Move Name from bevy_core to bevy_ecs

[CAD97]

Objective

• Part of breaking bevy_core up into more specific locations.
• Name is universally applicable to ecs consumers, so should be available in bevy_ecs.

Solution

• Move Name from bevy_core to bevy_ecs.
• Name utilizes #[derive(Component)]; use extern crate self as bevy_ecs to make the expected name available.

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Changelog

Changed

• The Name struct moved from bevy::core to bevy::ecs.

Migration Guide

• If you're using a bevy::prelude import, no migration is necessary.
• If you aren't, replace uses of bevy::core::Name with bevy::ecs::Name.

[cart]

Name is a pretty opinionated component. It prehashes strings, uses a "fast compare" based on that, and uses a Cow internally. It is also a "generic" Name type, which outside the context of a general purpose engine / scene system (or games with some use for a generic Name construct) probably isn't advisable.

At least for me, merging this would be motivated largely by a desire to remove bevy_core and less by a conviction that bevy_ecs is the place for it.

Given that for Bevy, this is intended to be used for editor / scene scenarios, I think bevy_scene might be the better place for it. It exists "higher up" in the stack and I think that wouldn't require changing our dependency graph at all.

[CAD97]

Makes sense! I'll retool this to move it to bevy_scene later then.