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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 :ref:`accessible from other modules <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 :ref:`statement_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:

.. spicy-code:: function-inout.spicy

    module Test;

    global s = "1";

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

    print s;
    foo(s);
    print s;


.. spicy-output:: function-inout.spicy
    :exec: spicyc -j %INPUT

Spicy has couple more function-like constructs (:ref:`unit_hooks` and :ref:`unit_parameters`) that use the same conventions for parameter passing.