forward_ref 1.0.0

Rust's forward_ref_* macros for easier implementation of operator overloading.
Documentation 
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

//! Macros to simplify extending operator traits over references.
//!
//! Adapted from the Rust core library [internal_macros.rs] to remove standard
//! library internal attribute annotations and add usage documentation.
//!
//! [internal_macros.rs]: https://github.com/rust-lang/rust/blob/master/library/core/src/internal_macros.rs

/// Extend a unary operator trait impl over refs.
///
/// Given an implementation of `op T` where T is `Copy`able, implements the unary
/// operator `op &T`.
///
/// # Examples
/**
```rust
use core::ops::Neg;
use forward_ref::forward_ref_unop;

#[derive(Clone, Copy, Debug, PartialEq)]
struct MyInt(i32);

impl Neg for MyInt {
    type Output = Self;

    #[inline]
    fn neg(self) -> Self::Output {
        Self(self.0.neg())
    }
}

forward_ref_unop!(impl Neg, neg for MyInt);

// Now negation will work for references.
let a = MyInt(1);

assert_eq!(-a, MyInt(-1));
assert_eq!(-&a, MyInt(-1));
```
*/
#[macro_export]
macro_rules! forward_ref_unop {
    (impl $imp:ident, $method:ident for $t:ty) => {
        impl $imp for &$t {
            type Output = <$t as $imp>::Output;

            #[inline]
            fn $method(self) -> <$t as $imp>::Output {
                $imp::$method(*self)
            }
        }
    };
}

/// Extend a binary operator trait impl over refs.
///
/// Given an implementation of `T op U` where T and U are `Copy`able, implements
/// the binary operators:
/// - `&T op U`
/// - `T op &U`
/// - `&T op &U`
///
/// # Examples
/**
```rust
use core::ops::Add;
use forward_ref::forward_ref_binop;

#[derive(Clone, Copy, Debug, PartialEq)]
struct MyInt(i32);

impl Add for MyInt {
    type Output = Self;

    #[inline]
    fn add(self, rhs: Self) -> Self::Output {
        Self(self.0 + rhs.0)
    }
}

forward_ref_binop!(impl Add, add for MyInt, MyInt);

// Now addition will work for any combination of references and values.
let a = MyInt(1);
let b = MyInt(2);

assert_eq!(a + b, MyInt(3));
assert_eq!(&a + b, MyInt(3));
assert_eq!(a + &b, MyInt(3));
assert_eq!(&a + &b, MyInt(3));
```
*/
#[macro_export]
macro_rules! forward_ref_binop {
    (impl $imp:ident, $method:ident for $t:ty, $u:ty) => {
        impl<'a> $imp<$u> for &'a $t {
            type Output = <$t as $imp<$u>>::Output;

            #[inline]
            fn $method(self, other: $u) -> <$t as $imp<$u>>::Output {
                $imp::$method(*self, other)
            }
        }

        impl $imp<&$u> for $t {
            type Output = <$t as $imp<$u>>::Output;

            #[inline]
            fn $method(self, other: &$u) -> <$t as $imp<$u>>::Output {
                $imp::$method(self, *other)
            }
        }

        impl $imp<&$u> for &$t {
            type Output = <$t as $imp<$u>>::Output;

            #[inline]
            fn $method(self, other: &$u) -> <$t as $imp<$u>>::Output {
                $imp::$method(*self, *other)
            }
        }
    };
}

/// Extend an assignment operator trait impl over refs.
///
/// Given an implementation of `T op= U` where U is `Copy`able, implements
/// the binary operator `T op= &U`.
///
/// # Examples
/**
```rust
use core::ops::AddAssign;
use forward_ref::forward_ref_op_assign;

#[derive(Clone, Copy, Debug, PartialEq)]
struct MyInt(i32);

impl AddAssign for MyInt {
    #[inline]
    fn add_assign(&mut self, rhs: Self) {
        self.0 += rhs.0;
    }
}

forward_ref_op_assign!(impl AddAssign, add_assign for MyInt, MyInt);

// Now addition assignment will also work for references.
let mut a = MyInt(1);
let b = MyInt(2);

a += b;
assert_eq!(a, MyInt(3));

a += &b;
assert_eq!(a, MyInt(5));
```
*/
#[macro_export]
macro_rules! forward_ref_op_assign {
    (impl $imp:ident, $method:ident for $t:ty, $u:ty) => {
        impl $imp<&$u> for $t {
            #[inline]
            fn $method(&mut self, other: &$u) {
                $imp::$method(self, *other);
            }
        }
    };
}