b8072864aa
# Objective Three impls are generated for each of these traits when the `reflect_functions` feature is enabled. Helps with #19873. ## Solution Two of the three (the `&T` and `&mut T` ones) can be avoided by instead providing blanket impls. The impl for `T` remains. ## Testing I checked the output via `cargo expand`. According to `-Zmacro-stats`, the size of the `Reflect` code generate for `bevy_ui` drops by 10.4%.
93 lines
2.5 KiB
Rust
93 lines
2.5 KiB
Rust
/// Helper macro to implement the necessary traits for function reflection.
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///
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/// This macro calls the following macros:
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/// - [`impl_get_ownership`](crate::func::args::impl_get_ownership)
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/// - [`impl_from_arg`](crate::func::args::impl_from_arg)
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/// - [`impl_into_return`](crate::func::impl_into_return)
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///
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/// # Syntax
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///
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/// For non-generic types, the macro simply expects the type:
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///
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/// ```ignore
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/// impl_function_traits!(foo::bar::Baz);
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/// ```
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///
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/// For generic types, however, the generic type parameters must also be given in angle brackets (`<` and `>`):
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///
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/// ```ignore
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/// impl_function_traits!(foo::bar::Baz<T, U>; <T: Clone, U>);
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/// ```
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///
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/// For generic const parameters, they must be given in square brackets (`[` and `]`):
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///
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/// ```ignore
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/// impl_function_traits!(foo::bar::Baz<T, N>; <T> [const N: usize]);
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/// ```
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macro_rules! impl_function_traits {
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(
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$ty: ty
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$(;
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< $($T: ident $(: $T1: tt $(+ $T2: tt)*)?),* >
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)?
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$(
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[ $(const $N: ident : $size: ident),* ]
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)?
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$(
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where $($U: ty $(: $U1: tt $(+ $U2: tt)*)?),*
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)?
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) => {
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$crate::func::args::impl_get_ownership!(
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$ty
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$(;
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< $($T $(: $T1 $(+ $T2)*)?),* >
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)?
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$(
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[ $(const $N : $size),* ]
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)?
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$(
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where $($U $(: $U1 $(+ $U2)*)?),*
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)?
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);
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$crate::func::args::impl_from_arg!(
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$ty
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$(;
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< $($T $(: $T1 $(+ $T2)*)?),* >
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)?
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$(
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[ $(const $N : $size),* ]
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)?
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$(
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where $($U $(: $U1 $(+ $U2)*)?),*
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)?
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);
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$crate::func::impl_into_return!(
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$ty
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$(;
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< $($T $(: $T1 $(+ $T2)*)?),* >
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)?
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$(
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[ $(const $N : $size),* ]
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)?
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$(
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where $($U $(: $U1 $(+ $U2)*)?),*
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)?
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);
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};
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}
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pub(crate) use impl_function_traits;
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/// Helper macro that returns the number of tokens it receives.
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///
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/// See [here] for details.
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///
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/// [here]: https://veykril.github.io/tlborm/decl-macros/building-blocks/counting.html#bit-twiddling
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macro_rules! count_tokens {
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() => { 0 };
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($odd:tt $($a:tt $b:tt)*) => { ($crate::func::macros::count_tokens!($($a)*) << 1) | 1 };
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($($a:tt $even:tt)*) => { $crate::func::macros::count_tokens!($($a)*) << 1 };
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}
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pub(crate) use count_tokens;
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