Question

我正在寻找有关Clojure中类型提示范围的信息，例如，如果我写的话

(defn big-add [^BigInteger x y] (.add x y))

与

相同

(defn big-add [^BigInteger x ^BigInteger y] (.add x y))

？假设我写了

(defn big-sum 
  ([] BigInteger/ZERO)
  ([^BigInteger x] x)
  ([^BigInteger x & more] (.add x (apply big-sum more) )))

Clojure是否认为more已满BigInteger？假设我不想告诉它？我会做点什么吗

(defn foo [^BigInteger x & ^Long more] ...)

？

Answer 1

只需将 warn-on-reflection 设置为true，然后使用无法解析类型的函数测试表达式。

REPL：

(set! *warn-on-reflection* true)
(defn testo [s]
      (str s))
=> #'user/testo

(defn testo [s]
      (.charAt s 1))
=> Reflection warning, NO_SOURCE_PATH:2:8 - call to charAt can't be resolved.

(defn testo [^java.lang.String s]
      (.charAt s 1))
=> #'user/testo

(defn testo [^java.lang.String s s2]
      (.charAt s2 1))
=> Reflection warning, NO_SOURCE_PATH:2:8 - call to charAt can't be resolved.

(defn testo [^java.lang.String s & more]
      (.charAt (first more) 1))
=> Reflection warning, NO_SOURCE_PATH:2:8 - call to charAt can't be resolved.

最后

(defn testo [s & ^java.lang.String more]
      (.charAt (first more) 1))
=> CompilerException java.lang.RuntimeException: & arg cannot have type hint, compiling:(NO_SOURCE_PATH:1:1)

对每个问题的简短回答都是:(

Clojure中的类型提示范围？

1 个答案: