Currying

Currying transforms a function that takes multiple arguments and returns it as a chain of functions.

import org.funktionale.currying.*

val sum2ints = {(x: Int, y: Int)-> x + y }
val curried:(Int) -> (Int) -> Int = sum2ints.curried()
assertEquals(curried(2)(4), 6)
val add5 = curried(5)
assertEquals(add5(7), 12)

Also you could uncurry functions:

val sum2ints: (Int, Int) -> Int = { x, y -> x + y }
val curried: (Int) -> (Int) -> Int = sum2ints.curried()
assertEquals(curried(2)(4), 6)
//same type as sum2ints,
assertEquals(curried.uncurried()(2, 4), 6)
assertEquals(sum2ints(2, 4), 6)

val sum3ints: (Int, Int, Int) -> Int = { x, y, z -> x + y }
val f: (Int) -> (Int) -> (Int) -> Int =sum3ints.curried()
val x: (Int, Int, Int) -> Int =f.uncurried()