Functions

Named functions

Functions are used for encapsulating specific behavior in a program te be reused with given parameters. Functions are described by the fun keyword. They return a value with the return keyword which takes an expression as right-hand. Everything after a return is considered unreachable code.

To specify the returned type of a function a semicolon (:) is written after the fun keyword. After this a identifier is required to set the name of the function. Functions can receive parameters via parentheses (( and )). Parameters are declared inside separated by a comma (,). Parameters require a type specification using a semicolon (:) followed by the type.

A function needs a body with the statements that execute when the function is called. Function bodies are declared by placing an opening curly brace ({) to start, and an closing curly brace (}) to end it. A function with a specified return type must always return the given type. Functions without return types may use the return keyword to end early.

EBNF Notation

name = "a".."z" | "A".."Z" , { "a".."z" | "A".."Z" | "0".."9" } ;
function = "fun" , [ ":", name ] , name , [ "(" , [ name , ":" , name , "," ] , { name , ":" , name } ")" ] , "{" { statement } , "}" ;

_{See statements for details about statements.}

Example

fun foo {
    // Do somthing
}

fun bar(parameter: string) {
    // Do somthing
}

fun baz(firstName: string, lastName: string) {
   // Do somthing
}

fun: string qux {
   return 'value'
}

fun: string quux(parameter: string) {
   parameter = 'Hello' + parameter
   return parameter
}

fun: string quuz(firstName: string, lastName: string) {
   val greet = 'Hello' + firstName + lastName
   return greet
}