Where to Implement AppLabel

[zicklag]

I was going to work on using labels instead of indices for sub-apps for the new pipelined renderer, but I wanted some guidance on where we wanted the label code implemented. Currently all of our labels are trapped in the bevy_ecs crate, and their derive macros are in bevy_ecs_macros, but if we need an AppLabel type, then it kind of makes most sense to put it in the bevy_app crate.

In that case I think we would need a new bevy_app_macros crate, and we would end up copying the label creation and derive code from the bevy_ecs crate. Is that the direction we want to take? It seems like it would be nice not to have to duplicate the code, but it seems weird to shove the AppLabel inside of bevy_ecs where it isn't used.

If we wanted to avoid some extra code duplication we could create a new bevy_label crate that has the shared code for the traits and macros, but I don't know if we want to add yet another crate just for that.

[TheRawMeatball]

I think putting the majority of the code for implementing labels in a separate crate, or perhaps bevy_utils would be the correct choice

[cart]

Yeah I think generic label code should probably live in bevy_utils for now.