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
|
// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
/*!
The `Ord` and `Eq` comparison traits
This module contains the definition of both `Ord` and `Eq` which define
the common interfaces for doing comparison. Both are language items
that the compiler uses to implement the comparison operators. Rust code
may implement `Ord` to overload the `<`, `<=`, `>`, and `>=` operators,
and `Eq` to overload the `==` and `!=` operators.
*/
/**
* Trait for values that can be compared for equality and inequality.
*
* This trait allows partial equality, where types can be unordered instead of strictly equal or
* unequal. For example, with the built-in floating-point types `a == b` and `a != b` will both
* evaluate to false if either `a` or `b` is NaN (cf. IEEE 754-2008 section 5.11).
*
* Eventually, this will be implemented by default for types that implement `TotalEq`.
*/
#[lang="eq"]
pub trait Eq {
fn eq(&self, other: &Self) -> bool;
fn ne(&self, other: &Self) -> bool;
}
/// Trait for equality comparisons where `a == b` and `a != b` are strict inverses.
pub trait TotalEq {
fn equals(&self, other: &Self) -> bool;
}
macro_rules! totaleq_impl(
($t:ty) => {
impl TotalEq for $t {
#[inline(always)]
fn equals(&self, other: &$t) -> bool { *self == *other }
}
}
)
totaleq_impl!(bool)
totaleq_impl!(u8)
totaleq_impl!(u16)
totaleq_impl!(u32)
totaleq_impl!(u64)
totaleq_impl!(i8)
totaleq_impl!(i16)
totaleq_impl!(i32)
totaleq_impl!(i64)
totaleq_impl!(int)
totaleq_impl!(uint)
#[deriving(Eq)]
pub enum Ordering { Less, Equal, Greater }
/// Trait for types that form a total order
pub trait TotalOrd: TotalEq {
fn cmp(&self, other: &Self) -> Ordering;
}
macro_rules! totalord_impl(
($t:ty) => {
impl TotalOrd for $t {
#[inline(always)]
fn cmp(&self, other: &$t) -> Ordering {
if *self < *other { Less }
else if *self > *other { Greater }
else { Equal }
}
}
}
)
totalord_impl!(u8)
totalord_impl!(u16)
totalord_impl!(u32)
totalord_impl!(u64)
totalord_impl!(i8)
totalord_impl!(i16)
totalord_impl!(i32)
totalord_impl!(i64)
totalord_impl!(int)
totalord_impl!(uint)
/**
* Trait for values that can be compared for a sort-order.
*
* Eventually this may be simplified to only require
* an `le` method, with the others generated from
* default implementations. However it should remain
* possible to implement the others separately, for
* compatibility with floating-point NaN semantics
* (cf. IEEE 754-2008 section 5.11).
*/
#[lang="ord"]
pub trait Ord {
fn lt(&self, other: &Self) -> bool;
fn le(&self, other: &Self) -> bool;
fn ge(&self, other: &Self) -> bool;
fn gt(&self, other: &Self) -> bool;
}
#[inline(always)]
pub fn lt<T:Ord>(v1: &T, v2: &T) -> bool {
(*v1).lt(v2)
}
#[inline(always)]
pub fn le<T:Ord>(v1: &T, v2: &T) -> bool {
(*v1).le(v2)
}
#[inline(always)]
pub fn eq<T:Eq>(v1: &T, v2: &T) -> bool {
(*v1).eq(v2)
}
#[inline(always)]
pub fn ne<T:Eq>(v1: &T, v2: &T) -> bool {
(*v1).ne(v2)
}
#[inline(always)]
pub fn ge<T:Ord>(v1: &T, v2: &T) -> bool {
(*v1).ge(v2)
}
#[inline(always)]
pub fn gt<T:Ord>(v1: &T, v2: &T) -> bool {
(*v1).gt(v2)
}
/// The equivalence relation. Two values may be equivalent even if they are
/// of different types. The most common use case for this relation is
/// container types; e.g. it is often desirable to be able to use `&str`
/// values to look up entries in a container with `~str` keys.
pub trait Equiv<T> {
fn equiv(&self, other: &T) -> bool;
}
#[inline(always)]
pub fn min<T:Ord>(v1: T, v2: T) -> T {
if v1 < v2 { v1 } else { v2 }
}
#[inline(always)]
pub fn max<T:Ord>(v1: T, v2: T) -> T {
if v1 > v2 { v1 } else { v2 }
}
#[cfg(test)]
mod test {
#[test]
fn test_int_totalord() {
assert_eq!(5.cmp(&10), Less);
assert_eq!(10.cmp(&5), Greater);
assert_eq!(5.cmp(&5), Equal);
assert_eq!((-5).cmp(&12), Less);
assert_eq!(12.cmp(-5), Greater);
}
#[test]
fn test_int_totaleq() {
assert!(5.equals(&5));
assert!(!2.equals(&17));
}
}
|
