Data commit

Task/Call-a-function/Kotlin/call-a-function.kotlin

@@ -0,0 +1,31 @@
+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() {
+    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(kotlin.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
+}