Kotlin Standard Library Cookbook

Getting ready

To understand the concept of function currying, let's consider the following example of a function handling three parameters:

fun foo(a: A, b: B, c: C): D 

Its curried form would look like this:

fun carriedFoo(a: A): (B) -> (C) -> D 

In other words, the curried form of the foo function would take a single argument of the A type and return another function of the following type: (B) -> (C) -> D. The returned function is responsible for handling the second argument of the original function and returns another function, which takes the third argument and returns a value of type D. 

In the next section, we are going to implement the curried() extension function for the generic functional type declared as follows:  ...