num-traits/bigint/src/macros.rs

macro_rules! forward_val_val_binop {
    (impl $imp:ident for $res:ty, $method:ident) => {
        impl $imp<$res> for $res {
            type Output = $res;

            #[inline]
            fn $method(self, other: $res) -> $res {
                // forward to val-ref
                $imp::$method(self, &other)
            }
        }
    }
}

macro_rules! forward_val_val_binop_commutative {
    (impl $imp:ident for $res:ty, $method:ident) => {
        impl $imp<$res> for $res {
            type Output = $res;

            #[inline]
            fn $method(self, other: $res) -> $res {
                // forward to val-ref, with the larger capacity as val
                if self.data.capacity() >= other.data.capacity() {
                    $imp::$method(self, &other)
                } else {
                    $imp::$method(other, &self)
                }
            }
        }
    }
}

macro_rules! forward_ref_val_binop {
    (impl $imp:ident for $res:ty, $method:ident) => {
        impl<'a> $imp<$res> for &'a $res {
            type Output = $res;

            #[inline]
            fn $method(self, other: $res) -> $res {
                // forward to ref-ref
                $imp::$method(self, &other)
            }
        }
    }
}

macro_rules! forward_ref_val_binop_commutative {
    (impl $imp:ident for $res:ty, $method:ident) => {
        impl<'a> $imp<$res> for &'a $res {
            type Output = $res;

            #[inline]
            fn $method(self, other: $res) -> $res {
                // reverse, forward to val-ref
                $imp::$method(other, self)
            }
        }
    }
}

macro_rules! forward_val_ref_binop {
    (impl $imp:ident for $res:ty, $method:ident) => {
        impl<'a> $imp<&'a $res> for $res {
            type Output = $res;

            #[inline]
            fn $method(self, other: &$res) -> $res {
                // forward to ref-ref
                $imp::$method(&self, other)
            }
        }
    }
}

macro_rules! forward_ref_ref_binop {
    (impl $imp:ident for $res:ty, $method:ident) => {
        impl<'a, 'b> $imp<&'b $res> for &'a $res {
            type Output = $res;

            #[inline]
            fn $method(self, other: &$res) -> $res {
                // forward to val-ref
                $imp::$method(self.clone(), other)
            }
        }
    }
}

macro_rules! forward_ref_ref_binop_commutative {
    (impl $imp:ident for $res:ty, $method:ident) => {
        impl<'a, 'b> $imp<&'b $res> for &'a $res {
            type Output = $res;

            #[inline]
            fn $method(self, other: &$res) -> $res {
                // forward to val-ref, choosing the larger to clone
                if self.data.len() >= other.data.len() {
                    $imp::$method(self.clone(), other)
                } else {
                    $imp::$method(other.clone(), self)
                }
            }
        }
    }
}

// Forward everything to ref-ref, when reusing storage is not helpful
macro_rules! forward_all_binop_to_ref_ref {
    (impl $imp:ident for $res:ty, $method:ident) => {
        forward_val_val_binop!(impl $imp for $res, $method);
        forward_val_ref_binop!(impl $imp for $res, $method);
        forward_ref_val_binop!(impl $imp for $res, $method);
    };
}

// Forward everything to val-ref, so LHS storage can be reused
macro_rules! forward_all_binop_to_val_ref {
    (impl $imp:ident for $res:ty, $method:ident) => {
        forward_val_val_binop!(impl $imp for $res, $method);
        forward_ref_val_binop!(impl $imp for $res, $method);
        forward_ref_ref_binop!(impl $imp for $res, $method);
    };
}

// Forward everything to val-ref, commutatively, so either LHS or RHS storage can be reused
macro_rules! forward_all_binop_to_val_ref_commutative {
    (impl $imp:ident for $res:ty, $method:ident) => {
        forward_val_val_binop_commutative!(impl $imp for $res, $method);
        forward_ref_val_binop_commutative!(impl $imp for $res, $method);
        forward_ref_ref_binop_commutative!(impl $imp for $res, $method);
    };
}