在 Clojure 中嵌套宏

Question

考虑这个伪代码：

(defrc name
  "string"
    [a :A]
    [:div a])

其中 defrc 是一个宏，将扩展为以下内容

(let [a (rum/react (atom :A))]
  (rum/defc name < rum/reactive []
    [:div a]))

其中rum/defc本身就是一个宏。我想出了下面的代码：

(defmacro defrc
          [name subj bindings & body]
          (let [map-bindings# (apply array-map bindings)
                keys# (keys map-bindings#)
                vals# (vals map-bindings#)
                atomised-vals# (atom-map vals#)]
               `(let ~(vec (interleave keys# (map (fn [v] (list 'rum/react v)) (vals atomised-vals#))))
                     (rum/defc ~name < rum/reactive [] ~@body))))

几乎可行：

(macroexpand-all '(defrc aname
       #_=>   "string"
       #_=>   [a :A]
       #_=>   [:div a]))
(let* [a (rum/react #object[clojure.lang.Atom 0x727ed2e6 {:status :ready, :val nil}])] (rum/defc aname clojure.core/< rum/reactive [] [:div a]))

然而，当使用它时会导致语法错误：

ERROR: Syntax error at (clojure.core/< rum.core/reactive [] [:div a])

这是不是内部宏没有展开？

Answer 1

事实证明宏工作正常，但出现问题是因为 < 位于语法引号内，它被扩展为 clojure.core/<，而 Rum 只是从 Rum 的源代码中查找引用的 <，相关片段：

...(cond
        (and (empty? res) (symbol? x))
          (recur {:name x} next nil)
        (fn-body? xs)        (assoc res :bodies (list xs))
        (every? fn-body? xs) (assoc res :bodies xs)
        (string? x)          (recur (assoc res :doc x) next nil)
        (= '< x)             (recur res next :mixins)
        (= mode :mixins)
          (recur (update-in res [:mixins] (fnil conj []) x) next :mixins)
        :else
          (throw (IllegalArgumentException. (str "Syntax error at " xs))))...

在 Clojure 中嵌套宏

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