Question

我想知道为什么会这样。 finally和&也以这种方式行事。哪个其他Clojure符号有这种行为？为什么？

Answer 1

我相信你偶然发现了Clojure实施doc中影响&，catch和finally的错误。在当前的doc实现中，这三个被特别处理，并且关联的表达式似乎缺少语法引用。

以下是一个mod to doc，它添加了语法引用并且似乎按预期工作。此函数必须放在clojure.repl命名空间中。

(defmacro doc2
  [name]
  (if-let [special-name ('{& fn, catch try, finally, try} name)]
    `(#'print-doc (#'special-doc '~special-name))
    (cond
     (special-doc-map name) `(#'print-doc (#'special-doc '~name))
     (find-ns name) `(#'print-doc (#'namespace-doc (find-ns '~name)))
     (resolve name) `(#'print-doc (meta (var ~name))))))

(doc catch) =＆gt; {prints try doc并返回nil}

(doc2 catch) =＆gt; {prints try doc并返回nil}

(with-out-str (doc catch)) =＆gt; {打印try doc并返回""}

(with-out-str (doc2 catch)) =＆gt; "-------------------------\ntry\n (try expr* catch-clause* finally-clause?)\nSpecial Form\n catch-clause => (catch classname name expr*)\n finally-clause => (finally expr*)\n\n Catches and handles Java exceptions.\n\n Please see http://clojure.org/special_forms#try\n"

我会在Clojure bug追踪器上追逐它。

Clojure :( with-out-str（doc catch））返回“”

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