对于解析classname感到困惑

Question

两个文件

types.clj:

(ns test.types)

(defrecord Price [date price])
(defrecord ProductPrice [name prices])

core.clj(没关系)

(ns test.core
  (:use [test.types])
  (:use [clojure.string :only (split)]))


(defn read-data [file]
  (let [name (subs (.getName file) 0 4)]
    (with-open [rdr (clojure.java.io/reader file)]
      (doall (map #(apply ->Price (split % #"\t")) (drop 2 (line-seq rdr)))))))

core.clj(java.lang.IllegalArgumentException:无法解析类名:ProductPrice)

(ns test.core
  (:use [test.types])
  (:use [clojure.string :only (split)]))


(defn read-data [file]
  (let [name (subs (.getName file) 0 4)]
    (with-open [rdr (clojure.java.io/reader file)]
      (ProductPrice. name (doall (map #(apply ->Price (split % #"\t")) (drop 2 (line-seq rdr))))))))

core.clj(没关系)

(ns test.core
  (:use [test.types])
  (:use [clojure.string :only (split)]))

(defrecord tProductPrice [name prices])
(defn read-data [file]
  (let [name (subs (.getName file) 0 4)]
    (with-open [rdr (clojure.java.io/reader file)]
      (tProductPrice. name (doall (map #(apply ->Price (split % #"\t")) (drop 2 (line-seq rdr)))))))

core.clj(java.lang.IllegalStateException: - > ProductPrice已经引用:#'test.types/ - > ProductPrice in namespace:test.core)

(ns test.core
  (:use [test.types])
  (:use [clojure.string :only (split)]))

(defrecord ProductPrice [name prices])
(defn read-data [file]
  (let [name (subs (.getName file) 0 4)]
    (with-open [rdr (clojure.java.io/reader file)]
      (ProductPrice. name (doall (map #(apply ->Price (split % #"\t")) (drop 2 (line-seq rdr)))))))

我对这些例外感到困惑.除了clojure.org和书籍中的一些最简单的例子之外,我找不到关于"记录"的更多用法.

任何帮助,非常感谢!

Answer 1

defrecord在以当前命名空间命名的包中创建一个java类.(ProductPrice....)是对该类型的构造函数的调用; 这是java interop - 不是普通的函数调用.

除非明确导入它或指定完整的包名,否则不能引用在java.lang之外定义的类或当前命名空间.这包括调用它的构造函数.

因此,要解决问题,您需要导入Price和ProductPrice.

 (ns test.core (:import [test.types Price]))
 (Price. ...)

或者调用完整的类+包名称:

 (test.types.Price. ...)