core/
tuple.rs

1// See core/src/primitive_docs.rs for documentation.
2
3use crate::cell::CloneFromCell;
4use crate::cmp::Ordering::{self, *};
5use crate::marker::{ConstParamTy_, StructuralPartialEq};
6use crate::ops::ControlFlow::{self, Break, Continue};
7
8// Recursive macro for implementing n-ary tuple functions and operations
9//
10// Also provides implementations for tuples with lesser arity. For example, tuple_impls!(A B C)
11// will implement everything for (A, B, C), (A, B) and (A,).
12macro_rules! tuple_impls {
13    // Stopping criteria (1-ary tuple)
14    ($T:ident) => {
15        tuple_impls!(@impl $T);
16    };
17    // Running criteria (n-ary tuple, with n >= 2)
18    ($T:ident $( $U:ident )+) => {
19        tuple_impls!($( $U )+);
20        tuple_impls!(@impl $T $( $U )+);
21    };
22    // "Private" internal implementation
23    (@impl $( $T:ident )+) => {
24        maybe_tuple_doc! {
25            $($T)+ @
26            #[stable(feature = "rust1", since = "1.0.0")]
27            #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
28            impl<$($T: [const] PartialEq),+> const PartialEq for ($($T,)+) {
29                #[inline]
30                #[ferrocene::prevalidated]
31                fn eq(&self, other: &($($T,)+)) -> bool {
32                    $( ${ignore($T)} self.${index()} == other.${index()} )&&+
33                }
34                #[inline]
35                #[ferrocene::prevalidated]
36                fn ne(&self, other: &($($T,)+)) -> bool {
37                    $( ${ignore($T)} self.${index()} != other.${index()} )||+
38                }
39            }
40        }
41
42        maybe_tuple_doc! {
43            $($T)+ @
44            #[stable(feature = "rust1", since = "1.0.0")]
45            #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
46            impl<$($T: [const] Eq),+> const Eq for ($($T,)+)
47            {}
48        }
49
50        maybe_tuple_doc! {
51            $($T)+ @
52            #[unstable(feature = "adt_const_params", issue = "95174")]
53            #[unstable_feature_bound(unsized_const_params)]
54            impl<$($T: ConstParamTy_),+> ConstParamTy_ for ($($T,)+)
55            {}
56        }
57
58        maybe_tuple_doc! {
59            $($T)+ @
60            #[unstable(feature = "structural_match", issue = "31434")]
61            impl<$($T),+> StructuralPartialEq for ($($T,)+)
62            {}
63        }
64
65        maybe_tuple_doc! {
66            $($T)+ @
67            #[stable(feature = "rust1", since = "1.0.0")]
68            #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
69            impl<$($T: [const] PartialOrd),+> const PartialOrd for ($($T,)+)
70            {
71                #[inline]
72                fn partial_cmp(&self, other: &($($T,)+)) -> Option<Ordering> {
73                    lexical_partial_cmp!($( ${ignore($T)} self.${index()}, other.${index()} ),+)
74                }
75                #[inline]
76                fn lt(&self, other: &($($T,)+)) -> bool {
77                    lexical_ord!(lt, __chaining_lt, $( ${ignore($T)} self.${index()}, other.${index()} ),+)
78                }
79                #[inline]
80                fn le(&self, other: &($($T,)+)) -> bool {
81                    lexical_ord!(le, __chaining_le, $( ${ignore($T)} self.${index()}, other.${index()} ),+)
82                }
83                #[inline]
84                fn ge(&self, other: &($($T,)+)) -> bool {
85                    lexical_ord!(ge, __chaining_ge, $( ${ignore($T)} self.${index()}, other.${index()} ),+)
86                }
87                #[inline]
88                fn gt(&self, other: &($($T,)+)) -> bool {
89                    lexical_ord!(gt, __chaining_gt, $( ${ignore($T)} self.${index()}, other.${index()} ),+)
90                }
91                #[inline]
92                fn __chaining_lt(&self, other: &($($T,)+)) -> ControlFlow<bool> {
93                    lexical_chain!(__chaining_lt, $( ${ignore($T)} self.${index()}, other.${index()} ),+)
94                }
95                #[inline]
96                fn __chaining_le(&self, other: &($($T,)+)) -> ControlFlow<bool> {
97                    lexical_chain!(__chaining_le, $( ${ignore($T)} self.${index()}, other.${index()} ),+)
98                }
99                #[inline]
100                fn __chaining_gt(&self, other: &($($T,)+)) -> ControlFlow<bool> {
101                    lexical_chain!(__chaining_gt, $( ${ignore($T)} self.${index()}, other.${index()} ),+)
102                }
103                #[inline]
104                fn __chaining_ge(&self, other: &($($T,)+)) -> ControlFlow<bool> {
105                    lexical_chain!(__chaining_ge, $( ${ignore($T)} self.${index()}, other.${index()} ),+)
106                }
107            }
108        }
109
110        maybe_tuple_doc! {
111            $($T)+ @
112            #[stable(feature = "rust1", since = "1.0.0")]
113            #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
114            impl<$($T: [const] Ord),+> const Ord for ($($T,)+)
115            {
116                #[inline]
117                fn cmp(&self, other: &($($T,)+)) -> Ordering {
118                    lexical_cmp!($( ${ignore($T)} self.${index()}, other.${index()} ),+)
119                }
120            }
121        }
122
123        maybe_tuple_doc! {
124            $($T)+ @
125            #[stable(feature = "rust1", since = "1.0.0")]
126            impl<$($T: Default),+> Default for ($($T,)+) {
127                #[inline]
128                fn default() -> ($($T,)+) {
129                    ($({ let x: $T = Default::default(); x},)+)
130                }
131            }
132        }
133
134        maybe_tuple_doc! {
135            $($T)+ @
136            #[stable(feature = "array_tuple_conv", since = "1.71.0")]
137            // can't do const From due to https://github.com/rust-lang/rust/issues/144280
138            impl<T> From<[T; ${count($T)}]> for ($(${ignore($T)} T,)+) {
139                #[inline]
140                #[allow(non_snake_case)]
141                fn from(array: [T; ${count($T)}]) -> Self {
142                    let [$($T,)+] = array;
143                    ($($T,)+)
144                }
145            }
146        }
147
148        maybe_tuple_doc! {
149            $($T)+ @
150            #[stable(feature = "array_tuple_conv", since = "1.71.0")]
151            // can't do const From due to https://github.com/rust-lang/rust/issues/144280
152            impl<T> From<($(${ignore($T)} T,)+)> for [T; ${count($T)}] {
153                #[inline]
154                #[allow(non_snake_case)]
155                fn from(tuple: ($(${ignore($T)} T,)+)) -> Self {
156                    let ($($T,)+) = tuple;
157                    [$($T,)+]
158                }
159            }
160        }
161
162        maybe_tuple_doc! {
163            $($T)+ @
164            // SAFETY: tuples introduce no additional indirection, so they can be copied whenever T
165            // can.
166            #[unstable(feature = "cell_get_cloned", issue = "145329")]
167            unsafe impl<$($T: CloneFromCell),+> CloneFromCell for ($($T,)+)
168            {}
169        }
170    }
171}
172
173// If this is a unary tuple, it adds a doc comment.
174// Otherwise, it hides the docs entirely.
175macro_rules! maybe_tuple_doc {
176    ($a:ident @ #[$meta:meta] $item:item) => {
177        #[doc(fake_variadic)]
178        #[doc = "This trait is implemented for tuples up to twelve items long."]
179        #[$meta]
180        $item
181    };
182    ($a:ident $($rest_a:ident)+ @ #[$meta:meta] $item:item) => {
183        #[doc(hidden)]
184        #[$meta]
185        $item
186    };
187}
188
189// Constructs an expression that performs a lexical ordering using method `$rel`.
190// The values are interleaved, so the macro invocation for
191// `(a1, a2, a3) < (b1, b2, b3)` would be `lexical_ord!(lt, opt_is_lt, a1, b1,
192// a2, b2, a3, b3)` (and similarly for `lexical_cmp`)
193//
194// `$chain_rel` is the chaining method from `PartialOrd` to use for all but the
195// final value, to produce better results for simple primitives.
196macro_rules! lexical_ord {
197    ($rel: ident, $chain_rel: ident, $a:expr, $b:expr, $($rest_a:expr, $rest_b:expr),+) => {{
198        match PartialOrd::$chain_rel(&$a, &$b) {
199            Break(val) => val,
200            Continue(()) => lexical_ord!($rel, $chain_rel, $($rest_a, $rest_b),+),
201        }
202    }};
203    ($rel: ident, $chain_rel: ident, $a:expr, $b:expr) => {
204        // Use the specific method for the last element
205        PartialOrd::$rel(&$a, &$b)
206    };
207}
208
209// Same parameter interleaving as `lexical_ord` above
210macro_rules! lexical_chain {
211    ($chain_rel: ident, $a:expr, $b:expr $(,$rest_a:expr, $rest_b:expr)*) => {{
212        PartialOrd::$chain_rel(&$a, &$b)?;
213        lexical_chain!($chain_rel $(,$rest_a, $rest_b)*)
214    }};
215    ($chain_rel: ident) => {
216        Continue(())
217    };
218}
219
220macro_rules! lexical_partial_cmp {
221    ($a:expr, $b:expr, $($rest_a:expr, $rest_b:expr),+) => {
222        match ($a).partial_cmp(&$b) {
223            Some(Equal) => lexical_partial_cmp!($($rest_a, $rest_b),+),
224            ordering => ordering
225        }
226    };
227    ($a:expr, $b:expr) => { ($a).partial_cmp(&$b) };
228}
229
230macro_rules! lexical_cmp {
231    ($a:expr, $b:expr, $($rest_a:expr, $rest_b:expr),+) => {
232        match ($a).cmp(&$b) {
233            Equal => lexical_cmp!($($rest_a, $rest_b),+),
234            ordering => ordering
235        }
236    };
237    ($a:expr, $b:expr) => { ($a).cmp(&$b) };
238}
239
240tuple_impls!(E D C B A Z Y X W V U T);
core/tuple.rs

core/
tuple.rs
