nikic / PHP-Parser

        // if it starts with 0 it's one of the special integer notations

        if ('0' === $str[0]) {

            // hex

            if ('x' === $str[1] || 'X' === $str[1]) {

                return hexdec($str);

            }

            // bin

            if ('b' === $str[1] || 'B' === $str[1]) {

        // if first char is 0 (and number isn't 0) it's a special syntax

        if ('0' === $str[0]) {

            // hex

            if ('x' === $str[1] || 'X' === $str[1]) {

                return hexdec($str);

            }

            // bin

            if ('b' === $str[1] || 'B' === $str[1]) {

                if (isset(self::$replacements[$str])) {

                    return self::$replacements[$str];

                } elseif ('x' === $str[0] || 'X' === $str[0]) {

                    return chr(hexdec($str));

                } elseif ('u' === $str[0]) {

                    return self::codePointToUtf8(hexdec($matches[2]));

                } else {

                    return chr(octdec($str));