src/CallbackRoute.php
protected function getPatternRegex($pattern) {
        $result = preg_replace_callback('`{([^}]+)}`i', function ($match) {
            if (preg_match('`(.*?)([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)(.*?)`', $match[1], $matches)) {
                $before = preg_quote($matches[1], '`');
                $param = $matches[2];
                $after = preg_quote($matches[3], '`');
            } else {
                throw new \Exception("Invalid route parameter: $match[1].", 500);
            }

            $param_pattern = val($param, $this->conditions, val($param, self::$globalConditions, '[^/]+?'));
            $result = "(?<$param>$before{$param_pattern}$after)";

            return $result;
        }, $pattern);

        $result = '`^'.$result.'$`i';
        return $result;
    }
protected function getPatternRegex($pattern) {
        $result = preg_replace_callback('`{([^}]+)}`i', function ($match) {
            if (preg_match('`(.*?)([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)(.*?)`', $match[1], $matches)) {
                $before = preg_quote($matches[1], '`');
                $param = $matches[2];
                $after = preg_quote($matches[3], '`');
            } else {
                throw new \Exception("Invalid route parameter: $match[1].", 500);
            }

            $param_pattern = val($param, $this->conditions, val($param, self::$globalConditions, '[^/]+?'));
            $result = "(?<$param>$before{$param_pattern}$after)";

            return $result;
        }, $pattern);

        $result = '`^'.$result.'$`i';
        return $result;
    }
Convert a path pattern into its regex.

@param string $pattern The route pattern to convert into a regular expression.
@return string Returns the regex pattern for the route.