bjoernager/rust
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Implement tuples using recursion

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Caio 2022-04-12 16:23:36 -03:00
parent 1f7fb6413d
commit 23bf977758
1 changed files with 77 additions and 70 deletions
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49
library/core/src/tuple.rs
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@ -3,12 +3,27 @@
use crate::cmp::Ordering::*; use crate::cmp::Ordering::*;
use crate::cmp::*; use crate::cmp::*;
// macro for implementing n-ary tuple functions and operations // Recursive macro for implementing n-ary tuple functions and operations
//
// Also provides implementations for tuples with lesser arity. For example, tuple_impls!(A B C)
// will implement everything for (A, B, C), (A, B) and (A,).
macro_rules! tuple_impls { macro_rules! tuple_impls {
( $( ( $( $T:ident )+ ) )+ ) => { // Stopping criteria (1-ary tuple)
$( ($T:ident) => {
tuple_impls!(@impl $T);
};
// Running criteria (n-ary tuple, with n >= 2)
($T:ident $( $U:ident )+) => {
tuple_impls!($( $U )+);
tuple_impls!(@impl $T $( $U )+);
};
// "Private" internal implementation
(@impl $( $T:ident )+) => {
#[stable(feature = "rust1", since = "1.0.0")] #[stable(feature = "rust1", since = "1.0.0")]
impl<$($T:PartialEq),+> PartialEq for ($($T,)+) where last_type!($($T,)+): ?Sized { impl<$($T:PartialEq),+> PartialEq for ($($T,)+)
where
last_type!($($T,)+): ?Sized
{
#[inline] #[inline]
fn eq(&self, other: &($($T,)+)) -> bool { fn eq(&self, other: &($($T,)+)) -> bool {
$( ${ignore(T)} self.${index()} == other.${index()} )&&+ $( ${ignore(T)} self.${index()} == other.${index()} )&&+
@ -20,7 +35,10 @@ macro_rules! tuple_impls {
} }
#[stable(feature = "rust1", since = "1.0.0")] #[stable(feature = "rust1", since = "1.0.0")]
impl<$($T:Eq),+> Eq for ($($T,)+) where last_type!($($T,)+): ?Sized {} impl<$($T:Eq),+> Eq for ($($T,)+)
where
last_type!($($T,)+): ?Sized
{}
#[stable(feature = "rust1", since = "1.0.0")] #[stable(feature = "rust1", since = "1.0.0")]
impl<$($T:PartialOrd + PartialEq),+> PartialOrd for ($($T,)+) impl<$($T:PartialOrd + PartialEq),+> PartialOrd for ($($T,)+)
@ -50,7 +68,10 @@ macro_rules! tuple_impls {
} }
#[stable(feature = "rust1", since = "1.0.0")] #[stable(feature = "rust1", since = "1.0.0")]
impl<$($T:Ord),+> Ord for ($($T,)+) where last_type!($($T,)+): ?Sized { impl<$($T:Ord),+> Ord for ($($T,)+)
where
last_type!($($T,)+): ?Sized
{
#[inline] #[inline]
fn cmp(&self, other: &($($T,)+)) -> Ordering { fn cmp(&self, other: &($($T,)+)) -> Ordering {
lexical_cmp!($( ${ignore(T)} self.${index()}, other.${index()} ),+) lexical_cmp!($( ${ignore(T)} self.${index()}, other.${index()} ),+)
@ -64,7 +85,6 @@ macro_rules! tuple_impls {
($({ let x: $T = Default::default(); x},)+) ($({ let x: $T = Default::default(); x},)+)
} }
} }
)+
} }
} }
@ -105,17 +125,4 @@ macro_rules! last_type {
($a:ident, $($rest_a:ident,)+) => { last_type!($($rest_a,)+) }; ($a:ident, $($rest_a:ident,)+) => { last_type!($($rest_a,)+) };
} }
tuple_impls! { tuple_impls!(A B C D E F G H I J K L);
(A)
(A B)
(A B C)
(A B C D)
(A B C D E)
(A B C D E F)
(A B C D E F G)
(A B C D E F G H)
(A B C D E F G H I)
(A B C D E F G H I J)
(A B C D E F G H I J K)
(A B C D E F G H I J K L)
}