Clojure 类型提示，无法解析类名 clojure.core$double

Question

我有以下代码，但是当尝试对最终规范化函数进行类型提示时，编译器抱怨：无法解析类名：clojure.core$double.

我看不出未在平方和或 vec-length 中完成的归一化函数有何不同。

谢谢。

(defn ^double sum-of-squares
  "Given a vector v, compute the sum of the squares of elements."
  [^doubles v]
  (r/fold + (r/map #(* % %) v)))

(defn ^double vec-length
  "Compute the length of vector v."
  [^doubles v]
  (Math/sqrt (sum-of-squares v)))

(defn ^doubles normalize
  "Compute the unit vector (normalize) v."
  [^doubles v]
  (let [l (vec-length v)]
    (into [] (r/map #(/ % l) v))))

Answer 1

return 值的类型提示必须放在参数向量之前而不是名称之前。

http://clojure.org/java_interop#Java%20Interop-Type%20Hints

您的第一个定义应该如下所示

(defn sum-of-squares
  "Given a vector v, compute the sum of the squares of elements."
  (^double [^doubles v]
    (r/fold + (r/map #(* % %) v))))

Clojure 类型提示，无法解析类名 clojure.core$double

Clojure type hinting, Cannot resolve classname clojure.core$double

clojure

type-hinting