Review

class PeepholeSubstituteAlternateSyntax {
  /**
   * Checks if it is safe to fold Array() constructor into []. It can be
   * obviously done, if the initial constructor has either no arguments or
   * at least two. The remaining case may be unsafe since Array(number)
   * actually reserves memory for an empty array which contains number elements.
   */
  private FoldArrayAction isSafeToFoldArrayConstructor(Node arg) {
    FoldArrayAction action = FoldArrayAction.NOT_SAFE_TO_FOLD;

    if (arg == null) {
      action = FoldArrayAction.SAFE_TO_FOLD_WITHOUT_ARGS;
    } else if (arg.getNext() != null) {
      action = FoldArrayAction.SAFE_TO_FOLD_WITH_ARGS;
    } else {
      switch (arg.getType()) {
        case (Token.STRING):
          // "Array('a')" --> "['a']"
          action = FoldArrayAction.SAFE_TO_FOLD_WITH_ARGS;
          break;
        case (Token.NUMBER):
          // "Array(0)" --> "[]"
          if (arg.getDouble() == 0) {
            action = FoldArrayAction.SAFE_TO_FOLD_WITHOUT_ARGS;
          }
          break;
        case (Token.ARRAYLIT):
          // "Array([args])" --> "[[args]]"
          action = FoldArrayAction.SAFE_TO_FOLD_WITH_ARGS;
          break;
        default:
      }
    }
    return action;
  }

}