code: function ($m) {
    var convert
    var key
    for (key in $m) {
      if ($m.hasOwnProperty(key) && $m[key] === true) {
        if (isDefine(convert)) convert += '.' + key
        else convert = key
      }
    }
    return convert
  }
docs: ($m → object{*})
  return string
  - convert modifiers object as string