对于解析classname感到困惑

时间:2012-04-04 05:32:07

标签: clojure

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 / - >名称空间中的ProductPrice: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)))))))

我对这些异常感到困惑。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!

1 个答案:

答案 0 :(得分:9)

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 - 不是简单的函数调用。

除非明确导入或指定完整的包名,否则不能引用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,要解决此问题,您需要导入Price和ProductPrice。

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

或调用完整的类+包名称:

 (test.types.Price. ...)