clojure - 导入 clojure.contrib.generic.math-functions

Question

我从 download site 下载了 clojure 1.2 和 clojure-contrib-1.2.0.jar .

我找到了关于 math functions 的信息.

如示例所示，我尝试运行代码。

(ns your-namespace
  (:require clojure.contrib.generic.math-functions))
(println (abs 10))

但是，当我按如下方式运行时，出现了以下错误。

CLOJURE_JAR=/Users/smcho/bin/jar/clojure.jar:/Users/smcho/bin/jar/clojure-contrib-1.2.0.jar
java -cp $CLOJURE_JAR:$CLASSPATH clojure.main SOURCE.CLJ

Exception in thread "main" java.lang.Exception: Unable to resolve symbol: abs in this context (hello.clj:4)    at clojure.lang.Compiler.analyze(Compiler.java:5205)        ...    at clojure.main.main(main.java:37)Caused by: java.lang.Exception: Unable to resolve symbol: abs in this context    at clojure.lang.Compiler.resolveIn(Compiler.java:5677)    at clojure.lang.Compiler.resolve(Compiler.java:5621)    at clojure.lang.Compiler.analyzeSymbol(Compiler.java:5584)    at clojure.lang.Compiler.analyze(Compiler.java:5172)    ... 25 more

可能出了什么问题？

Answer 1

尝试 :use 而不是 :require

(ns your-namespace
  (:use clojure.contrib.generic.math-functions))
(println (abs 10))
10
nil

Require 使符号(在本例中为 abs)可用，但您必须完全限定它。使用将符号导入“您的命名空间”:

(ns your-namespace2
  (:require clojure.contrib.generic.math-functions))
(println (clojure.contrib.generic.math-functions/abs 10))
10
nil