构建协议 Clojure 宏

Question

作为我的上一个问题的后续问题，我正在尝试编写一个构建 defprotocol: 的宏，

(build-protocol AProtocol
  [(a-method [this]) (b-method [this that])]
  (map (fn [name] `(~(symbol (str name "-method")) [~'this ~'that ~'the-other]))
    ["foo" "bar" "baz"])
  (map (fn [name] `(~(symbol (str name "-method")) [~'_]))
    ["hello" "goodbye"]))

应该扩展为

(defprotocol AProtocol
  (a-method [this])
  (b-method [this that])
  (foo-method [this that the-other])
  (bar-method [this that the-other])
  (baz-method [this that the-other])
  (hello-fn [_])
  (goodbye-fn [_]))

My attempts:

(defmacro build-protocol [name simple & complex]
  `(defprotocol ~name ~@simple
     ~@(loop [complex complex ret []]
         (if (seq complex)
           (recur (rest complex) (into ret (eval (first complex))))
           ret))))

并扩展 (macroexpand-1 '(...)):

(clojure.core/defprotocol AProtocol
  (a-method [this])
  (b-method [this that])
  (foo-method [this that the-other])
  (bar-method [this that the-other])
  (baz-method [this that the-other])
  (hello-method [_])
  (goodbye-method [_]))

我不是真的很高兴关于评估。另外，map 表达式非常难看。有更好的办法吗？欢迎任何和所有评论。

一旦我开始工作，我将为 (build-reify ...) 做一个类似的宏。我正在编写一个相当大的 Swing 应用程序，并且有几个组件（JButtons、JCheckBoxes 等），它们具有几乎相同的方法签名和操作。

Answer 1

我认为你这样做是颠倒了。首先指定“-method”内容，将其包装在某种容器中，以便构建协议知道什么是什么，并让它在宏内执行映射。例如：

(build-protocol AProtocol
  {[this that whatever] [foo bar baz],
   [_] [hello goodbye]}
  ; a-method and b-method...
)