如何从另一个名称空间卸载函数？ [英] How to unload a function from another namespace?

问题描述

我从命名空间学习中加载了函数 say-hi

I load a function say-hi from namespace learning.greeting

(use 'learning.greeting)

当我尝试重新定义say-hi函数时在当前（用户）命名空间下，出现错误：

When I try to re-defn the say-hi function under the current (user) namespace, I got the error:

CompilerException java.lang.IllegalStateException: say-hi already refers to: #'learning.greeting/say-hi in namespace: user, compiling:(NO_SOURCE_PATH:1:1) 

那么如何从其他名称空间中卸载该函数？

So how to unload the function from other namespaces?

推荐答案

如果您希望摆脱REPL上另一个命名空间到Var的直接映射，请说

If you want to get rid of a direct mapping to a Var from another namespace at the REPL, say

(ns-unmap 'current-namespace 'local-alias)

示例：

user=> (ns-unmap *ns* 'reduce)
nil
user=> (reduce + 0 [1 2 3])
CompilerException java.lang.RuntimeException: Unable to resolve symbol: reduce in this context, compiling:(NO_SOURCE_PATH:2:1)

如果使用：rename ，本地别名将与Var的实际名称不同：

Local alias will differ from the actual name of the Var if :rename was used:

(use '[clojure.walk
       :only [keywordize-keys]
       :rename {keywordize-keys keywordize}])

要删除所有指向 clojure中的Vars的映射。步行：

(doseq [[sym v] (ns-map *ns*)]
  (if (and (var? v)
           (= (.. v -ns -name) 'clojure.walk))
    (ns-unmap *ns* sym)))

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