Add some(), every() and reduce_right() methods to Array

[ghost]

Describe the project you are working on

None yet, I'm still learning Godot.

Describe the problem or limitation you are having in your project

None.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

Simple Array methods based on JavaScript Array (developer.mozilla.org).

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

reduce_right:

var a = [[0, 1], [2, 3], [4, 5]].reduce_right(
    func(accumulator, current_value) : accumulator + current_value, [])

# a = [4, 5, 2, 3, 0, 1]

some:

[5, 10, 0].some(func(v): v > 5) # true
[5, 5 , 0].some(func(v): v > 5) # false

every:

[6, 10, 6].every(func(v): v > 5) # true
[6, 10, 0].every(func(v): v > 5) # false

If this enhancement will not be used often, can it be worked around with a few lines of script?

How it looks with a workaround:

var ArrayHelpers = preload("res://gd-libs/array-helpers/lib.gd")

func reduce_right(array: Array, reduce_fn: Callable, initial_value = 0):
    return ArrayHelpers.reduce_right(array, reduce_fn, initial_value)

var r = reduce_right ( [[10], [5, 2], [1, 3]], func(a, v): a + v )

Is there a reason why this should be core and not an add-on in the asset library?

It's simple enough to not be built-in. The PR godotengine/godot#38645 added filter/map/reduce.

I can't do PR due to the repository weight.

[KoBeWi]

reduce() exists in 4.0. You can achieve reduce_right() by reversing the array before using it.

Instead of some(), we could just add find_custom() method (bsearch_custom() doesn't work for unsorted arrays) and every() is the same as some() with opposite condition.

[Calinou]

While you can use array.filter(...).size() >= 1 and array.filter(...).size() == array.size(), I like the syntactic sugar aspect of some() and every(). some() and every() can also bail out early, which improves performance with large arrays.

reduce_right() avoids having to reverse the array before reducing it (which has a performance cost for large arrays), but I think concrete use cases for it are few and far between.

[nathanfranke]

I think reduce_right it too oddly specific to have its own method. I think invert().reduce() would be more readable, and if performance is important, just use a for loop.

[Calinou]

Instead of some(), we could just add find_custom() method (bsearch_custom() doesn't work for unsorted arrays) and every() is the same as some() with opposite condition.

This was requested in #1120, but I think it should be addressed in a separate pull request.