Bitsets implement Default

[mio991]

Adds a Default implementation for Enums.

This came about because I wanted to use ArrayMesh::add_surface_from_arrays with SurfaceTool::commit_to_arrays but had no idea which ArrayFormat to use. In the docs the default value is 0.

[Bromeon]

Thanks! This was already suggested in #101 (comment), but there are a few problems with a Default implementation for enums:

1. The value 0 does not necessarily represent a valid enumerator.
   • Example FileAccess::ModeFlags doesn't have one with value 0.
2. If 0 is valid, it may not be the most "obvious" choice for a default. Enumerators may be ordered systematically, not by usage frequency.
   • Example: GDExtension::InitializationLevel has CORE as 0, but typically used is SCENE.
3. 0 assigned to multiple enumerators -- this will play a role when using the string repr.
   • Example: CameraServer::FeedImage has FEED_RGBA_IMAGE, FEED_YCBCR_IMAGE, FEED_Y_IMAGE with value 0

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It also seems like it wouldn't solve the problem you have here.

This came about because I wanted to use ArrayMesh::add_surface_from_arrays with SurfaceTool::commit_to_arrays but had no idea which ArrayFormat to use. In the docs the default value is 0.

Enum::default() may not be the same value as the default parameter's value.

What you're looking for here is an implementation of default parameters rather than enum defaults. There has been some discussion over at gdnative: godot-rust/gdnative#814

[mio991]

Changed it so that only Bitsets implement Default.

[Bromeon]

Looks good! For now, I think default() is a good enabler, although in the future I might consider adding something like an ALL_UNSET constant or so instead.

Just a small comment, then should be good to go 🙂

bors try

[Bromeon]

collect() should not be necessary, I think the expression inside quote! can also work on an iterator.

[bors]

try

Build succeeded:

• full-ci

[Bromeon]

Thanks!
bors r+

[bors]

Build succeeded:

• full-ci