private function RouteCompiler::computeRegexp

Computes the regexp used to match a specific token. It can be static text or a subpattern.

Parameters

array $tokens The route tokens:

integer $index The index of the current token:

integer $firstOptional The index of the first optional token:

Return value

string The regexp pattern for a single token

File

drupal/core/vendor/symfony/routing/Symfony/Component/Routing/RouteCompiler.php, line 104

Class

RouteCompiler

RouteCompiler compiles Route instances to CompiledRoute instances.

Namespace

Code

private function computeRegexp(array $tokens, $index, $firstOptional) {
  $token = $tokens[$index];
  if ('text' === $token[0]) {

    // Text tokens
    return preg_quote($token[1], self::REGEX_DELIMITER);
  }
  else {

    // Variable tokens
    if (0 === $index && 0 === $firstOptional) {

      // When the only token is an optional variable token, the separator is required
      return sprintf('%s(?<%s>%s)?', preg_quote($token[1], self::REGEX_DELIMITER), $token[3], $token[2]);
    }
    else {
      $regexp = sprintf('%s(?<%s>%s)', preg_quote($token[1], self::REGEX_DELIMITER), $token[3], $token[2]);
      if ($index >= $firstOptional) {

        // Enclose each optional token in a subpattern to make it optional.
        // "?:" means it is non-capturing, i.e. the portion of the subject string that
        // matched the optional subpattern is not passed back.
        $regexp = "(?:{$regexp}";
        $nbTokens = count($tokens);
        if ($nbTokens - 1 == $index) {

          // Close the optional subpatterns
          $regexp .= str_repeat(")?", $nbTokens - $firstOptional - (0 === $firstOptional ? 1 : 0));
        }
      }
      return $regexp;
    }
  }
}