Getter & setter functions - allow extra "optional" parameters (i.e. parameters with default assignments)

[jon-heard]

Background

Currently, the getter / setter system requires that a getter function takes exactly 0 parameters and that a setter function takes exactly 1 parameter. If this is not adhered to then Godot errors with: Function "X" cannot be used as setter because of its signature..

If a getter or setter logically could or should take extra parameters, then the current solution is to write an alternative function with the same purpose, but taking those extra parameters.

Example - a solution that work with the current system

var length: float : get = get_length

func get_length() -> float:
    return length

func get_length_of_type(type: DistanceType = DistanceType.texture_pixels) -> void:
    match type:
        DistanceType.scaled:
            return length * scale
        DistanceType.screen:
            return length * scale * zoom
        _:
            return length

Proposal

My suggestion is to accept getter and setter functions that have more than the required number of parameters as long as the extra parameters are optional (i.e. they include a default assignment).

The benefit

If a getter / setter function logically could or should take extra parameters, then this proposal would allow it to, as long as the extra parameters have defaults that the getter / setter system can use. The advantage of this proposal is for more straightforward logic as it allows a having a single function for a single purpose rather than two functions for essentially the same purpose.

Example - a solution that takes advantage of this proposal

var length: float : get = get_length

func get_length(type: DistanceType = DistanceType.texture_pixels) -> void:
    match type:
        DistanceType.scaled:
            return length * scale
        DistanceType.screen:
            return length * scale * zoom
        _:
            return length

[jon-heard]

I have a few viewers responding with confusion faces. I'm curious as to where the confusion lies. Perhaps this is a polite way of saying that they don't think that this is a good idea, or a valuable modification? It'd be great to get some clarification so that I know how to proceed.

[dalexeev]

I'm not strictly against it, I just have doubts where it can be used.

Now you can work around it like this:

var my_var:
    get: return get_my_var()
    set(value): set_my_var(value)

func get_my_var(a = 1, b = 2):
    ...

func set_my_var(value, a = 1, b = 2):
    ...

[jon-heard]

It comes up now and again. One recent example:

I have a boolean "faded_black" variable to show/hide a ColorRect to blank the screen. The ColorRect has fading animations, played via the setter. However, sometimes I want to fade slowly (during the title) or fast (during some cutscenes). Currently, I have a "set_faded_black" function (the setter) and a "set_faded_black_custom_speed" function, which does the same thing, but with an extra "speed" parameter.

I think the technique you demonstrated is an improvement over the double-function technique I've been using. I'll adopt it.

I recognize that what I'm proposing has servicable workarounds. It's really just a convenience, I suppose.

[jon-heard]

Thanks for replying, btw.

[dalexeev]

See godotengine/godot#74144.

[dalexeev]

Let's close, since the behavior was identified as a bug (godotengine/godot#74144). Thanks for the contribution nonetheless!