Phlexy\LexerDataGenerator::getNumberOfCapturingGroupsInRegex PHP Method

    protected function getNumberOfCapturingGroupsInRegex($regex)
    {
        // The regex to count the number of capturing groups should be fairly complete. The only thing I know it
        // won't work with are (?| ... ) groups.
        return preg_match_all('~
                (?:
                    \\(\\?\\(
                  | \\[ [^\\]\\\\]* (?: \\\\ . [^\\]\\\\]* )* \\]
                  | \\\\ .
                ) (*SKIP)(*FAIL) |
                \\(
                (?!
                    \\?
                    (?!
                        <(?![!=])
                      | P<
                      | \'
                    )
                  | \\*
                )
            ~x', $regex, $dummyVar);
    }