public function analyze_php(string $file): array
  {
    $res = [];
    $php = file_get_contents($file);
    if ( $tmp = \Gettext\Translations::fromPhpCodeString($php, [
      'functions' => ['_' => 'gettext'],
      'file' => $file
      ]) ){
      foreach ( $tmp->getIterator() as $r => $tr ){
        $res[] = $tr->getOriginal();
      }
      $this->parser->mergeWith($tmp);
    }
    return array_unique($res);
  }