {
-        $s = $this->seek();
-
-        if (! $this->literal('(')) {
-            return false;
-        }
-
-        $keys = [];
-        $values = [];
-
-        while ($this->genericList($key, 'expression') && $this->literal(':') &&
-            $this->genericList($value, 'expression')
-        ) {
-            $keys[] = $key;
-            $values[] = $value;
-
-            if (! $this->literal(',')) {
-                break;
-            }
-        }
-
-        if (! count($keys) || ! $this->literal(')')) {
-            $this->seek($s);
-
-            return false;
-        }
-
-        $out = [Type::T_MAP, $keys, $values];
-
-        return true;
-    }
-
-    /**
-     * Parse color
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function color(&$out)
-    {
-        $color = [Type::T_COLOR];
-
-        if ($this->match('(#([0-9a-f]{6})|#([0-9a-f]{3}))', $m)) {
-            if (isset($m[3])) {
-                $num = hexdec($m[3]);
-
-                foreach ([3, 2, 1] as $i) {
-                    $t = $num & 0xf;
-                    $color[$i] = $t << 4 | $t;
-                    $num >>= 4;
-                }
-            } else {
-                $num = hexdec($m[2]);
-
-                foreach ([3, 2, 1] as $i) {
-                    $color[$i] = $num & 0xff;
-                    $num >>= 8;
-                }
-            }
-
-            $out = $color;
-
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Parse number with unit
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function unit(&$unit)
-    {
-        if ($this->match('([0-9]*(\.)?[0-9]+)([%a-zA-Z]+)?', $m)) {
-            $unit = new Node\Number($m[1], empty($m[3]) ? '' : $m[3]);
-
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Parse string
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function string(&$out)
-    {
-        $s = $this->seek();
-
-        if ($this->literal('"', false)) {
-            $delim = '"';
-        } elseif ($this->literal("'", false)) {
-            $delim = "'";
-        } else {
-            return false;
-        }
-
-        $content = [];
-        $oldWhite = $this->eatWhiteDefault;
-        $this->eatWhiteDefault = false;
-        $hasInterpolation = false;
-
-        while ($this->matchString($m, $delim)) {
-            if ($m[1] !== '') {
-                $content[] = $m[1];
-            }
-
-            if ($m[2] === '#{') {
-                $this->count -= strlen($m[2]);
-
-                if ($this->interpolation($inter, false)) {
-                    $content[] = $inter;
-                    $hasInterpolation = true;
-                } else {
-                    $this->count += strlen($m[2]);
-                    $content[] = '#{'; // ignore it
-                }
-            } elseif ($m[2] === '\\') {
-                if ($this->literal('"', false)) {
-                    $content[] = $m[2] . '"';
-                } elseif ($this->literal("'", false)) {
-                    $content[] = $m[2] . "'";
-                } else {
-                    $content[] = $m[2];
-                }
-            } else {
-                $this->count -= strlen($delim);
-                break; // delim
-            }
-        }
-
-        $this->eatWhiteDefault = $oldWhite;
-
-        if ($this->literal($delim)) {
-            if ($hasInterpolation) {
-                $delim = '"';
-
-                foreach ($content as &$string) {
-                    if ($string === "\\'") {
-                        $string = "'";
-                    } elseif ($string === '\\"') {
-                        $string = '"';
-                    }
-                }
-            }
-
-            $out = [Type::T_STRING, $delim, $content];
-
-            return true;
-        }
-
-        $this->seek($s);
-
-        return false;
-    }
-
-    /**
-     * Parse keyword or interpolation
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function mixedKeyword(&$out)
-    {
-        $parts = [];
-
-        $oldWhite = $this->eatWhiteDefault;
-        $this->eatWhiteDefault = false;
-
-        for (;;) {
-            if ($this->keyword($key)) {
-                $parts[] = $key;
-                continue;
-            }
-
-            if ($this->interpolation($inter)) {
-                $parts[] = $inter;
-                continue;
-            }
-
-            break;
-        }
-
-        $this->eatWhiteDefault = $oldWhite;
-
-        if (count($parts) === 0) {
-            return false;
-        }
-
-        if ($this->eatWhiteDefault) {
-            $this->whitespace();
-        }
-
-        $out = $parts;
-
-        return true;
-    }
-
-    /**
-     * Parse an unbounded string stopped by $end
-     *
-     * @param string $end
-     * @param array  $out
-     * @param string $nestingOpen
-     *
-     * @return boolean
-     */
-    protected function openString($end, &$out, $nestingOpen = null)
-    {
-        $oldWhite = $this->eatWhiteDefault;
-        $this->eatWhiteDefault = false;
-
-        $patt = '(.*?)([\'"]|#\{|' . $this->pregQuote($end) . '|' . static::$commentPattern . ')';
-
-        $nestingLevel = 0;
-
-        $content = [];
-
-        while ($this->match($patt, $m, false)) {
-            if (isset($m[1]) && $m[1] !== '') {
-                $content[] = $m[1];
-
-                if ($nestingOpen) {
-                    $nestingLevel += substr_count($m[1], $nestingOpen);
-                }
-            }
-
-            $tok = $m[2];
-
-            $this->count-= strlen($tok);
-
-            if ($tok === $end && ! $nestingLevel--) {
-                break;
-            }
-
-            if (($tok === "'" || $tok === '"') && $this->string($str)) {
-                $content[] = $str;
-                continue;
-            }
-
-            if ($tok === '#{' && $this->interpolation($inter)) {
-                $content[] = $inter;
-                continue;
-            }
-
-            $content[] = $tok;
-            $this->count+= strlen($tok);
-        }
-
-        $this->eatWhiteDefault = $oldWhite;
-
-        if (count($content) === 0) {
-            return false;
-        }
-
-        // trim the end
-        if (is_string(end($content))) {
-            $content[count($content) - 1] = rtrim(end($content));
-        }
-
-        $out = [Type::T_STRING, '', $content];
-
-        return true;
-    }
-
-    /**
-     * Parser interpolation
-     *
-     * @param array   $out
-     * @param boolean $lookWhite save information about whitespace before and after
-     *
-     * @return boolean
-     */
-    protected function interpolation(&$out, $lookWhite = true)
-    {
-        $oldWhite = $this->eatWhiteDefault;
-        $this->eatWhiteDefault = true;
-
-        $s = $this->seek();
-
-        if ($this->literal('#{') && $this->valueList($value) && $this->literal('}', false)) {
-            if ($lookWhite) {
-                $left = preg_match('/\s/', $this->buffer[$s - 1]) ? ' ' : '';
-                $right = preg_match('/\s/', $this->buffer[$this->count]) ? ' ': '';
-            } else {
-                $left = $right = false;
-            }
-
-            $out = [Type::T_INTERPOLATE, $value, $left, $right];
-            $this->eatWhiteDefault = $oldWhite;
-
-            if ($this->eatWhiteDefault) {
-                $this->whitespace();
-            }
-
-            return true;
-        }
-
-        $this->seek($s);
-        $this->eatWhiteDefault = $oldWhite;
-
-        return false;
-    }
-
-    /**
-     * Parse property name (as an array of parts or a string)
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function propertyName(&$out)
-    {
-        $parts = [];
-
-        $oldWhite = $this->eatWhiteDefault;
-        $this->eatWhiteDefault = false;
-
-        for (;;) {
-            if ($this->interpolation($inter)) {
-                $parts[] = $inter;
-                continue;
-            }
-
-            if ($this->keyword($text)) {
-                $parts[] = $text;
-                continue;
-            }
-
-            if (count($parts) === 0 && $this->match('[:.#]', $m, false)) {
-                // css hacks
-                $parts[] = $m[0];
-                continue;
-            }
-
-            break;
-        }
-
-        $this->eatWhiteDefault = $oldWhite;
-
-        if (count($parts) === 0) {
-            return false;
-        }
-
-        // match comment hack
-        if (preg_match(
-            static::$whitePattern,
-            $this->buffer,
-            $m,
-            null,
-            $this->count
-        )) {
-            if (! empty($m[0])) {
-                $parts[] = $m[0];
-                $this->count += strlen($m[0]);
-            }
-        }
-
-        $this->whitespace(); // get any extra whitespace
-
-        $out = [Type::T_STRING, '', $parts];
-
-        return true;
-    }
-
-    /**
-     * Parse comma separated selector list
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function selectors(&$out)
-    {
-        $s = $this->seek();
-        $selectors = [];
-
-        while ($this->selector($sel)) {
-            $selectors[] = $sel;
-
-            if (! $this->literal(',')) {
-                break;
-            }
-
-            while ($this->literal(',')) {
-                ; // ignore extra
-            }
-        }
-
-        if (count($selectors) === 0) {
-            $this->seek($s);
-
-            return false;
-        }
-
-        $out = $selectors;
-
-        return true;
-    }
-
-    /**
-     * Parse whitespace separated selector list
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function selector(&$out)
-    {
-        $selector = [];
-
-        for (;;) {
-            if ($this->match('[>+~]+', $m)) {
-                $selector[] = [$m[0]];
-                continue;
-            }
-
-            if ($this->selectorSingle($part)) {
-                $selector[] = $part;
-                $this->match('\s+', $m);
-                continue;
-            }
-
-            if ($this->match('\/[^\/]+\/', $m)) {
-                $selector[] = [$m[0]];
-                continue;
-            }
-
-            break;
-        }
-
-        if (count($selector) === 0) {
-            return false;
-        }
-
-        $out = $selector;
-        return true;
-    }
-
-    /**
-     * Parse the parts that make up a selector
-     *
-     * {@internal
-     *     div[yes=no]#something.hello.world:nth-child(-2n+1)%placeholder
-     * }}
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function selectorSingle(&$out)
-    {
-        $oldWhite = $this->eatWhiteDefault;
-        $this->eatWhiteDefault = false;
-
-        $parts = [];
-
-        if ($this->literal('*', false)) {
-            $parts[] = '*';
-        }
-
-        for (;;) {
-            // see if we can stop early
-            if ($this->match('\s*[{,]', $m)) {
-                $this->count--;
-                break;
-            }
-
-            $s = $this->seek();
-
-            // self
-            if ($this->literal('&', false)) {
-                $parts[] = Compiler::$selfSelector;
-                continue;
-            }
-
-            if ($this->literal('.', false)) {
-                $parts[] = '.';
-                continue;
-            }
-
-            if ($this->literal('|', false)) {
-                $parts[] = '|';
-                continue;
-            }
-
-            if ($this->match('\\\\\S', $m)) {
-                $parts[] = $m[0];
-                continue;
-            }
-
-            // for keyframes
-            if ($this->unit($unit)) {
-                $parts[] = $unit;
-                continue;
-            }
-
-            if ($this->keyword($name)) {
-                $parts[] = $name;
-                continue;
-            }
-
-            if ($this->interpolation($inter)) {
-                $parts[] = $inter;
-                continue;
-            }
-
-            if ($this->literal('%', false) && $this->placeholder($placeholder)) {
-                $parts[] = '%';
-                $parts[] = $placeholder;
-                continue;
-            }
-
-            if ($this->literal('#', false)) {
-                $parts[] = '#';
-                continue;
-            }
-
-            // a pseudo selector
-            if ($this->match('::?', $m) && $this->mixedKeyword($nameParts)) {
-                $parts[] = $m[0];
-
-                foreach ($nameParts as $sub) {
-                    $parts[] = $sub;
-                }
-
-                $ss = $this->seek();
-
-                if ($this->literal('(') &&
-                    ($this->openString(')', $str, '(') || true) &&
-                    $this->literal(')')
-                ) {
-                    $parts[] = '(';
-
-                    if (! empty($str)) {
-                        $parts[] = $str;
-                    }
-
-                    $parts[] = ')';
-                } else {
-                    $this->seek($ss);
-                }
-
-                continue;
-            }
-
-            $this->seek($s);
-
-            // attribute selector
-            if ($this->literal('[') &&
-               ($this->openString(']', $str, '[') || true) &&
-               $this->literal(']')
-            ) {
-                $parts[] = '[';
-
-                if (! empty($str)) {
-                    $parts[] = $str;
-                }
-
-                $parts[] = ']';
-
-                continue;
-            }
-
-            $this->seek($s);
-
-            break;
-        }
-
-        $this->eatWhiteDefault = $oldWhite;
-
-        if (count($parts) === 0) {
-            return false;
-        }
-
-        $out = $parts;
-
-        return true;
-    }
-
-    /**
-     * Parse a variable
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function variable(&$out)
-    {
-        $s = $this->seek();
-
-        if ($this->literal('$', false) && $this->keyword($name)) {
-            $out = [Type::T_VARIABLE, $name];
-
-            return true;
-        }
-
-        $this->seek($s);
-
-        return false;
-    }
-
-    /**
-     * Parse a keyword
-     *
-     * @param string  $word
-     * @param boolean $eatWhitespace
-     *
-     * @return boolean
-     */
-    protected function keyword(&$word, $eatWhitespace = null)
-    {
-        if ($this->match(
-            $this->utf8
-                ? '(([\pL\w_\-\*!"\']|[\\\\].)([\pL\w\-_"\']|[\\\\].)*)'
-                : '(([\w_\-\*!"\']|[\\\\].)([\w\-_"\']|[\\\\].)*)',
-            $m,
-            $eatWhitespace
-        )) {
-            $word = $m[1];
-
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Parse a placeholder
-     *
-     * @param string $placeholder
-     *
-     * @return boolean
-     */
-    protected function placeholder(&$placeholder)
-    {
-        if ($this->match(
-            $this->utf8
-                ? '([\pL\w\-_]+|#[{][$][\pL\w\-_]+[}])'
-                : '([\w\-_]+|#[{][$][\w\-_]+[}])',
-            $m
-        )) {
-            $placeholder = $m[1];
-
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Parse a url
-     *
-     * @param array $out
-     *
-     * @return boolean
-     */
-    protected function url(&$out)
-    {
-        if ($this->match('(url\(\s*(["\']?)([^)]+)\2\s*\))', $m)) {
-            $out = [Type::T_STRING, '', ['url(' . $m[2] . $m[3] . $m[2] . ')']];
-
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Consume an end of statement delimiter
-     *
-     * @return boolean
-     */
-    protected function end()
-    {
-        if ($this->literal(';')) {
-            return true;
-        }
-
-        if ($this->count === strlen($this->buffer) || $this->buffer[$this->count] === '}') {
-            // if there is end of file or a closing block next then we don't need a ;
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Strip assignment flag from the list
-     *
-     * @param array $value
-     *
-     * @return array
-     */
-    protected function stripAssignmentFlags(&$value)
-    {
-        $flags = [];
-
-        for ($token = &$value; $token[0] === Type::T_LIST && ($s = count($token[2])); $token = &$lastNode) {
-            $lastNode = &$token[2][$s - 1];
-
-            while ($lastNode[0] === Type::T_KEYWORD && in_array($lastNode[1], ['!default', '!global'])) {
-                array_pop($token[2]);
-
-                $node = end($token[2]);
-
-                $token = $this->flattenList($token);
-
-                $flags[] = $lastNode[1];
-
-                $lastNode = $node;
-            }
-        }
-
-        return $flags;
-    }
-
-    /**
-     * Strip optional flag from selector list
-     *
-     * @param array $selectors
-     *
-     * @return string
-     */
-    protected function stripOptionalFlag(&$selectors)
-    {
-        $optional = false;
-
-        $selector = end($selectors);
-        $part = end($selector);
-
-        if ($part === ['!optional']) {
-            array_pop($selectors[count($selectors) - 1]);
-
-            $optional = true;
-        }
-
-        return $optional;
-    }
-
-    /**
-     * Turn list of length 1 into value type
-     *
-     * @param array $value
-     *
-     * @return array
-     */
-    protected function flattenList($value)
-    {
-        if ($value[0] === Type::T_LIST && count($value[2]) === 1) {
-            return $this->flattenList($value[2][0]);
-        }
-
-        return $value;
-    }
-
-    /**
-     * @deprecated
-     *
-     * {@internal
-     *     advance counter to next occurrence of $what
-     *     $until - don't include $what in advance
-     *     $allowNewline, if string, will be used as valid char set
-     * }}
-     */
-    protected function to($what, &$out, $until = false, $allowNewline = false)
-    {
-        if (is_string($allowNewline)) {
-            $validChars = $allowNewline;
-        } else {
-            $validChars = $allowNewline ? '.' : "[^\n]";
-        }
-
-        if (! $this->match('(' . $validChars . '*?)' . $this->pregQuote($what), $m, ! $until)) {
-            return false;
-        }
-
-        if ($until) {
-            $this->count -= strlen($what); // give back $what
-        }
-
-        $out = $m[1];
-
-        return true;
-    }
-
-    /**
-     * @deprecated
-     */
-    protected function show()
-    {
-        if ($this->peek("(.*?)(\n|$)", $m, $this->count)) {
-            return $m[1];
-        }
-
-        return '';
-    }
-
-    /**
-     * Quote regular expression
-     *
-     * @param string $what
-     *
-     * @return string
-     */
-    private function pregQuote($what)
-    {
-        return preg_quote($what, '/');
-    }
-
-    /**
-     * Extract line numbers from buffer
-     *
-     * @param string $buffer
-     */
-    private function extractLineNumbers($buffer)
-    {
-        $this->sourcePositions = [0 => 0];
-        $prev = 0;
-
-        while (($pos = strpos($buffer, "\n", $prev)) !== false) {
-            $this->sourcePositions[] = $pos;
-            $prev = $pos + 1;
-        }
-
-        $this->sourcePositions[] = strlen($buffer);
-
-        if (substr($buffer, -1) !== "\n") {
-            $this->sourcePositions[] = strlen($buffer) + 1;
-        }
-    }
-
-    /**
-     * Get source line number and column (given character position in the buffer)
-     *
-     * @param integer $pos
-     *
-     * @return integer
-     */
-    private function getSourcePosition($pos)
-    {
-        $low = 0;
-        $high = count($this->sourcePositions);
-
-        while ($low < $high) {
-            $mid = (int) (($high + $low) / 2);
-
-            if ($pos < $this->sourcePositions[$mid]) {
-                $high = $mid - 1;
-                continue;
-            }
-
-            if ($pos >= $this->sourcePositions[$mid + 1]) {
-                $low = $mid + 1;
-                continue;
-            }
-
-            return [$mid + 1, $pos - $this->sourcePositions[$mid]];
-        }
-
-        return [$low + 1, $pos - $this->sourcePositions[$low]];
-    }
-
-    /**
-     * Save internal encoding
-     */
-    private function saveEncoding()
-    {
-        if (version_compare(PHP_VERSION, '7.2.0') >= 0) {
-            return;
-        }
-
-        $iniDirective = 'mbstring' . '.func_overload'; // deprecated in PHP 7.2
-
-        if (ini_get($iniDirective) & 2) {
-            $this->encoding = mb_internal_encoding();
-
-            mb_internal_encoding('iso-8859-1');
-        }
-    }
-
-    /**
-     * Restore internal encoding
-     */
-    private function restoreEncoding()
-    {
-        if ($this->encoding) {
-            mb_internal_encoding($this->encoding);
-        }
-    }
-}
diff --git a/inc/scssphp--old/src/SourceMap/Base64VLQEncoder.php b/inc/scssphp--old/src/SourceMap/Base64VLQEncoder.php
deleted file mode 100644
index 1189ce0..0000000
--- a/inc/scssphp--old/src/SourceMap/Base64VLQEncoder.php
+++ /dev/null
@@ -1,217 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp\SourceMap;
-
-/**
- * Base64 VLQ Encoder
- *
- * {@internal Derivative of oyejorge/less.php's lib/SourceMap/Base64VLQ.php, relicensed with permission. }}
- *
- * @author Josh Schmidt <oyejorge@gmail.com>
- * @author Nicolas FRANÇOIS <nicolas.francois@frog-labs.com>
- */
-class Base64VLQEncoder
-{
-    /**
-     * Shift
-     *
-     * @var integer
-     */
-    private $shift = 5;
-
-    /**
-     * Mask
-     *
-     * @var integer
-     */
-    private $mask = 0x1F; // == (1 << shift) == 0b00011111
-
-    /**
-     * Continuation bit
-     *
-     * @var integer
-     */
-    private $continuationBit = 0x20; // == (mask - 1 ) == 0b00100000
-
-    /**
-     * Char to integer map
-     *
-     * @var array
-     */
-    private $charToIntMap = array(
-        'A' => 0,  'B' => 1,  'C' => 2,  'D' => 3,  'E' => 4,  'F' => 5,  'G' => 6,  'H' => 7,
-        'I' => 8,  'J' => 9,  'K' => 10, 'L' => 11, 'M' => 12, 'N' => 13, 'O' => 14, 'P' => 15,
-        'Q' => 16, 'R' => 17, 'S' => 18, 'T' => 19, 'U' => 20, 'V' => 21, 'W' => 22, 'X' => 23,
-        'Y' => 24, 'Z' => 25, 'a' => 26, 'b' => 27, 'c' => 28, 'd' => 29, 'e' => 30, 'f' => 31,
-        'g' => 32, 'h' => 33, 'i' => 34, 'j' => 35, 'k' => 36, 'l' => 37, 'm' => 38, 'n' => 39,
-        'o' => 40, 'p' => 41, 'q' => 42, 'r' => 43, 's' => 44, 't' => 45, 'u' => 46, 'v' => 47,
-        'w' => 48, 'x' => 49, 'y' => 50, 'z' => 51,   0 => 52,   1 => 53,   2 => 54,   3 => 55,
-          4 => 56,   5 => 57,   6 => 58,   7 => 59,   8 => 60,   9 => 61, '+' => 62, '/' => 63,
-    );
-
-    /**
-     * Integer to char map
-     *
-     * @var array
-     */
-    private $intToCharMap = array(
-         0 => 'A',  1 => 'B',  2 => 'C',  3 => 'D',  4 => 'E',  5 => 'F',  6 => 'G',  7 => 'H',
-         8 => 'I',  9 => 'J', 10 => 'K', 11 => 'L', 12 => 'M', 13 => 'N', 14 => 'O', 15 => 'P',
-        16 => 'Q', 17 => 'R', 18 => 'S', 19 => 'T', 20 => 'U', 21 => 'V', 22 => 'W', 23 => 'X',
-        24 => 'Y', 25 => 'Z', 26 => 'a', 27 => 'b', 28 => 'c', 29 => 'd', 30 => 'e', 31 => 'f',
-        32 => 'g', 33 => 'h', 34 => 'i', 35 => 'j', 36 => 'k', 37 => 'l', 38 => 'm', 39 => 'n',
-        40 => 'o', 41 => 'p', 42 => 'q', 43 => 'r', 44 => 's', 45 => 't', 46 => 'u', 47 => 'v',
-        48 => 'w', 49 => 'x', 50 => 'y', 51 => 'z', 52 => '0', 53 => '1', 54 => '2', 55 => '3',
-        56 => '4', 57 => '5', 58 => '6', 59 => '7', 60 => '8', 61 => '9', 62 => '+', 63 => '/',
-    );
-
-    /**
-     * Constructor
-     */
-    public function __construct()
-    {
-        // I leave it here for future reference
-        // foreach (str_split('ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/') as $i => $char)
-        // {
-        //     $this->charToIntMap[$char] = $i;
-        //     $this->intToCharMap[$i] = $char;
-        // }
-    }
-
-    /**
-     * Convert from a two-complement value to a value where the sign bit is
-     * is placed in the least significant bit. For example, as decimals:
-     *   1 becomes 2 (10 binary), -1 becomes 3 (11 binary)
-     *   2 becomes 4 (100 binary), -2 becomes 5 (101 binary)
-     * We generate the value for 32 bit machines, hence -2147483648 becomes 1, not 4294967297,
-     * even on a 64 bit machine.
-     *
-     * @param string $aValue
-     */
-    public function toVLQSigned($aValue)
-    {
-        return 0xffffffff & ($aValue < 0 ? ((-$aValue) << 1) + 1 : ($aValue << 1) + 0);
-    }
-
-    /**
-     * Convert to a two-complement value from a value where the sign bit is
-     * is placed in the least significant bit. For example, as decimals:
-     *   2 (10 binary) becomes 1, 3 (11 binary) becomes -1
-     *   4 (100 binary) becomes 2, 5 (101 binary) becomes -2
-     * We assume that the value was generated with a 32 bit machine in mind.
-     * Hence
-     *   1 becomes -2147483648
-     * even on a 64 bit machine.
-     *
-     * @param integer $aValue
-     */
-    public function fromVLQSigned($aValue)
-    {
-        return $aValue & 1 ? $this->zeroFill(~$aValue + 2, 1) | (-1 - 0x7fffffff) : $this->zeroFill($aValue, 1);
-    }
-
-    /**
-     * Return the base 64 VLQ encoded value.
-     *
-     * @param string $aValue The value to encode
-     *
-     * @return string The encoded value
-     */
-    public function encode($aValue)
-    {
-        $encoded = '';
-        $vlq = $this->toVLQSigned($aValue);
-
-        do {
-            $digit = $vlq & $this->mask;
-            $vlq = $this->zeroFill($vlq, $this->shift);
-
-            if ($vlq > 0) {
-                $digit |= $this->continuationBit;
-            }
-
-            $encoded .= $this->base64Encode($digit);
-        } while ($vlq > 0);
-
-        return $encoded;
-    }
-
-    /**
-     * Return the value decoded from base 64 VLQ.
-     *
-     * @param string $encoded The encoded value to decode
-     *
-     * @return integer The decoded value
-     */
-    public function decode($encoded)
-    {
-        $vlq = 0;
-        $i = 0;
-
-        do {
-            $digit = $this->base64Decode($encoded[$i]);
-            $vlq |= ($digit & $this->mask) << ($i * $this->shift);
-            $i++;
-        } while ($digit & $this->continuationBit);
-
-        return $this->fromVLQSigned($vlq);
-    }
-
-    /**
-     * Right shift with zero fill.
-     *
-     * @param integer $a number to shift
-     * @param integer $b number of bits to shift
-     *
-     * @return integer
-     */
-    public function zeroFill($a, $b)
-    {
-        return ($a >= 0) ? ($a >> $b) : ($a >> $b) & (PHP_INT_MAX >> ($b - 1));
-    }
-
-    /**
-     * Encode single 6-bit digit as base64.
-     *
-     * @param integer $number
-     *
-     * @return string
-     *
-     * @throws \Exception If the number is invalid
-     */
-    public function base64Encode($number)
-    {
-        if ($number < 0 || $number > 63) {
-            throw new \Exception(sprintf('Invalid number "%s" given. Must be between 0 and 63.', $number));
-        }
-
-        return $this->intToCharMap[$number];
-    }
-
-    /**
-     * Decode single 6-bit digit from base64
-     *
-     * @param string $char
-     *
-     * @return integer
-     *
-     * @throws \Exception If the number is invalid
-     */
-    public function base64Decode($char)
-    {
-        if (! array_key_exists($char, $this->charToIntMap)) {
-            throw new \Exception(sprintf('Invalid base 64 digit "%s" given.', $char));
-        }
-
-        return $this->charToIntMap[$char];
-    }
-}
diff --git a/inc/scssphp--old/src/SourceMap/SourceMapGenerator.php b/inc/scssphp--old/src/SourceMap/SourceMapGenerator.php
deleted file mode 100644
index 70b47cd..0000000
--- a/inc/scssphp--old/src/SourceMap/SourceMapGenerator.php
+++ /dev/null
@@ -1,337 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp\SourceMap;
-
-use Leafo\ScssPhp\Exception\CompilerException;
-
-/**
- * Source Map Generator
- *
- * {@internal Derivative of oyejorge/less.php's lib/SourceMap/Generator.php, relicensed with permission. }}
- *
- * @author Josh Schmidt <oyejorge@gmail.com>
- * @author Nicolas FRANÇOIS <nicolas.francois@frog-labs.com>
- */
-class SourceMapGenerator
-{
-    /**
-     * What version of source map does the generator generate?
-     */
-    const VERSION = 3;
-
-    /**
-     * Array of default options
-     *
-     * @var array
-     */
-    protected $defaultOptions = array(
-        // an optional source root, useful for relocating source files
-        // on a server or removing repeated values in the 'sources' entry.
-        // This value is prepended to the individual entries in the 'source' field.
-        'sourceRoot' => '',
-
-        // an optional name of the generated code that this source map is associated with.
-        'sourceMapFilename' => null,
-
-        // url of the map
-        'sourceMapURL' => null,
-
-        // absolute path to a file to write the map to
-        'sourceMapWriteTo' => null,
-
-        // output source contents?
-        'outputSourceFiles' => false,
-
-        // base path for filename normalization
-        'sourceMapRootpath' => '',
-
-        // base path for filename normalization
-        'sourceMapBasepath' => ''
-    );
-
-    /**
-     * The base64 VLQ encoder
-     *
-     * @var \Leafo\ScssPhp\SourceMap\Base64VLQEncoder
-     */
-    protected $encoder;
-
-    /**
-     * Array of mappings
-     *
-     * @var array
-     */
-    protected $mappings = array();
-
-    /**
-     * Array of contents map
-     *
-     * @var array
-     */
-    protected $contentsMap = array();
-
-    /**
-     * File to content map
-     *
-     * @var array
-     */
-    protected $sources = array();
-    protected $source_keys = array();
-
-    /**
-     * @var array
-     */
-    private $options;
-
-    public function __construct(array $options = [])
-    {
-        $this->options = array_merge($this->defaultOptions, $options);
-        $this->encoder = new Base64VLQEncoder();
-    }
-
-    /**
-     * Adds a mapping
-     *
-     * @param integer $generatedLine   The line number in generated file
-     * @param integer $generatedColumn The column number in generated file
-     * @param integer $originalLine    The line number in original file
-     * @param integer $originalColumn  The column number in original file
-     * @param string  $sourceFile      The original source file
-     */
-    public function addMapping($generatedLine, $generatedColumn, $originalLine, $originalColumn, $sourceFile)
-    {
-        $this->mappings[] = array(
-            'generated_line' => $generatedLine,
-            'generated_column' => $generatedColumn,
-            'original_line' => $originalLine,
-            'original_column' => $originalColumn,
-            'source_file' => $sourceFile
-        );
-
-        $this->sources[$sourceFile] = $sourceFile;
-    }
-
-    /**
-     * Saves the source map to a file
-     *
-     * @param string $file    The absolute path to a file
-     * @param string $content The content to write
-     *
-     * @throws \Leafo\ScssPhp\Exception\CompilerException If the file could not be saved
-     */
-    public function saveMap($content)
-    {
-        $file = $this->options['sourceMapWriteTo'];
-        $dir  = dirname($file);
-
-        // directory does not exist
-        if (! is_dir($dir)) {
-            // FIXME: create the dir automatically?
-            throw new CompilerException(sprintf('The directory "%s" does not exist. Cannot save the source map.', $dir));
-        }
-
-        // FIXME: proper saving, with dir write check!
-        if (file_put_contents($file, $content) === false) {
-            throw new CompilerException(sprintf('Cannot save the source map to "%s"', $file));
-        }
-
-        return $this->options['sourceMapURL'];
-    }
-
-    /**
-     * Generates the JSON source map
-     *
-     * @return string
-     *
-     * @see https://docs.google.com/document/d/1U1RGAehQwRypUTovF1KRlpiOFze0b-_2gc6fAH0KY0k/edit#
-     */
-    public function generateJson()
-    {
-        $sourceMap = array();
-        $mappings  = $this->generateMappings();
-
-        // File version (always the first entry in the object) and must be a positive integer.
-        $sourceMap['version'] = self::VERSION;
-
-        // An optional name of the generated code that this source map is associated with.
-        $file = $this->options['sourceMapFilename'];
-
-        if ($file) {
-            $sourceMap['file'] = $file;
-        }
-
-        // An optional source root, useful for relocating source files on a server or removing repeated values in the
-        // 'sources' entry. This value is prepended to the individual entries in the 'source' field.
-        $root = $this->options['sourceRoot'];
-
-        if ($root) {
-            $sourceMap['sourceRoot'] = $root;
-        }
-
-        // A list of original sources used by the 'mappings' entry.
-        $sourceMap['sources'] = array();
-
-        foreach ($this->sources as $source_uri => $source_filename) {
-            $sourceMap['sources'][] = $this->normalizeFilename($source_filename);
-        }
-
-        // A list of symbol names used by the 'mappings' entry.
-        $sourceMap['names'] = array();
-
-        // A string with the encoded mapping data.
-        $sourceMap['mappings'] = $mappings;
-
-        if ($this->options['outputSourceFiles']) {
-            // An optional list of source content, useful when the 'source' can't be hosted.
-            // The contents are listed in the same order as the sources above.
-            // 'null' may be used if some original sources should be retrieved by name.
-            $sourceMap['sourcesContent'] = $this->getSourcesContent();
-        }
-
-        // less.js compat fixes
-        if (count($sourceMap['sources']) && empty($sourceMap['sourceRoot'])) {
-            unset($sourceMap['sourceRoot']);
-        }
-
-        return json_encode($sourceMap);
-    }
-
-    /**
-     * Returns the sources contents
-     *
-     * @return array|null
-     */
-    protected function getSourcesContent()
-    {
-        if (empty($this->sources)) {
-            return null;
-        }
-
-        $content = array();
-
-        foreach ($this->sources as $sourceFile) {
-            $content[] = file_get_contents($sourceFile);
-        }
-
-        return $content;
-    }
-
-    /**
-     * Generates the mappings string
-     *
-     * @return string
-     */
-    public function generateMappings()
-    {
-        if (! count($this->mappings)) {
-            return '';
-        }
-
-        $this->source_keys = array_flip(array_keys($this->sources));
-
-        // group mappings by generated line number.
-        $groupedMap = $groupedMapEncoded = array();
-
-        foreach ($this->mappings as $m) {
-            $groupedMap[$m['generated_line']][] = $m;
-        }
-
-        ksort($groupedMap);
-        $lastGeneratedLine = $lastOriginalIndex = $lastOriginalLine = $lastOriginalColumn = 0;
-
-        foreach ($groupedMap as $lineNumber => $line_map) {
-            while (++$lastGeneratedLine < $lineNumber) {
-                $groupedMapEncoded[] = ';';
-            }
-
-            $lineMapEncoded = array();
-            $lastGeneratedColumn = 0;
-
-            foreach ($line_map as $m) {
-                $mapEncoded = $this->encoder->encode($m['generated_column'] - $lastGeneratedColumn);
-                $lastGeneratedColumn = $m['generated_column'];
-
-                // find the index
-                if ($m['source_file']) {
-                    $index = $this->findFileIndex($m['source_file']);
-
-                    if ($index !== false) {
-                        $mapEncoded .= $this->encoder->encode($index - $lastOriginalIndex);
-                        $lastOriginalIndex = $index;
-                        // lines are stored 0-based in SourceMap spec version 3
-                        $mapEncoded .= $this->encoder->encode($m['original_line'] - 1 - $lastOriginalLine);
-                        $lastOriginalLine = $m['original_line'] - 1;
-                        $mapEncoded .= $this->encoder->encode($m['original_column'] - $lastOriginalColumn);
-                        $lastOriginalColumn = $m['original_column'];
-                    }
-                }
-
-                $lineMapEncoded[] = $mapEncoded;
-            }
-
-            $groupedMapEncoded[] = implode(',', $lineMapEncoded) . ';';
-        }
-
-        return rtrim(implode($groupedMapEncoded), ';');
-    }
-
-    /**
-     * Finds the index for the filename
-     *
-     * @param string $filename
-     *
-     * @return integer|false
-     */
-    protected function findFileIndex($filename)
-    {
-        return $this->source_keys[$filename];
-    }
-
-    protected function normalizeFilename($filename)
-    {
-        $filename = $this->fixWindowsPath($filename);
-        $rootpath = $this->options['sourceMapRootpath'];
-        $basePath = $this->options['sourceMapBasepath'];
-
-        // "Trim" the 'sourceMapBasepath' from the output filename.
-        if (strpos($filename, $basePath) === 0) {
-            $filename = substr($filename, strlen($basePath));
-        }
-
-        // Remove extra leading path separators.
-        if (strpos($filename, '\\') === 0 || strpos($filename, '/') === 0) {
-            $filename = substr($filename, 1);
-        }
-
-        return $rootpath . $filename;
-    }
-
-    /**
-     * Fix windows paths
-     *
-     * @param string  $path
-     * @param boolean $addEndSlash
-     *
-     * @return string
-     */
-    public function fixWindowsPath($path, $addEndSlash = false)
-    {
-        $slash = ($addEndSlash) ? '/' : '';
-
-        if (! empty($path)) {
-            $path = str_replace('\\', '/', $path);
-            $path = rtrim($path, '/') . $slash;
-        }
-
-        return $path;
-    }
-}
diff --git a/inc/scssphp--old/src/Type.php b/inc/scssphp--old/src/Type.php
deleted file mode 100644
index e84c47e..0000000
--- a/inc/scssphp--old/src/Type.php
+++ /dev/null
@@ -1,69 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp;
-
-/**
- * Block/node types
- *
- * @author Anthon Pang <anthon.pang@gmail.com>
- */
-class Type
-{
-    const T_ASSIGN = 'assign';
-    const T_AT_ROOT = 'at-root';
-    const T_BLOCK = 'block';
-    const T_BREAK = 'break';
-    const T_CHARSET = 'charset';
-    const T_COLOR = 'color';
-    const T_COMMENT = 'comment';
-    const T_CONTINUE = 'continue';
-    const T_CONTROL = 'control';
-    const T_DEBUG = 'debug';
-    const T_DIRECTIVE = 'directive';
-    const T_EACH = 'each';
-    const T_ELSE = 'else';
-    const T_ELSEIF = 'elseif';
-    const T_ERROR = 'error';
-    const T_EXPRESSION = 'exp';
-    const T_EXTEND = 'extend';
-    const T_FOR = 'for';
-    const T_FUNCTION = 'function';
-    const T_FUNCTION_CALL = 'fncall';
-    const T_HSL = 'hsl';
-    const T_IF = 'if';
-    const T_IMPORT = 'import';
-    const T_INCLUDE = 'include';
-    const T_INTERPOLATE = 'interpolate';
-    const T_INTERPOLATED = 'interpolated';
-    const T_KEYWORD = 'keyword';
-    const T_LIST = 'list';
-    const T_MAP = 'map';
-    const T_MEDIA = 'media';
-    const T_MEDIA_EXPRESSION = 'mediaExp';
-    const T_MEDIA_TYPE = 'mediaType';
-    const T_MEDIA_VALUE = 'mediaValue';
-    const T_MIXIN = 'mixin';
-    const T_MIXIN_CONTENT = 'mixin_content';
-    const T_NESTED_PROPERTY = 'nestedprop';
-    const T_NOT = 'not';
-    const T_NULL = 'null';
-    const T_NUMBER = 'number';
-    const T_RETURN = 'return';
-    const T_ROOT = 'root';
-    const T_SCSSPHP_IMPORT_ONCE = 'scssphp-import-once';
-    const T_SELF = 'self';
-    const T_STRING = 'string';
-    const T_UNARY = 'unary';
-    const T_VARIABLE = 'var';
-    const T_WARN = 'warn';
-    const T_WHILE = 'while';
-}
diff --git a/inc/scssphp--old/src/Util.php b/inc/scssphp--old/src/Util.php
deleted file mode 100644
index 7526e02..0000000
--- a/inc/scssphp--old/src/Util.php
+++ /dev/null
@@ -1,70 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp;
-
-use Leafo\ScssPhp\Base\Range;
-use Leafo\ScssPhp\Exception\RangeException;
-
-/**
- * Utilty functions
- *
- * @author Anthon Pang <anthon.pang@gmail.com>
- */
-class Util
-{
-    /**
-     * Asserts that `value` falls within `range` (inclusive), leaving
-     * room for slight floating-point errors.
-     *
-     * @param string                    $name  The name of the value. Used in the error message.
-     * @param \Leafo\ScssPhp\Base\Range $range Range of values.
-     * @param array                     $value The value to check.
-     * @param string                    $unit  The unit of the value. Used in error reporting.
-     *
-     * @return mixed `value` adjusted to fall within range, if it was outside by a floating-point margin.
-     *
-     * @throws \Leafo\ScssPhp\Exception\RangeException
-     */
-    public static function checkRange($name, Range $range, $value, $unit = '')
-    {
-        $val = $value[1];
-        $grace = new Range(-0.00001, 0.00001);
-
-        if ($range->includes($val)) {
-            return $val;
-        }
-
-        if ($grace->includes($val - $range->first)) {
-            return $range->first;
-        }
-
-        if ($grace->includes($val - $range->last)) {
-            return $range->last;
-        }
-
-        throw new RangeException("$name {$val} must be between {$range->first} and {$range->last}$unit");
-    }
-
-    /**
-     * Encode URI component
-     *
-     * @param string $string
-     *
-     * @return string
-     */
-    public static function encodeURIComponent($string)
-    {
-        $revert = array('%21' => '!', '%2A' => '*', '%27' => "'", '%28' => '(', '%29' => ')');
-
-        return strtr(rawurlencode($string), $revert);
-    }
-}
diff --git a/inc/scssphp--old/src/Version.php b/inc/scssphp--old/src/Version.php
deleted file mode 100644
index 3b8dcd0..0000000
--- a/inc/scssphp--old/src/Version.php
+++ /dev/null
@@ -1,22 +0,0 @@
-<?php
-/**
- * SCSSPHP
- *
- * @copyright 2012-2018 Leaf Corcoran
- *
- * @license http://opensource.org/licenses/MIT MIT
- *
- * @link http://leafo.github.io/scssphp
- */
-
-namespace Leafo\ScssPhp;
-
-/**
- * SCSSPHP version
- *
- * @author Leaf Corcoran <leafot@gmail.com>
- */
-class Version
-{
-    const VERSION = 'v0.7.5';
-}
diff --git a/inc/theme_plus.php b/inc/theme_plus.php
index 9d34e97..569bfab 100644
--- a/inc/theme_plus.php
+++ b/inc/theme_plus.php
@@ -293,8 +293,14 @@ function the_headPattern(){
     $center = 'single-center';
     $header = 'single-header';
     $ava = akina_option('focus_logo', '') ? akina_option('focus_logo', '') : get_avatar_url(get_the_author_meta('user_email'));
+    global $user_ID; 
+    if($user_ID && current_user_can('level_10')) {
+        $edit_this_post_link = '<span class="bull">·</span><a href="'.get_edit_post_link().'">EDIT</a>';
+    } else {
+        $edit_this_post_link = '';
+    }
     $t .= the_title( '<h1 class="entry-title">', '</h1>', false);
-    $t .= '<p class="entry-census"><span><a href="'. esc_url(get_author_posts_url(get_the_author_meta('ID'),get_the_author_meta( 'user_nicename' ))) .'"><img src="'. get_avatar_url( get_the_author_meta('ID'), 64 )/*$ava*/ .'"></a></span><span><a href="'. esc_url(get_author_posts_url(get_the_author_meta('ID'),get_the_author_meta( 'user_nicename' ))) .'">'. get_the_author() .'</a></span><span class="bull">·</span>'. poi_time_since(get_post_time('U', true),false,true) .'<span class="bull">·</span>'. get_post_views(get_the_ID()) .' 次阅读</p>';
+    $t .= '<p class="entry-census"><span><a href="'. esc_url(get_author_posts_url(get_the_author_meta('ID'),get_the_author_meta( 'user_nicename' ))) .'"><img src="'. get_avatar_url( get_the_author_meta('ID'), 64 )/*$ava*/ .'"></a></span><span><a href="'. esc_url(get_author_posts_url(get_the_author_meta('ID'),get_the_author_meta( 'user_nicename' ))) .'">'. get_the_author() .'</a></span><span class="bull">·</span>'. poi_time_since(get_post_time('U', true),false,true) .'<span class="bull">·</span>'. get_post_views(get_the_ID()) .' 次阅读'.$edit_this_post_link.'</p>';
     endwhile; endif;
   }elseif(is_page()){
     $full_image_url = $full_image_url[0];
diff --git a/options.php b/options.php
index 8798ef8..ec192ab 100644
--- a/options.php
+++ b/options.php
@@ -704,7 +704,7 @@ function optionsframework_options() {
         'name' => __("面板主色调A", 'akina'),
         'id' => 'dash_scheme_color_a',
         'std' => "#c6742b",
-        'desc' => __('', ''),
+        'desc' => __('<i>(array) (optional)</i> An array of CSS color definitions which are used to give the user a feel for the theme.', ''),
         'type' => "color"
     );
     
@@ -712,7 +712,7 @@ function optionsframework_options() {
         'name' => __("面板主色调B", 'akina'),
         'id' => 'dash_scheme_color_b',
         'std' => "#d88e4c",
-        'desc' => __('', ''),
+        'desc' => __('<i>(array) (optional)</i> An array of CSS color definitions which are used to give the user a feel for the theme.', ''),
         'type' => "color"
     );
     
@@ -720,7 +720,7 @@ function optionsframework_options() {
         'name' => __("面板主色调C", 'akina'),
         'id' => 'dash_scheme_color_c',
         'std' => "#695644",
-        'desc' => __('', ''),
+        'desc' => __('<i>(array) (optional)</i> An array of CSS color definitions which are used to give the user a feel for the theme.', ''),
         'type' => "color"
     );
     
@@ -728,7 +728,7 @@ function optionsframework_options() {
         'name' => __("面板主色调D", 'akina'),
         'id' => 'dash_scheme_color_d',
         'std' => "#a19780",
-        'desc' => __('', ''),
+        'desc' => __('<i>(array) (optional)</i> An array of CSS color definitions which are used to give the user a feel for the theme.', ''),
         'type' => "color"
     );
     
@@ -736,7 +736,7 @@ function optionsframework_options() {
         'name' => __("面板图标配色——base", 'akina'),
         'id' => 'dash_scheme_color_base',
         'std' => "#e5f8ff",
-        'desc' => __('', ''),
+        'desc' => __('<i>(array) (optional)</i> An array of CSS color definitions used to color any SVG icons.', ''),
         'type' => "color"
     );
     
@@ -744,7 +744,7 @@ function optionsframework_options() {
         'name' => __("面板图标配色——focus", 'akina'),
         'id' => 'dash_scheme_color_focus',
         'std' => "#fff",
-        'desc' => __('', ''),
+        'desc' => __('<i>(array) (optional)</i> An array of CSS color definitions used to color any SVG icons.', ''),
         'type' => "color"
     );
     
@@ -752,7 +752,7 @@ function optionsframework_options() {
         'name' => __("面板图标配色——current", 'akina'),
         'id' => 'dash_scheme_color_current',
         'std' => "#fff",
-        'desc' => __('', ''),
+        'desc' => __('<i>(array) (optional)</i> An array of CSS color definitions used to color any SVG icons.', ''),
         'type' => "color"
     );