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# Objective Closes #7622. I was working on adding support for reflecting generic functions and found that I wanted to use an argument's `TypeId` for hashing and comparison, but its `TypePath` for debugging and error messaging. While I could just keep them separate, place them in a tuple or a local struct or something, I think I see an opportunity to make a dedicate type for this. Additionally, we can use this type to clean up some duplication amongst the type info structs in a manner similar to #7622. ## Solution Added the `Type` type. This should be seen as the most basic representation of a type apart from `TypeId`. It stores both the `TypeId` of the type as well as its `TypePathTable`. The `Hash` and `PartialEq` implementations rely on the `TypeId`, while the `Debug` implementation relies on the `TypePath`. This makes it especially useful as a key in a `HashMap` since we get the speed of the `TypeId` hashing/comparisons with the readability of `TypePath`. With this type, we're able to reduce the duplication across the type info structs by removing individual fields for `TypeId` and `TypePathTable`, replacing them with a single `Type` field. Similarly, we can remove many duplicate methods and replace it with a macro that delegates to the stored `Type`. ### Caveats It should be noted that this type is currently 3x larger than `TypeId`. On my machine, it's 48 bytes compared to `TypeId`'s 16. While this doesn't matter for `TypeInfo` since it would contain that data regardless, it is something to keep in mind when using elsewhere. ## Testing All tests should pass as normal: ``` cargo test --package bevy_reflect ``` --- ## Showcase `bevy_reflect` now exports a `Type` struct. This type contains both the `TypeId` and the `TypePathTable` of the given type, allowing it to be used like `TypeId` but have the debuggability of `TypePath`. ```rust // We can create this for any type implementing `TypePath`: let ty = Type::of::<String>(); // It has `Hash` and `Eq` impls powered by `TypeId`, making it useful for maps: let mut map = HashMap::<Type, i32>::new(); map.insert(ty, 25); // And it has a human-readable `Debug` representation: let debug = format!("{:?}", map); assert_eq!(debug, "{alloc::string::String: 25}"); ``` ## Migration Guide Certain type info structs now only return their item types as `Type` instead of exposing direct methods on them. The following methods have been removed: - `ArrayInfo::item_type_path_table` - `ArrayInfo::item_type_id` - `ArrayInfo::item_is` - `ListInfo::item_type_path_table` - `ListInfo::item_type_id` - `ListInfo::item_is` - `SetInfo::value_type_path_table` - `SetInfo::value_type_id` - `SetInfo::value_is` - `MapInfo::key_type_path_table` - `MapInfo::key_type_id` - `MapInfo::key_is` - `MapInfo::value_type_path_table` - `MapInfo::value_type_id` - `MapInfo::value_is` Instead, access the `Type` directly using one of the new methods: - `ArrayInfo::item_ty` - `ListInfo::item_ty` - `SetInfo::value_ty` - `MapInfo::key_ty` - `MapInfo::value_ty` For example: ```rust // BEFORE let type_id = array_info.item_type_id(); // AFTER let type_id = array_info.item_ty().id(); ``` |
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| .. | ||
| dynamic_enum.rs | ||
| enum_trait.rs | ||
| helpers.rs | ||
| mod.rs | ||
| variants.rs | ||