Phlexy\Lexer\Stateless\UsingPregReplace::lex PHP Method

    public function lex($string)
    {
        $tokens = array();
        $line = 1;
        // 5.3 can't access $this in closure, so put it in a variable
        $offsetToTokenMap = $this->offsetToTokenMap;
        $offsetToLengthMap = $this->offsetToLengthMap;
        $res = preg_replace_callback($this->compiledRegex, function ($matches) use($offsetToTokenMap, $offsetToLengthMap, &$tokens, &$line) {
            // find the first non-empty element (but skipping $matches[0]) using a quick for loop
            for ($i = 2; '' === $matches[$i]; ++$i) {
            }
            $realMatches = array();
            for ($j = 1, $length = $offsetToLengthMap[$i - 2]; $j < $length; ++$j) {
                if (isset($matches[$i + $j])) {
                    $realMatches[$j] = $matches[$i + $j];
                }
            }
            if (!empty($realMatches)) {
                $tokens[] = array($offsetToTokenMap[$i - 2], $line, $matches[0], $realMatches);
            } else {
                $tokens[] = array($offsetToTokenMap[$i - 2], $line, $matches[0]);
            }
            $line += substr_count($matches[0], "\n");
            return '';
        }, $string);
        if ('' !== $res) {
            throw new \Phlexy\LexingException(sprintf('Unexpected character "%s" on line %d', $res[0], $line));
        }
        return $tokens;
    }

 public function parse($filename)
 {
     if (!file_exists($filename)) {
         throw new \Exception('File not found "' . $filename . '"');
     }
     $tokens = $this->lexer->lex(file_get_contents($filename));
     $current_node = [static::T_ROOT];
     $current_node_level = 0;
     /** @var Node|null $node */
     $node = null;
     $nodes = [];
     /** @var Rewrite|null $rewrite */
     $rewrite = null;
     $variable_key = $variable_value = null;
     $config = new Collection([]);
     foreach ($tokens as $token) {
         $line_context = " (" . $filename . "#" . $token[1] . ")";
         switch ($token[0]) {
             /** Nodes */
             case static::T_NODE_OPEN:
                 if (!in_array($current_node[$current_node_level], [static::T_ROOT]) && in_array($token[3][1], ['VirtualHost', 'Directory'])) {
                     throw new SyntaxErrorException('Syntax error, expected T_ROOT given [Node: ' . $token[3][1] . '] ' . $this->get_constant_name($current_node[$current_node_level]) . ' ' . $line_context);
                 }
                 if (!in_array($current_node[$current_node_level], [static::T_NODE_OPEN]) && in_array($token[3][1], ['IfModule'])) {
                     throw new SyntaxErrorException('Syntax error, expected T_NODE_OPEN given [Node: ' . $token[3][1] . '] ' . $this->get_constant_name($current_node[$current_node_level]) . ' ' . $line_context);
                 }
                 switch ($token[3][1]) {
                     case 'VirtualHost':
                         $node = new VirtualHost($token['3']['2']);
                         break;
                     case 'Directory':
                         $node = new Directory($token['3']['2']);
                         break;
                     case 'IfModule':
                         if (empty($node) || !$node instanceof Node) {
                             throw new SyntaxErrorException('No current node defined ' . $line_context);
                         }
                         $nodes[$current_node_level] = $node;
                         $current_node_level++;
                         $node = new IfModule($token['3']['2']);
                         break;
                 }
                 $current_node[$current_node_level] = static::T_NODE_OPEN;
                 break;
             case static::T_NODE_CLOSE:
                 if ($current_node_level > 0) {
                     $current_node_level--;
                     $nodes[$current_node_level]->children[] = $node;
                     $node = $nodes[$current_node_level];
                     unset($nodes[$current_node_level]);
                 } else {
                     if (!in_array($current_node[$current_node_level], [static::T_NODE_OPEN])) {
                         throw new SyntaxErrorException('Syntax error, expected T_NODE_OPEN given ' . $this->get_constant_name($current_node[$current_node_level]) . $line_context);
                     }
                     $config[] = $node;
                     $current_node[$current_node_level] = static::T_ROOT;
                     unset($node);
                 }
                 break;
             case static::T_VARIABLE:
                 if (!in_array($current_node[$current_node_level], [static::T_NODE_OPEN])) {
                     throw new SyntaxErrorException('Syntax error, expected T_NODE_OPEN given ' . $this->get_constant_name($current_node[$current_node_level]) . $line_context);
                 }
                 $variable_key = trim($token[3][1]);
                 $variable_value = trim($token[3][2]);
                 $current_node[$current_node_level] = static::T_VARIABLE;
                 break;
             case static::T_CONTINUE_VARIABLE:
                 if (!in_array($current_node[$current_node_level], [static::T_VARIABLE])) {
                     throw new SyntaxErrorException('Syntax error, expected T_VARIABLE given ' . $this->get_constant_name($current_node[$current_node_level]) . $line_context);
                 }
                 if ($variable_key === null || $variable_value === null) {
                     throw new SyntaxErrorException('Syntax error, no variable key or value found ' . $line_context);
                 }
                 $variable_value .= ' ' . trim($token[3][1]);
                 break;
             case static::T_LINEBREAK:
                 switch ($current_node[$current_node_level]) {
                     case static::T_VARIABLE:
                         if ($variable_key === null || $variable_value === null) {
                             throw new SyntaxErrorException('Syntax error, no variable key or value found ' . $line_context);
                         }
                         if ($node === null) {
                             throw new SyntaxErrorException('No node defined ' . $line_context);
                         }
                         if (in_array($variable_key, ['RewriteCond', 'RewriteRule'])) {
                             $rewrite || ($rewrite = new Rewrite());
                             switch ($variable_key) {
                                 case 'RewriteCond':
                                     $rewrite->conditions[] = $variable_value;
                                     break;
                                 case 'RewriteRule':
                                     $rewrite->rules[] = $variable_value;
                                     if (preg_match('/,?L\\]$/', $variable_value)) {
                                         $node['Rewrite'] = $rewrite;
                                         $rewrite = null;
                                     }
                                     break;
                             }
                         } else {
                             if ($rewrite !== null) {
                                 $node['Rewrite'] = $rewrite;
                                 $rewrite = null;
                             }
                             $node[$variable_key] = $variable_value;
                         }
                         $variable_key = $variable_value = null;
                         $current_node[$current_node_level] = static::T_NODE_OPEN;
                         break;
                 }
                 break;
         }
     }
     if ($current_node[0] != static::T_ROOT) {
         $line_context = " (" . $filename . "#EOF)";
         throw new SyntaxErrorException('Syntax error, expected T_ROOT given ' . $this->get_constant_name($current_node[0]) . $line_context);
     }
     return $config;
 }