如何在 Clojure 中从字符串定义函数？
我想这样做（在 REPL 或任何地方）
(defn (symbol "print-string") [k] (println k))
，然后能够做到
(print-string "lol")
或者，如果有任何其他方法可以从宏中的自定义字符串创建 defn，您能否将我推向正确的方向？
I'd like to do this (in REPL or anywhere)
(defn (symbol "print-string") [k] (println k))
and then be able to do
(print-string "lol")
Or, if there is any other way to create defn from custom strings in macroses, could you push me into the right direction please?
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评论（4）
dnolen 的解决方案在宏展开时工作，而 Brian Carper 的解决方案在读取时工作。 现在，这是运行时的：
dnolen's solution works at macro expansion time, Brian Carper's at read-time. Now, here's one for run-time:
我更喜欢 dnolen 的答案，但你也可以这样做：
#=()在读取时进行评估。 我不知道 Clojure 的这个功能有多稳定，我不会依赖它在未来不会改变。 宏就是我的做法。I like dnolen's answer better, but you can do this too:
#=()is evaluated at read-time. I don't know how stable a feature of Clojure this is, I wouldn't rely on it not to change in the future. Macros are how I'd do it.仅供参考 - dnolen 的答案仅适用于文字字符串，不适用于 def'd 或 let'd 变量中的字符串。
（defmacro defn-with-str [字符串参数和正文]
`(defn ~(符号字符串) ~args ~@body))
(def hisym "hi")
(defn-with-str hisym [] (println "hi"))
的函数
您现在有一个名为“hisym” (hi) -> java.lang.Exception：无法解析符号：在此上下文中 hi (NO_SOURCE_FILE:6)
（hisym）-> 打印“hi”
要避免这种情况，请评估宏
中的函数名称字符串
（defmacro defn-with-str [字符串参数和正文]
`(defn ~(符号(评估字符串)) ~args ~@body))
FYI - dnolen's answer will only work for literal strings, and not for strings in def'd or let'd variables.
(defmacro defn-with-str [string args & body]
`(defn ~(symbol string) ~args ~@body))
(def hisym "hi")
(defn-with-str hisym [] (println "hi"))
You now have a function called "hisym"
(hi) -> java.lang.Exception: Unable to resolve symbol: hi in this context (NO_SOURCE_FILE:6)
(hisym) -> prints "hi"
To avoid this, eval the function name string in the macro
(defmacro defn-with-str [string args & body]
`(defn ~(symbol (eval string)) ~args ~@body))