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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-18 02:49:50 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-18 02:49:50 +0000 |
commit | 9835e2ae736235810b4ea1c162ca5e65c547e770 (patch) | |
tree | 3fcebf40ed70e581d776a8a4c65923e8ec20e026 /vendor/partial_ref/src/macros.rs | |
parent | Releasing progress-linux version 1.70.0+dfsg2-1~progress7.99u1. (diff) | |
download | rustc-9835e2ae736235810b4ea1c162ca5e65c547e770.tar.xz rustc-9835e2ae736235810b4ea1c162ca5e65c547e770.zip |
Merging upstream version 1.71.1+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'vendor/partial_ref/src/macros.rs')
-rw-r--r-- | vendor/partial_ref/src/macros.rs | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/vendor/partial_ref/src/macros.rs b/vendor/partial_ref/src/macros.rs new file mode 100644 index 000000000..49930e4d6 --- /dev/null +++ b/vendor/partial_ref/src/macros.rs @@ -0,0 +1,154 @@ +/// Declares a [`Part`]. +/// +/// Defines an empty struct type and derives all necessary instances to use it as a marker type for +/// parts. +/// +/// This macro can define [`AbstractPart`]s using `part!(PartName);` or `part!(pub PartName);` and +/// [`Field`] parts using `part!(PartName: FieldType);` or `part!(pub PartName: FieldType);`. +#[macro_export] +macro_rules! part { + ($part:ident) => { part!(@template $part () () ($crate::AbstractPart)); }; + (pub $part:ident) => { part!(@template $part () (pub) ($crate::AbstractPart)); }; + ($part:ident<> : $field:ty) => { part!($part : $field); }; + (pub $part:ident<> : $field:ty) => { part!(pub $part : $field); }; + ($part:ident<$($lt:lifetime),*> : $field:ty) => { + part!(@template $part ($($lt),*) () ($crate::Field<$field>) ($field)); + }; + (pub $part:ident<$($lt:lifetime),*> : $field:ty) => { + part!(@template $part ($($lt),*) (pub) ($crate::Field<$field>) ($field)); + }; + ($part:ident : $field:ty) => { part!(@template $part () () ($crate::Field<$field>)); }; + (pub $part:ident : $field:ty) => { part!(@template $part () (pub) ($crate::Field<$field>)); }; + (@template $part:ident () ($($vis:tt)*) ($($part_type:tt)*)) => { + #[derive(Default)] + $($vis)* struct $part; + impl $crate::Part for $part { + type PartType = $($part_type)*; + } + + impl $crate::PartSpec<$part> for $part {} + + // TODO maybe constrain InnerPart + impl<InnerPart: $crate::Part> ::std::ops::BitOr<InnerPart> for $part { + type Output = $crate::Nested<$part, InnerPart>; + + fn bitor(self, _rhs: InnerPart) -> Self::Output { + std::default::Default::default() + } + } + }; + (@template $part:ident ($($lt:lifetime),*) ($($vis:tt)*) ($($part_type:tt)*) ($field:ty)) => { + #[derive(Default)] + $($vis)* struct $part<$($lt),*> { + phantom: ::std::marker::PhantomData<$field>, + } + + #[allow(non_upper_case_globals)] + $($vis)* const $part: $part = $part { phantom: ::std::marker::PhantomData }; + + impl<$($lt),*> $crate::Part for $part<$($lt),*> { + type PartType = $($part_type)*; + } + + part!(@spec_template $part ($($lt),*)); + + // TODO maybe constrain InnerPart + impl<$($lt),*, InnerPart: $crate::Part> ::std::ops::BitOr<InnerPart> for $part<$($lt),*> { + type Output = $crate::Nested<$part<$($lt),*>, InnerPart>; + + fn bitor(self, _rhs: InnerPart) -> Self::Output { + std::default::Default::default() + } + } + }; + (@spec_template $part:ident ($l:lifetime)) => { + impl<'a, 'b> $crate::PartSpec<$part<'a>> for $part<'b> {} + }; + (@spec_template $part:ident ($l1:lifetime, $l2:lifetime)) => { + impl<'a1, 'a2, 'b1, 'b2> $crate::PartSpec<$part<'a1, 'a2>> for $part<'b1, 'b2> {} + }; + (@spec_template $part:ident ($l1:lifetime, $l2:lifetime, $l3:lifetime)) => { + impl<'a1, 'a2, 'a3, 'b1, 'b2, 'b3> + $crate::PartSpec<$part<'a1, 'a2, 'a3>> + for $part<'b1, 'b2, 'b3> {} + }; + (@spec_template $part:ident ($($tt:tt)*)) => { + // TODO avoid this limitation + compile_error!("parts with more than 3 lifetimes are not supported yet"); + }; +} + +/// Concise syntax for partial reference types. +/// +/// The first parameter is the reference target type, optionally preceded by a lifetime. The +/// following parameters are the referenced parts, each optionally preceded by the keyword `mut` to +/// indicate a mutable reference to that part. Nested parts can be specified using the pipe syntax +/// of [`nested_part`]. +/// +/// Examples: +/// * `partial!(Ty, PartA)` is `Const<PartA, Ref<Ty>>` +/// * `partial!('a Ty, mut PartA)` is `Mut<PartA, Ref<'a, Ty>>` +/// * `partial!(Ty, PartA, PartB, mut PartC)` is +/// `Const<PartA, Const<PartB, Mut<PartC, Ref<Ty>>` +/// * `partial!('a Ty, mut PartA | PartB)` is `Mut<Nested<PartA, PartB>, Ref<'a, Ty>>` +#[macro_export] +macro_rules! partial { + ($target_lt:lifetime $target:ty) => { $crate::Ref<$target_lt, $target> }; + ($target_lt:lifetime $target:ty, $($parts:tt)*) => { + partial!(@extend $crate::Ref<$target_lt, $target>, $($parts)*) + }; + ($target:ty) => { $crate::Ref<$target> }; + ($target:ty, $($parts:tt)* ) => { + partial!(@extend $crate::Ref<$target>, $($parts)*) + }; + (@extend $target:ty) => {$target}; + (@extend $target:ty, ) => {$target}; + (@extend $target:ty, mut $($part:ty)|* , $($rest:tt)*) => { + partial!(@extend $crate::Mut<$crate::nested_part!($($part)|*), $target>, $($rest)*) + }; + (@extend $target:ty, mut $($part:ty)|*) => { + partial!(@extend $target, mut $($part)|*, ) + }; + (@extend $target:ty, $($part:ty)|* , $($rest:tt)*) => { + partial!(@extend $crate::Const<$crate::nested_part!($($part)|*), $target>, $($rest)*) + }; + (@extend $target:ty, $($part:ty)|*) => { + partial!(@extend $target, $($part)|*, ) + }; +} + +/// Expands `A | B | ... | Z` to `Nested<...Nested<A, B>, ..., Z>` +/// +/// This mirrors the syntax for the expressions that can be passed to [`PartialRef`]'s part +/// functions. +#[macro_export] +macro_rules! nested_part { + ($target:ty) => { $target }; + ($target:ty | $part:ty) => { + $crate::Nested<$target , $part> + }; + ($target:ty | $part:ty | $($subparts:ty)|*) => { + nested_part!($crate::Nested<$target , $part> | $($subparts)|*) + }; +} + +/// Helper macro for splitting a partial reference. +/// +/// The statement `split_borrow!(target, rest = &(...) expr)` where `...` is a list of parts (same +/// syntax as used for [`partial`]) splits the partial reference returned by expr and binds the listed +/// parts to the identifier `target` and the remaining parts to the identifier `rest`. This is done +/// using [`PartialRef`]'s split_borrow method. +/// +/// As shorter version is available as `split_borrow!(target = &(...) ident)` which is identical to +/// `split_borrow!(target, ident = &(...) ident)`. This shadows the existing partial reference with +/// a new binding. +#[macro_export] +macro_rules! split_borrow { + ($target:ident = &($($parts:tt)*) $from:ident) => { + split_borrow!($target, $from = &($($parts)*) $from) + }; + ($target:ident, $rest:ident = &($($parts:tt)*) $from:expr) => { + #[allow(unused_variables, unused_mut)] + let (mut $target, mut $rest) = ($from).split_borrow::<partial!(_, $($parts)*), _>(); + }; +} |