Call a function: Difference between revisions

=={{header|Kotlin}}==

In Kotlin parameters are always passed by value though, apart from the (unboxed) primitive types, the value passed is actually a reference to an object.

<lang scala>// version 1.0.6

fun fun1() = println("No arguments")

fun fun2(i: Int) = println("One argument = $i")

fun fun3(i: Int, j: Int = 0) = println("One required argument = $i, one optional argument = $j")

fun fun4(vararg v: Int) = println("Variable number of arguments = ${v.asList()}")

fun fun5(i: Int) = i * i

fun fun6(i: Int, f: (Int) -> Int) = f(i)

fun fun7(i: Int): Double = i / 2.0

fun fun8(x: String) = { y: String -> x + " " + y }

fun main(args: Array<String>) {

fun1() // no arguments

fun2(2) // fixed number of arguments, one here

fun3(3) // optional argument, default value used here

fun4(4, 5, 6) // variable number of arguments

fun3(j = 8, i = 7) // using named arguments, order unimportant

val b = false

if (b) fun1() else fun2(9) // statement context

println(1 + fun6(4, ::fun5) + 3) // first class context within an expression

println(fun5(5)) // obtaining return value

println(Math.round(2.5)) // no distinction between built-in and user-defined functions, though former usually have a receiver

fun1() // calling sub-routine which has a Unit return type by default

println(fun7(11)) // calling function with a return type of Double (here explicit but can be implicit)

println(fun8("Hello")("world")) // partial application isn't supported though you can do this

}</lang>

{{out}}

<pre>

No arguments

One argument = 2

One required argument = 3, one optional argument = 0

Variable number of arguments = [4, 5, 6]

One required argument = 7, one optional argument = 8

One argument = 9

20

25

3

No arguments

5.5

Hello world

</pre>