Composing functions in Kotlin

compose.kt

fun compose<T>( fa: ( T ) -> T, fb : ( T ) -> T ) : ( T ) -> T {
  return { ( a : T ) : T -> fb( fa( a ) ) }
}

fun main( args : Array<String> ) {
  val composed = compose<Int>( { ( a : Int ) : Int -> a + 10 },  // add 10
                               { ( a : Int ) : Int -> a * 2  } ) // multiply by 2
  println( composed( 2 ) )  // prints 24
}

Is the Function1 extension for function compose still needed or has it become part of the standard library?

It should be part of the standard library if its not already.