protected function checkGems() { if (self::$check_gems_result === null) { self::$check_gems_result = true; foreach (self::$required_gems[self::$sass_version] as $gem => $version) { if (!$version) { $version = ">= 0"; } if ($error = Rubygems::require_gem($gem, $version)) { self::$check_gems_result = $error; } } } return self::$check_gems_result; }