The fn, ->, & return Keywords

04 / 09 / 25

Objective

The objectives of the fn, ->, and return keywords are to add rich function support to KSL.

Dictionary

fn - Keyword used to denote the start of a function.
-> - Keyword used to denote the return type/derivative of a function.
return - Keyword used to return a value from a function.

Examples

The fn keyword followed by a single identifier and parenthesis defines a basic function. Functions also need a defined return type, which can be set using the derive keyword (->.) Once you're done in your function body you can include a return keyword to return a value. It's expected that the returned value matches the type defined after derive. Technically speaking, the return keyword is optional, KSL will insert one for you automatically if it doesn't see one.

fn main(int a) -> float {
	return 10.0;
}

In the example above we can see a function defined, this function has the name main, it takes one integer parameter called a, and it returns a float. This function has the return statement defined in it's function body.

Functions can have multiple parameters separated by a comma. They cannot have multiple return types though.

fn main(int a, int b) -> int {
	return a + b;
}