core/
tuple.rs

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
// See core/src/primitive_docs.rs for documentation.

use crate::cmp::Ordering::{self, *};
use crate::marker::{ConstParamTy_, StructuralPartialEq, UnsizedConstParamTy};

// 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 {
    // 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 )+) => {
        maybe_tuple_doc! {
            $($T)+ @
            #[stable(feature = "rust1", since = "1.0.0")]
            impl<$($T: PartialEq),+> PartialEq for ($($T,)+)
            where
                last_type!($($T,)+): ?Sized
            {
                #[inline]
                fn eq(&self, other: &($($T,)+)) -> bool {
                    $( ${ignore($T)} self.${index()} == other.${index()} )&&+
                }
                #[inline]
                fn ne(&self, other: &($($T,)+)) -> bool {
                    $( ${ignore($T)} self.${index()} != other.${index()} )||+
                }
            }
        }

        maybe_tuple_doc! {
            $($T)+ @
            #[stable(feature = "rust1", since = "1.0.0")]
            impl<$($T: Eq),+> Eq for ($($T,)+)
            where
                last_type!($($T,)+): ?Sized
            {}
        }

        maybe_tuple_doc! {
            $($T)+ @
            #[unstable(feature = "adt_const_params", issue = "95174")]
            impl<$($T: ConstParamTy_),+> ConstParamTy_ for ($($T,)+)
            {}
        }

        maybe_tuple_doc! {
            $($T)+ @
            #[unstable(feature = "unsized_const_params", issue = "95174")]
            impl<$($T: UnsizedConstParamTy),+> UnsizedConstParamTy for ($($T,)+)
            {}
        }

        maybe_tuple_doc! {
            $($T)+ @
            #[unstable(feature = "structural_match", issue = "31434")]
            impl<$($T),+> StructuralPartialEq for ($($T,)+)
            {}
        }

        maybe_tuple_doc! {
            $($T)+ @
            #[stable(feature = "rust1", since = "1.0.0")]
            impl<$($T: PartialOrd),+> PartialOrd for ($($T,)+)
            where
                last_type!($($T,)+): ?Sized
            {
                #[inline]
                fn partial_cmp(&self, other: &($($T,)+)) -> Option<Ordering> {
                    lexical_partial_cmp!($( ${ignore($T)} self.${index()}, other.${index()} ),+)
                }
                #[inline]
                fn lt(&self, other: &($($T,)+)) -> bool {
                    lexical_ord!(lt, Less, $( ${ignore($T)} self.${index()}, other.${index()} ),+)
                }
                #[inline]
                fn le(&self, other: &($($T,)+)) -> bool {
                    lexical_ord!(le, Less, $( ${ignore($T)} self.${index()}, other.${index()} ),+)
                }
                #[inline]
                fn ge(&self, other: &($($T,)+)) -> bool {
                    lexical_ord!(ge, Greater, $( ${ignore($T)} self.${index()}, other.${index()} ),+)
                }
                #[inline]
                fn gt(&self, other: &($($T,)+)) -> bool {
                    lexical_ord!(gt, Greater, $( ${ignore($T)} self.${index()}, other.${index()} ),+)
                }
            }
        }

        maybe_tuple_doc! {
            $($T)+ @
            #[stable(feature = "rust1", since = "1.0.0")]
            impl<$($T: Ord),+> Ord for ($($T,)+)
            where
                last_type!($($T,)+): ?Sized
            {
                #[inline]
                fn cmp(&self, other: &($($T,)+)) -> Ordering {
                    lexical_cmp!($( ${ignore($T)} self.${index()}, other.${index()} ),+)
                }
            }
        }

        maybe_tuple_doc! {
            $($T)+ @
            #[stable(feature = "rust1", since = "1.0.0")]
            impl<$($T: Default),+> Default for ($($T,)+) {
                #[inline]
                fn default() -> ($($T,)+) {
                    ($({ let x: $T = Default::default(); x},)+)
                }
            }
        }

        maybe_tuple_doc! {
            $($T)+ @
            #[stable(feature = "array_tuple_conv", since = "1.71.0")]
            impl<T> From<[T; ${count($T)}]> for ($(${ignore($T)} T,)+) {
                #[inline]
                #[allow(non_snake_case)]
                fn from(array: [T; ${count($T)}]) -> Self {
                    let [$($T,)+] = array;
                    ($($T,)+)
                }
            }
        }

        maybe_tuple_doc! {
            $($T)+ @
            #[stable(feature = "array_tuple_conv", since = "1.71.0")]
            impl<T> From<($(${ignore($T)} T,)+)> for [T; ${count($T)}] {
                #[inline]
                #[allow(non_snake_case)]
                fn from(tuple: ($(${ignore($T)} T,)+)) -> Self {
                    let ($($T,)+) = tuple;
                    [$($T,)+]
                }
            }
        }
    }
}

// If this is a unary tuple, it adds a doc comment.
// Otherwise, it hides the docs entirely.
macro_rules! maybe_tuple_doc {
    ($a:ident @ #[$meta:meta] $item:item) => {
        #[doc(fake_variadic)]
        #[doc = "This trait is implemented for tuples up to twelve items long."]
        #[$meta]
        $item
    };
    ($a:ident $($rest_a:ident)+ @ #[$meta:meta] $item:item) => {
        #[doc(hidden)]
        #[$meta]
        $item
    };
}

// Constructs an expression that performs a lexical ordering using method `$rel`.
// The values are interleaved, so the macro invocation for
// `(a1, a2, a3) < (b1, b2, b3)` would be `lexical_ord!(lt, opt_is_lt, a1, b1,
// a2, b2, a3, b3)` (and similarly for `lexical_cmp`)
//
// `$ne_rel` is only used to determine the result after checking that they're
// not equal, so `lt` and `le` can both just use `Less`.
macro_rules! lexical_ord {
    ($rel: ident, $ne_rel: ident, $a:expr, $b:expr, $($rest_a:expr, $rest_b:expr),+) => {{
        let c = PartialOrd::partial_cmp(&$a, &$b);
        if c != Some(Equal) { c == Some($ne_rel) }
        else { lexical_ord!($rel, $ne_rel, $($rest_a, $rest_b),+) }
    }};
    ($rel: ident, $ne_rel: ident, $a:expr, $b:expr) => {
        // Use the specific method for the last element
        PartialOrd::$rel(&$a, &$b)
    };
}

macro_rules! lexical_partial_cmp {
    ($a:expr, $b:expr, $($rest_a:expr, $rest_b:expr),+) => {
        match ($a).partial_cmp(&$b) {
            Some(Equal) => lexical_partial_cmp!($($rest_a, $rest_b),+),
            ordering => ordering
        }
    };
    ($a:expr, $b:expr) => { ($a).partial_cmp(&$b) };
}

macro_rules! lexical_cmp {
    ($a:expr, $b:expr, $($rest_a:expr, $rest_b:expr),+) => {
        match ($a).cmp(&$b) {
            Equal => lexical_cmp!($($rest_a, $rest_b),+),
            ordering => ordering
        }
    };
    ($a:expr, $b:expr) => { ($a).cmp(&$b) };
}

macro_rules! last_type {
    ($a:ident,) => { $a };
    ($a:ident, $($rest_a:ident,)+) => { last_type!($($rest_a,)+) };
}

tuple_impls!(E D C B A Z Y X W V U T);