User-created functions

scale-percent-function.gpc

int output;

main {
    output = scale_percent(get_ival(PS5_RX), 125);
    set_val(PS5_RX, output);
}

function scale_percent(value, percent) {
    return (value * percent) / 100;
}

Rules:

• Declare with function name(parameter, ...) { ... }.

• Parameters are optional: function reset_mode() { ... } is valid.

• Parameters are local integer values.

• Global runtime variables remain accessible.

• A reached return expression; immediately exits.

• If no return is reached, the result is 0.

• Do not mix valued returns and bare returns.

• Recursion compiles with a warning because worst-case stack use cannot be proven; avoid it in real-time scripts.

• A user-created function's return value may be ignored. The unused-return compiler error applies to built-ins whose return value is marked as required, not to user functions.

A parameterless function used only for its side effect can be called as a statement:

reset-mode-function.gpc

int mode;

main {
    if(event_press(PS5_CIRCLE)) {
        reset_mode();
    }
}

function reset_mode() {
    mode = 0;
}

Functions make repeated logic readable, but deep call chains and large expressions increase stack pressure.