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
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236

/// For types `T`, `U` for which binary operator `binop` is implemented (`T binop U`), also implement `U binop T`.
/// This macro will fail if `LHS` = `RHS`.
///
/// For readability, the expected syntax of the macro is the following:
/// ```text
/// ( [ Generics ] )?
/// impl Trait, Method for LHS(, RHS)?
/// ( where Bounds )?
/// ```
/// - `Generics` are comma-seperated type or const generics
/// - `Trait` is the trait to be implemented
/// - `Method` is the method that `Trait` defines\
///   (can be ommitted for [`Add`](https://doc.rust-lang.org/std/ops/trait.Add.html) and [`Mul`](https://doc.rust-lang.org/std/ops/trait.Mul.html))
/// - `LHS` is the type of the left hand side of the original operation (i.e. `T`)
/// - `RHS` is the type of the right hand side of the original operation (i.e. `U`)
/// - `Bounds` are comma-seperated trait bounds for the listed generics
///
/// Note in particular that `LHS` and `RHS` denote the left and right side of the **original** operation, not the one being created. The reason for this is to be consistent with all other macros in this crate, even if it seems unintuitive.
#[macro_export]
macro_rules! commutative_binop {
    (
        $( [ $($generic:tt)* ] )?
        impl Add for $lhs:ty, $rhs:ty
        $( where $($bound:tt)* )?
    ) => {
        commutative_binop! {
            $( [ $($generic)* ] )?
            impl Add, add for $lhs, $rhs
            $( where $($bound)* )?
        }
    };
    (
        $( [ $($generic:tt)* ] )?
        impl Mul for $lhs:ty, $rhs:ty
        $( where $($bound:tt)* )?
    ) => {
        commutative_binop! {
            $( [ $($generic)* ] )?
            impl Mul, mul for $lhs, $rhs
            $( where $($bound)* )?
        }
    };

    (
        $( [ $($generic:tt)* ] )?
        impl $impl:ident, $meth:ident for $lhs:ty, $rhs:ty
        $( where $($bound:tt)* )?
    ) => {
        impl$(<$($generic)*>)? $impl<$lhs> for $rhs
        $(where
            $($bound)*)?
        {
            type Output = <$lhs as $impl<$rhs>>::Output;

            fn $meth(self, rhs: $lhs) -> Self::Output {
                <$lhs>::$meth(rhs, self)
            }
        }
    };
}

/// For types `T: Copy`, `U: Copy` for which binary operator `binop` is implemented (`T binop U`), also implement `T binop &U`, `&T binop U` and `&T binop &U`.
///
/// For readability, the expected syntax of the macro is the following:
/// ```text
/// ( [ Generics ] )?
/// impl Trait, Method for LHS(, RHS)?
/// ( where Bounds )?
/// ```
/// - `Generics` are comma-seperated type or const generics
/// - `Trait` is the trait to be implemented
/// - `Method` is the method that `Trait` defines\
///   (can be ommitted for [`Add`](https://doc.rust-lang.org/std/ops/trait.Add.html), [`Sub`](https://doc.rust-lang.org/std/ops/trait.Sub.html), [`Mul`](https://doc.rust-lang.org/std/ops/trait.Mul.html) and [`Div`](https://doc.rust-lang.org/std/ops/trait.Div.html))
/// - `LHS` is the type of the left hand side of the operation (i.e. `T`)
/// - `RHS` is the type of the right hand side of the operation (i.e. `U`)\
///   if no `RHS` is given, `LHS` = `RHS` is assumed
/// - `Bounds` are comma-seperated trait bounds for the listed generics
#[macro_export]
macro_rules! forward_ref_binop {
    (
        $( [ $($generic:tt)* ] )?
        impl Add for $lhs:ty $(, $rhs:ty )?
        $( where $($bound:tt)* )?
    ) => {
        forward_ref_binop! {
            $( [ $($generic)* ] )?
            impl Add, add for $lhs $(, $rhs )?
            $( where $($bound)* )?
        }
    };
    (
        $( [ $($generic:tt)* ] )?
        impl Sub for $lhs:ty $(, $rhs:ty )?
        $( where $($bound:tt)* )?
    ) => {
        forward_ref_binop! {
            $( [ $($generic)* ] )?
            impl Sub, sub for $lhs $(, $rhs )?
            $( where $($bound)* )?
        }
    };
    (
        $( [ $($generic:tt)* ] )?
        impl Mul for $lhs:ty $(, $rhs:ty )?
        $( where $($bound:tt)* )?
    ) => {
        forward_ref_binop! {
            $( [ $($generic)* ] )?
            impl Mul, mul for $lhs $(, $rhs )?
            $( where $($bound)* )?
        }
    };
    (
        $( [ $($generic:tt)* ] )?
        impl Div for $lhs:ty $(, $rhs:ty )?
        $( where $($bound:tt)* )?
    ) => {
        forward_ref_binop! {
            $( [ $($generic)* ] )?
            impl Div, div for $lhs $(, $rhs )?
            $( where $($bound)* )?
        }
    };

    // if no RHS was given, assume RHS = LHS
    (
        $( [ $($generic:tt)* ] )?
        impl $impl:ident, $meth:ident for $lhs:ty
        $( where $($bound:tt)* )?
    ) => {
        forward_ref_binop! {
            $( [ $($generic)* ] )?
            impl $impl, $meth for $lhs, $lhs
            $( where $($bound)* )?
        }
    };

    (
        $( [ $($generic:tt)* ] )?
        impl $impl:ident, $meth:ident for $lhs:ty, $rhs:ty
        $( where $($bound:tt)* )?
    ) => {
        impl$(<$($generic)*>)? $impl<$rhs> for &$lhs
        $(where
            $($bound)*)?
        {
            type Output = <$lhs as $impl<$rhs>>::Output;

            fn $meth(self, rhs: $rhs) -> Self::Output {
                <$lhs>::$meth(*self, rhs)
            }
        }

        impl$(<$($generic)*>)? $impl<&$rhs> for $lhs
        $(where
            $($bound)*)?
        {
            type Output = <$lhs as $impl<$rhs>>::Output;

            fn $meth(self, rhs: &$rhs) -> Self::Output {
                <$lhs>::$meth(self, *rhs)
            }
        }

        impl$(<$($generic)*>)? $impl<&$rhs> for &$lhs
        $(where
            $($bound)*)?
        {
            type Output = <$lhs as $impl<$rhs>>::Output;

            fn $meth(self, rhs: &$rhs) -> Self::Output {
                <$lhs>::$meth(*self, *rhs)
            }
        }
    };
}

/// For types `T: Copy`, `U: Copy` for which binary operator `binop` is implemented commutatively (`T binop U` **and** `U binop T`), also implement `T binop &U`, `&T binop U`, `&T binop &U`, `U binop &T`, `&U binop T` and `&U binop &T`.
/// This macro will fail if `LHS` = `RHS`.
///
/// For readability, the expected syntax of the macro is the following:
/// ```text
/// ( [ Generics ] )?
/// impl Trait, Method for LHS(, RHS)?
/// ( where Bounds )?
/// ```
/// - `Generics` are comma-seperated type or const generics
/// - `Trait` is the trait to be implemented
/// - `Method` is the method that `Trait` defines\
///   (can be ommitted for [`Add`](https://doc.rust-lang.org/std/ops/trait.Add.html) and [`Mul`](https://doc.rust-lang.org/std/ops/trait.Mul.html))
/// - `LHS` is the type of the left hand side of the original operation (i.e. `T`)
/// - `RHS` is the type of the right hand side of the original operation (i.e. `U`)
/// - `Bounds` are comma-seperated trait bounds for the listed generics
#[macro_export]
macro_rules! forward_ref_commutative_binop {
    (
        $( [ $($generic:tt)* ] )?
        impl Add for $lhs:ty, $rhs:ty
        $( where $($bound:tt)* )?
    ) => {
        forward_ref_commutative_binop! {
            $( [ $($generic)* ] )?
            impl Add, add for $lhs, $rhs
            $( where $($bound)* )?
        }
    };
    (
        $( [ $($generic:tt)* ] )?
        impl Mul for $lhs:ty, $rhs:ty
        $( where $($bound:tt)* )?
    ) => {
        forward_ref_commutative_binop! {
            $( [ $($generic)* ] )?
            impl Mul, mul for $lhs, $rhs
            $( where $($bound)* )?
        }
    };

    (
        $( [ $($generic:tt)* ] )?
        impl $impl:ident, $meth:ident for $lhs:ty, $rhs:ty
        $( where $($bound:tt)* )?
    ) => {
        forward_ref_generic::forward_ref_binop! {
            $( [ $($generic)* ] )?
            impl $impl, $meth for $lhs, $rhs
            $( where $($bound)* )?
        }

        forward_ref_generic::forward_ref_binop! {
            $( [ $($generic)* ] )?
            impl $impl, $meth for $rhs, $lhs
            $( where $($bound)* )?
        }
    };
}