Callable for Swift

[migueldeicaza]

It would be nice to provide a Callable that can proxy directly to a Swift method, like the native C# binding does.

This is not currently possible with the Godot extension API, as this requires access to the CustomCallable
version of Callable which is just not exposed there.

[migueldeicaza]

This will be available in Godot 4.2

[migueldeicaza]

Work in progress: 398f0ee

The above should work, the next step would be to make a macro to allow for nice strongly typed values, rather than just forcing folks to accept a Variant array and returning an optional variant.