如何在scala中创建curried匿名函数？

Question

如何在Scala中创建匿名和curried功能？以下两个失败:

scala> (x:Int)(y:Int) => x*y
<console>:1: error: not a legal formal parameter
       (x:Int)(y:Int) => x*y
              ^

scala> ((x:Int)(y:Int)) => x*y
<console>:1: error: not a legal formal parameter
       ((x:Int)(y:Int)) => x*y
               ^

Answer 1

要创建一个curried函数,请将其写为多个函数(实际上就是这种情况;-)).

scala> (x: Int) => (y: Int) => x*y
res2: Int => Int => Int = <function1>

这意味着你有一个从Int到Int到Int的函数的函数.

scala> res2(3)
res3: Int => Int = <function1>

或者你可以像这样写:

scala> val f: Int => Int => Int = x => y => x*y
f: Int => Int => Int = <function1>