Question

How can I create an anonymous and curried function in Scala? The following two failed:

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

To create a curried function write it as if it were multiple functions (that’s actually the case 😉 ).

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

This means you have a function from Int to a function from Int to Int.

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

alternatively you can write it like this:

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