vendor/twig/twig/src/Lexer.php line 182

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  1. <?php
  3. /*
  4.  * This file is part of Twig.
  5.  *
  6.  * (c) Fabien Potencier
  7.  * (c) Armin Ronacher
  8.  *
  9.  * For the full copyright and license information, please view the LICENSE
  10.  * file that was distributed with this source code.
  11.  */
  13. namespace Twig;
  15. use Twig\Error\SyntaxError;
  17. /**
  18.  * @author Fabien Potencier <fabien@symfony.com>
  19.  */
  20. class Lexer
  21. {
  22.     private $isInitialized = false;
  24.     private $tokens;
  25.     private $code;
  26.     private $cursor;
  27.     private $lineno;
  28.     private $end;
  29.     private $state;
  30.     private $states;
  31.     private $brackets;
  32.     private $env;
  33.     private $source;
  34.     private $options;
  35.     private $regexes;
  36.     private $position;
  37.     private $positions;
  38.     private $currentVarBlockLine;
  40.     public const STATE_DATA = 0;
  41.     public const STATE_BLOCK = 1;
  42.     public const STATE_VAR = 2;
  43.     public const STATE_STRING = 3;
  44.     public const STATE_INTERPOLATION = 4;
  46.     public const REGEX_NAME = '/[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*/A';
  47.     public const REGEX_STRING = '/"([^#"\\\\]*(?:\\\\.[^#"\\\\]*)*)"|\'([^\'\\\\]*(?:\\\\.[^\'\\\\]*)*)\'/As';
  49.     public const REGEX_NUMBER = '/(?(DEFINE)
  50.         (?<LNUM>[0-9]+(_[0-9]+)*)               # Integers (with underscores)   123_456
  51.         (?<FRAC>\.(?&LNUM))                     # Fractional part               .456
  52.         (?<EXPONENT>[eE][+-]?(?&LNUM))          # Exponent part                 E+10
  53.         (?<DNUM>(?&LNUM)(?:(?&FRAC))?)          # Decimal number                123_456.456
  54.     )(?:(?&DNUM)(?:(?&EXPONENT))?)              #                               123_456.456E+10
  55.     /Ax';
  56.     
  57.     public const REGEX_DQ_STRING_DELIM = '/"/A';
  58.     public const REGEX_DQ_STRING_PART = '/[^#"\\\\]*(?:(?:\\\\.|#(?!\{))[^#"\\\\]*)*/As';
  59.     public const REGEX_INLINE_COMMENT = '/#[^\n]*/A';
  60.     public const PUNCTUATION = '()[]{}?:.,|';
  62.     private const SPECIAL_CHARS = [
  63.         'f' => "\f",
  64.         'n' => "\n",
  65.         'r' => "\r",
  66.         't' => "\t",
  67.         'v' => "\v",
  68.     ];
  70.     public function __construct(Environment $env, array $options = [])
  71.     {
  72.         $this->env = $env;
  74.         $this->options = array_merge([
  75.             'tag_comment' => ['{#', '#}'],
  76.             'tag_block' => ['{%', '%}'],
  77.             'tag_variable' => ['{{', '}}'],
  78.             'whitespace_trim' => '-',
  79.             'whitespace_line_trim' => '~',
  80.             'whitespace_line_chars' => ' \t\0\x0B',
  81.             'interpolation' => ['#{', '}'],
  82.         ], $options);
  83.     }
  85.     private function initialize()
  86.     {
  87.         if ($this->isInitialized) {
  88.             return;
  89.         }
  91.         // when PHP 7.3 is the min version, we will be able to remove the '#' part in preg_quote as it's part of the default
  92.         $this->regexes = [
  93.             // }}
  94.             'lex_var' => '{
  95.                 \s*
  96.                 (?:'.
  97.                     preg_quote($this->options['whitespace_trim'].$this->options['tag_variable'][1], '#').'\s*'. // -}}\s*
  98.                     '|'.
  99.                     preg_quote($this->options['whitespace_line_trim'].$this->options['tag_variable'][1], '#').'['.$this->options['whitespace_line_chars'].']*'. // ~}}[ \t\0\x0B]*
  100.                     '|'.
  101.                     preg_quote($this->options['tag_variable'][1], '#'). // }}
  102.                 ')
  103.             }Ax',
  105.             // %}
  106.             'lex_block' => '{
  107.                 \s*
  108.                 (?:'.
  109.                     preg_quote($this->options['whitespace_trim'].$this->options['tag_block'][1], '#').'\s*\n?'. // -%}\s*\n?
  110.                     '|'.
  111.                     preg_quote($this->options['whitespace_line_trim'].$this->options['tag_block'][1], '#').'['.$this->options['whitespace_line_chars'].']*'. // ~%}[ \t\0\x0B]*
  112.                     '|'.
  113.                     preg_quote($this->options['tag_block'][1], '#').'\n?'. // %}\n?
  114.                 ')
  115.             }Ax',
  117.             // {% endverbatim %}
  118.             'lex_raw_data' => '{'.
  119.                 preg_quote($this->options['tag_block'][0], '#'). // {%
  120.                 '('.
  121.                     $this->options['whitespace_trim']. // -
  122.                     '|'.
  123.                     $this->options['whitespace_line_trim']. // ~
  124.                 ')?\s*endverbatim\s*'.
  125.                 '(?:'.
  126.                     preg_quote($this->options['whitespace_trim'].$this->options['tag_block'][1], '#').'\s*'. // -%}
  127.                     '|'.
  128.                     preg_quote($this->options['whitespace_line_trim'].$this->options['tag_block'][1], '#').'['.$this->options['whitespace_line_chars'].']*'. // ~%}[ \t\0\x0B]*
  129.                     '|'.
  130.                     preg_quote($this->options['tag_block'][1], '#'). // %}
  131.                 ')
  132.             }sx',
  134.             'operator' => $this->getOperatorRegex(),
  136.             // #}
  137.             'lex_comment' => '{
  138.                 (?:'.
  139.                     preg_quote($this->options['whitespace_trim'].$this->options['tag_comment'][1], '#').'\s*\n?'. // -#}\s*\n?
  140.                     '|'.
  141.                     preg_quote($this->options['whitespace_line_trim'].$this->options['tag_comment'][1], '#').'['.$this->options['whitespace_line_chars'].']*'. // ~#}[ \t\0\x0B]*
  142.                     '|'.
  143.                     preg_quote($this->options['tag_comment'][1], '#').'\n?'. // #}\n?
  144.                 ')
  145.             }sx',
  147.             // verbatim %}
  148.             'lex_block_raw' => '{
  149.                 \s*verbatim\s*
  150.                 (?:'.
  151.                     preg_quote($this->options['whitespace_trim'].$this->options['tag_block'][1], '#').'\s*'. // -%}\s*
  152.                     '|'.
  153.                     preg_quote($this->options['whitespace_line_trim'].$this->options['tag_block'][1], '#').'['.$this->options['whitespace_line_chars'].']*'. // ~%}[ \t\0\x0B]*
  154.                     '|'.
  155.                     preg_quote($this->options['tag_block'][1], '#'). // %}
  156.                 ')
  157.             }Asx',
  159.             'lex_block_line' => '{\s*line\s+(\d+)\s*'.preg_quote($this->options['tag_block'][1], '#').'}As',
  161.             // {{ or {% or {#
  162.             'lex_tokens_start' => '{
  163.                 ('.
  164.                     preg_quote($this->options['tag_variable'][0], '#'). // {{
  165.                     '|'.
  166.                     preg_quote($this->options['tag_block'][0], '#'). // {%
  167.                     '|'.
  168.                     preg_quote($this->options['tag_comment'][0], '#'). // {#
  169.                 ')('.
  170.                     preg_quote($this->options['whitespace_trim'], '#'). // -
  171.                     '|'.
  172.                     preg_quote($this->options['whitespace_line_trim'], '#'). // ~
  173.                 ')?
  174.             }sx',
  175.             'interpolation_start' => '{'.preg_quote($this->options['interpolation'][0], '#').'\s*}A',
  176.             'interpolation_end' => '{\s*'.preg_quote($this->options['interpolation'][1], '#').'}A',
  177.         ];
  179.         $this->isInitialized = true;
  180.     }
  182.     public function tokenize(Source $source): TokenStream
  183.     {
  184.         $this->initialize();
  186.         $this->source = $source;
  187.         $this->code = str_replace(["\r\n", "\r"], "\n", $source->getCode());
  188.         $this->cursor = 0;
  189.         $this->lineno = 1;
  190.         $this->end = \strlen($this->code);
  191.         $this->tokens = [];
  192.         $this->state = self::STATE_DATA;
  193.         $this->states = [];
  194.         $this->brackets = [];
  195.         $this->position = -1;
  197.         // find all token starts in one go
  198.         preg_match_all($this->regexes['lex_tokens_start'], $this->code, $matches, \PREG_OFFSET_CAPTURE);
  199.         $this->positions = $matches;
  201.         while ($this->cursor < $this->end) {
  202.             // dispatch to the lexing functions depending
  203.             // on the current state
  204.             switch ($this->state) {
  205.                 case self::STATE_DATA:
  206.                     $this->lexData();
  207.                     break;
  209.                 case self::STATE_BLOCK:
  210.                     $this->lexBlock();
  211.                     break;
  213.                 case self::STATE_VAR:
  214.                     $this->lexVar();
  215.                     break;
  217.                 case self::STATE_STRING:
  218.                     $this->lexString();
  219.                     break;
  221.                 case self::STATE_INTERPOLATION:
  222.                     $this->lexInterpolation();
  223.                     break;
  224.             }
  225.         }
  227.         $this->pushToken(Token::EOF_TYPE);
  229.         if ($this->brackets) {
  230.             [$expect, $lineno] = array_pop($this->brackets);
  231.             throw new SyntaxError(\sprintf('Unclosed "%s".', $expect), $lineno, $this->source);
  232.         }
  234.         return new TokenStream($this->tokens, $this->source);
  235.     }
  237.     private function lexData(): void
  238.     {
  239.         // if no matches are left we return the rest of the template as simple text token
  240.         if ($this->position == \count($this->positions[0]) - 1) {
  241.             $this->pushToken(Token::TEXT_TYPE, substr($this->code, $this->cursor));
  242.             $this->cursor = $this->end;
  244.             return;
  245.         }
  247.         // Find the first token after the current cursor
  248.         $position = $this->positions[0][++$this->position];
  249.         while ($position[1] < $this->cursor) {
  250.             if ($this->position == \count($this->positions[0]) - 1) {
  251.                 return;
  252.             }
  253.             $position = $this->positions[0][++$this->position];
  254.         }
  256.         // push the template text first
  257.         $text = $textContent = substr($this->code, $this->cursor, $position[1] - $this->cursor);
  259.         // trim?
  260.         if (isset($this->positions[2][$this->position][0])) {
  261.             if ($this->options['whitespace_trim'] === $this->positions[2][$this->position][0]) {
  262.                 // whitespace_trim detected ({%-, {{- or {#-)
  263.                 $text = rtrim($text);
  264.             } elseif ($this->options['whitespace_line_trim'] === $this->positions[2][$this->position][0]) {
  265.                 // whitespace_line_trim detected ({%~, {{~ or {#~)
  266.                 // don't trim \r and \n
  267.                 $text = rtrim($text, " \t\0\x0B");
  268.             }
  269.         }
  270.         $this->pushToken(Token::TEXT_TYPE, $text);
  271.         $this->moveCursor($textContent.$position[0]);
  273.         switch ($this->positions[1][$this->position][0]) {
  274.             case $this->options['tag_comment'][0]:
  275.                 $this->lexComment();
  276.                 break;
  278.             case $this->options['tag_block'][0]:
  279.                 // raw data?
  280.                 if (preg_match($this->regexes['lex_block_raw'], $this->code, $match, 0, $this->cursor)) {
  281.                     $this->moveCursor($match[0]);
  282.                     $this->lexRawData();
  283.                 // {% line \d+ %}
  284.                 } elseif (preg_match($this->regexes['lex_block_line'], $this->code, $match, 0, $this->cursor)) {
  285.                     $this->moveCursor($match[0]);
  286.                     $this->lineno = (int) $match[1];
  287.                 } else {
  288.                     $this->pushToken(Token::BLOCK_START_TYPE);
  289.                     $this->pushState(self::STATE_BLOCK);
  290.                     $this->currentVarBlockLine = $this->lineno;
  291.                 }
  292.                 break;
  294.             case $this->options['tag_variable'][0]:
  295.                 $this->pushToken(Token::VAR_START_TYPE);
  296.                 $this->pushState(self::STATE_VAR);
  297.                 $this->currentVarBlockLine = $this->lineno;
  298.                 break;
  299.         }
  300.     }
  302.     private function lexBlock(): void
  303.     {
  304.         if (!$this->brackets && preg_match($this->regexes['lex_block'], $this->code, $match, 0, $this->cursor)) {
  305.             $this->pushToken(Token::BLOCK_END_TYPE);
  306.             $this->moveCursor($match[0]);
  307.             $this->popState();
  308.         } else {
  309.             $this->lexExpression();
  310.         }
  311.     }
  313.     private function lexVar(): void
  314.     {
  315.         if (!$this->brackets && preg_match($this->regexes['lex_var'], $this->code, $match, 0, $this->cursor)) {
  316.             $this->pushToken(Token::VAR_END_TYPE);
  317.             $this->moveCursor($match[0]);
  318.             $this->popState();
  319.         } else {
  320.             $this->lexExpression();
  321.         }
  322.     }
  324.     private function lexExpression(): void
  325.     {
  326.         // whitespace
  327.         if (preg_match('/\s+/A', $this->code, $match, 0, $this->cursor)) {
  328.             $this->moveCursor($match[0]);
  330.             if ($this->cursor >= $this->end) {
  331.                 throw new SyntaxError(\sprintf('Unclosed "%s".', self::STATE_BLOCK === $this->state ? 'block' : 'variable'), $this->currentVarBlockLine, $this->source);
  332.             }
  333.         }
  335.         // spread operator
  336.         if ('.' === $this->code[$this->cursor] && ($this->cursor + 2 < $this->end) && '.' === $this->code[$this->cursor + 1] && '.' === $this->code[$this->cursor + 2]) {
  337.             $this->pushToken(Token::SPREAD_TYPE, '...');
  338.             $this->moveCursor('...');
  339.         }
  340.         // arrow function
  341.         elseif ('=' === $this->code[$this->cursor] && ($this->cursor + 1 < $this->end) && '>' === $this->code[$this->cursor + 1]) {
  342.             $this->pushToken(Token::ARROW_TYPE, '=>');
  343.             $this->moveCursor('=>');
  344.         }
  345.         // operators
  346.         elseif (preg_match($this->regexes['operator'], $this->code, $match, 0, $this->cursor)) {
  347.             $this->pushToken(Token::OPERATOR_TYPE, preg_replace('/\s+/', ' ', $match[0]));
  348.             $this->moveCursor($match[0]);
  349.         }
  350.         // names
  351.         elseif (preg_match(self::REGEX_NAME, $this->code, $match, 0, $this->cursor)) {
  352.             $this->pushToken(Token::NAME_TYPE, $match[0]);
  353.             $this->moveCursor($match[0]);
  354.         }
  355.         // numbers
  356.         elseif (preg_match(self::REGEX_NUMBER, $this->code, $match, 0, $this->cursor)) {
  357.             $this->pushToken(Token::NUMBER_TYPE, 0 + str_replace('_', '', $match[0]));
  358.             $this->moveCursor($match[0]);
  359.         }
  360.         // punctuation
  361.         elseif (str_contains(self::PUNCTUATION, $this->code[$this->cursor])) {
  362.             // opening bracket
  363.             if (str_contains('([{', $this->code[$this->cursor])) {
  364.                 $this->brackets[] = [$this->code[$this->cursor], $this->lineno];
  365.             }
  366.             // closing bracket
  367.             elseif (str_contains(')]}', $this->code[$this->cursor])) {
  368.                 if (!$this->brackets) {
  369.                     throw new SyntaxError(\sprintf('Unexpected "%s".', $this->code[$this->cursor]), $this->lineno, $this->source);
  370.                 }
  372.                 [$expect, $lineno] = array_pop($this->brackets);
  373.                 if ($this->code[$this->cursor] != strtr($expect, '([{', ')]}')) {
  374.                     throw new SyntaxError(\sprintf('Unclosed "%s".', $expect), $lineno, $this->source);
  375.                 }
  376.             }
  378.             $this->pushToken(Token::PUNCTUATION_TYPE, $this->code[$this->cursor]);
  379.             ++$this->cursor;
  380.         }
  381.         // strings
  382.         elseif (preg_match(self::REGEX_STRING, $this->code, $match, 0, $this->cursor)) {
  383.             $this->pushToken(Token::STRING_TYPE, $this->stripcslashes(substr($match[0], 1, -1), substr($match[0], 0, 1)));
  384.             $this->moveCursor($match[0]);
  385.         }
  386.         // opening double quoted string
  387.         elseif (preg_match(self::REGEX_DQ_STRING_DELIM, $this->code, $match, 0, $this->cursor)) {
  388.             $this->brackets[] = ['"', $this->lineno];
  389.             $this->pushState(self::STATE_STRING);
  390.             $this->moveCursor($match[0]);
  391.         }
  392.         // inline comment
  393.         elseif (preg_match(self::REGEX_INLINE_COMMENT, $this->code, $match, 0, $this->cursor)) {
  394.             $this->moveCursor($match[0]);
  395.         }
  396.         // unlexable
  397.         else {
  398.             throw new SyntaxError(\sprintf('Unexpected character "%s".', $this->code[$this->cursor]), $this->lineno, $this->source);
  399.         }
  400.     }
  402.     private function stripcslashes(string $str, string $quoteType): string
  403.     {
  404.         $result = '';
  405.         $length = \strlen($str);
  407.         $i = 0;
  408.         while ($i < $length) {
  409.             if (false === $pos = strpos($str, '\\', $i)) {
  410.                 $result .= substr($str, $i);
  411.                 break;
  412.             }
  414.             $result .= substr($str, $i, $pos - $i);
  415.             $i = $pos + 1;
  417.             if ($i >= $length) {
  418.                 $result .= '\\';
  419.                 break;
  420.             }
  422.             $nextChar = $str[$i];
  424.             if (isset(self::SPECIAL_CHARS[$nextChar])) {
  425.                 $result .= self::SPECIAL_CHARS[$nextChar];
  426.             } elseif ('\\' === $nextChar) {
  427.                 $result .= $nextChar;
  428.             } elseif ("'" === $nextChar || '"' === $nextChar) {
  429.                 if ($nextChar !== $quoteType) {
  430.                     trigger_deprecation('twig/twig', '3.12', 'Character "%s" should not be escaped; the "\" character is ignored in Twig 3 but will not be in Twig 4. Please remove the extra "\" character at position %d in "%s" at line %d.', $nextChar, $i + 1, $this->source->getName(), $this->lineno);
  431.                 }
  432.                 $result .= $nextChar;
  433.             } elseif ('#' === $nextChar && $i + 1 < $length && '{' === $str[$i + 1]) {
  434.                 $result .= '#{';
  435.                 ++$i;
  436.             } elseif ('x' === $nextChar && $i + 1 < $length && ctype_xdigit($str[$i + 1])) {
  437.                 $hex = $str[++$i];
  438.                 if ($i + 1 < $length && ctype_xdigit($str[$i + 1])) {
  439.                     $hex .= $str[++$i];
  440.                 }
  441.                 $result .= \chr(hexdec($hex));
  442.             } elseif (ctype_digit($nextChar) && $nextChar < '8') {
  443.                 $octal = $nextChar;
  444.                 while ($i + 1 < $length && ctype_digit($str[$i + 1]) && $str[$i + 1] < '8' && \strlen($octal) < 3) {
  445.                     $octal .= $str[++$i];
  446.                 }
  447.                 $result .= \chr(octdec($octal));
  448.             } else {
  449.                 trigger_deprecation('twig/twig', '3.12', 'Character "%s" should not be escaped; the "\" character is ignored in Twig 3 but will not be in Twig 4. Please remove the extra "\" character at position %d in "%s" at line %d.', $nextChar, $i + 1, $this->source->getName(), $this->lineno);
  450.                 $result .= $nextChar;
  451.             }
  453.             ++$i;
  454.         }
  456.         return $result;
  457.     }
  459.     private function lexRawData(): void
  460.     {
  461.         if (!preg_match($this->regexes['lex_raw_data'], $this->code, $match, \PREG_OFFSET_CAPTURE, $this->cursor)) {
  462.             throw new SyntaxError('Unexpected end of file: Unclosed "verbatim" block.', $this->lineno, $this->source);
  463.         }
  465.         $text = substr($this->code, $this->cursor, $match[0][1] - $this->cursor);
  466.         $this->moveCursor($text.$match[0][0]);
  468.         // trim?
  469.         if (isset($match[1][0])) {
  470.             if ($this->options['whitespace_trim'] === $match[1][0]) {
  471.                 // whitespace_trim detected ({%-, {{- or {#-)
  472.                 $text = rtrim($text);
  473.             } else {
  474.                 // whitespace_line_trim detected ({%~, {{~ or {#~)
  475.                 // don't trim \r and \n
  476.                 $text = rtrim($text, " \t\0\x0B");
  477.             }
  478.         }
  480.         $this->pushToken(Token::TEXT_TYPE, $text);
  481.     }
  483.     private function lexComment(): void
  484.     {
  485.         if (!preg_match($this->regexes['lex_comment'], $this->code, $match, \PREG_OFFSET_CAPTURE, $this->cursor)) {
  486.             throw new SyntaxError('Unclosed comment.', $this->lineno, $this->source);
  487.         }
  489.         $this->moveCursor(substr($this->code, $this->cursor, $match[0][1] - $this->cursor).$match[0][0]);
  490.     }
  492.     private function lexString(): void
  493.     {
  494.         if (preg_match($this->regexes['interpolation_start'], $this->code, $match, 0, $this->cursor)) {
  495.             $this->brackets[] = [$this->options['interpolation'][0], $this->lineno];
  496.             $this->pushToken(Token::INTERPOLATION_START_TYPE);
  497.             $this->moveCursor($match[0]);
  498.             $this->pushState(self::STATE_INTERPOLATION);
  499.         } elseif (preg_match(self::REGEX_DQ_STRING_PART, $this->code, $match, 0, $this->cursor) && '' !== $match[0]) {
  500.             $this->pushToken(Token::STRING_TYPE, $this->stripcslashes($match[0], '"'));
  501.             $this->moveCursor($match[0]);
  502.         } elseif (preg_match(self::REGEX_DQ_STRING_DELIM, $this->code, $match, 0, $this->cursor)) {
  503.             [$expect, $lineno] = array_pop($this->brackets);
  504.             if ('"' != $this->code[$this->cursor]) {
  505.                 throw new SyntaxError(\sprintf('Unclosed "%s".', $expect), $lineno, $this->source);
  506.             }
  508.             $this->popState();
  509.             ++$this->cursor;
  510.         } else {
  511.             // unlexable
  512.             throw new SyntaxError(\sprintf('Unexpected character "%s".', $this->code[$this->cursor]), $this->lineno, $this->source);
  513.         }
  514.     }
  516.     private function lexInterpolation(): void
  517.     {
  518.         $bracket = end($this->brackets);
  519.         if ($this->options['interpolation'][0] === $bracket[0] && preg_match($this->regexes['interpolation_end'], $this->code, $match, 0, $this->cursor)) {
  520.             array_pop($this->brackets);
  521.             $this->pushToken(Token::INTERPOLATION_END_TYPE);
  522.             $this->moveCursor($match[0]);
  523.             $this->popState();
  524.         } else {
  525.             $this->lexExpression();
  526.         }
  527.     }
  529.     private function pushToken($type, $value = ''): void
  530.     {
  531.         // do not push empty text tokens
  532.         if (Token::TEXT_TYPE === $type && '' === $value) {
  533.             return;
  534.         }
  536.         $this->tokens[] = new Token($type, $value, $this->lineno);
  537.     }
  539.     private function moveCursor($text): void
  540.     {
  541.         $this->cursor += \strlen($text);
  542.         $this->lineno += substr_count($text, "\n");
  543.     }
  545.     private function getOperatorRegex(): string
  546.     {
  547.         $operators = array_merge(
  548.             ['='],
  549.             array_keys($this->env->getUnaryOperators()),
  550.             array_keys($this->env->getBinaryOperators())
  551.         );
  553.         $operators = array_combine($operators, array_map('strlen', $operators));
  554.         arsort($operators);
  556.         $regex = [];
  557.         foreach ($operators as $operator => $length) {
  558.             // an operator that ends with a character must be followed by
  559.             // a whitespace, a parenthesis, an opening map [ or sequence {
  560.             $r = preg_quote($operator, '/');
  561.             if (ctype_alpha($operator[$length - 1])) {
  562.                 $r .= '(?=[\s()\[{])';
  563.             }
  565.             // an operator that begins with a character must not have a dot or pipe before
  566.             if (ctype_alpha($operator[0])) {
  567.                 $r = '(?<![\.\|])'.$r;
  568.             }
  570.             // an operator with a space can be any amount of whitespaces
  571.             $r = preg_replace('/\s+/', '\s+', $r);
  573.             $regex[] = $r;
  574.         }
  576.         return '/'.implode('|', $regex).'/A';
  577.     }
  579.     private function pushState($state): void
  580.     {
  581.         $this->states[] = $this->state;
  582.         $this->state = $state;
  583.     }
  585.     private function popState(): void
  586.     {
  587.         if (0 === \count($this->states)) {
  588.             throw new \LogicException('Cannot pop state without a previous state.');
  589.         }
  591.         $this->state = array_pop($this->states);
  592.     }
  593. }