通过委派现有功能来实现协议 [英] Implementing a protocol by delegating to existing functions

问题描述

我正在通过模拟棋盘游戏来学习Elixir，并且我有以下代码：

I'm learning Elixir by modeling a board game, and I have this code:

defprotocol Board do
  def can_handle_move(self)
  def handle_move(self, move)
end

defimpl Board, for: List do
  def can_handle_move(self), do: Enum.empty?(self)
  def handle_move(self, move), do: List.delete(self, move)
end

实现看起来确实更复杂。实际上， can_handle_move 只是 Enum.empty？和 handle_move 只是 List.delete 。 Elixir有办法表达这一点吗？例如：

The implementation looks more complicated that it really is. Actually, can_handle_move is just Enum.empty? and handle_move is just List.delete. Does Elixir have a way of expressing this? Something like:

defimpl Board, for: List do
  def can_handle_move = &Enum.empty?/1
  def handle_move = &List.delete/2
end

...不会编译。我也尝试过不使用 def s。

...which doesn't compile. I've also tried without the defs.

推荐答案

尝试 Kernel＃defdelegate / 2 。

defimpl Board, for: List do
  defdelegate can_handle_move(self), to: Enum, as: :empty?
  defdelegate handle_move(self, move), to: List, as: :delete
end

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