5.2.3. Functions

Spicy’s language allows to define custom functions just like most other languages. The generic syntax for defining a function with is N parameters is:

[public] function NAME(NAME_1: TYPE_1, ..., NAME_N: TYPE_N) [: RETURN_TYPE ] {
    ... BODY ...
}

A public function will be accessible from other modules . If the return type is skipped, it’s implicitly taken as void, i.e., the function will not return anything. If a function has return type other than void, all paths through the body must end in a return returning a corresponding value.

A parameter specification can be postfixed with a default value: NAME: TYPE = DEFAULT. Callers may then omit that parameter.

By default, by parameters are passed by constant reference and hence remain read-only inside the function’s body. To make a parameter modifiable, with any changes becoming visible to the caller, a parameter can be prefixed with inout:

module Test;

global s = "1";

function foo(inout x: string) {
    x = "2";
}

print s;
foo(s);
print s;

1
2

Spicy has couple more function-like constructs (Unit Hooks and Unit Parameters) that use the same conventions for parameter passing.