Question

我有一个文件“map_reduce2.clj”和另一个“map_reduce3.clj”，两个defin函数“map-reduce”自己。

现在我想在“map_reduce3.clj”中使用“map_reduce2.clj”的命名空间，但是当我在emacs中按“C-c C-k”来编译“map_reduce3.clj”时，

错误发生：“解析行已经引用：＃'chapter12.map-reduce2 / parse-line in namespace：chapter12.map-reduce3“，但这没有任何意义。

; map_reduce3.cli
(ns chapter12.map-reduce3
  (:use clojure.java.io)
  (:require [chapter12.map-reduce2 :as c12]))

(def IGNORE "_")

(defn parse-line [line]
  (let [tokens (.split (.toLowerCase line) " ")]
    [[IGNORE (count tokens)]]))

(defn average [numbers]
  (/ (apply + numbers)
     (count numbers)))

(defn reducer [combined]
  (average (val (first combined))))

(defn average-line-length [filename]
  (c12/map-reduce parse-line reducer (line-seq (reader filename))))


; map_reduce2.clj
(ns chapter12.map-reduce2
  (:use clojure.java.io))

(defn combine [mapped]
  (->> (apply concat mapped)
       (group-by first)
       (map (fn [[k v]]
              {k (map second v)}))
       (apply merge-with conj)))

(defn map-reduce [mapper reducer args-seq]
  (->> (map mapper args-seq)
       (combine)
       (reducer)))

(defn parse-line [line]
  (let [tokens (.split (.toLowerCase line) " ")]
    (map #(vector % 1) tokens)))

(defn sum [[k v]]
  {k (apply + v)})

(defn reduce-parsed-lines [collected-values]
  (apply merge (map sum collected-values)))


(defn word-frequency [filename]
  (map-reduce parse-line reduce-parsed-lines (line-seq (reader filename))))

images of the the error

Answer 1

这可能意味着您有脏REPL状态。也许你将函数parse-line从一个名称空间移动到另一个名称空间。我建议重新启动REPL，或从parse-line How to unload a function from another namespace?卸载map-reduce3。

clojure不能在不同的命名空间中定义相同的功能？不可能

1 个答案: