The great thing about Rust is that it’s open source. This means you can see how the authors of the language have solved a problem. The closest analogue is primitive integer types:
macro_rules! add_impl {
($($t:ty)*) => ($(
#[stable(feature = "rust1", since = "1.0.0")]
impl Add for $t {
type Output = $t;
#[inline]
fn add(self, other: $t) -> $t { self + other }
}
forward_ref_binop! { impl Add, add for $t, $t }
)*)
}
forward_ref_binop
is defined as:
macro_rules! forward_ref_binop {
(impl $imp:ident, $method:ident for $t:ty, $u:ty) => {
#[stable(feature = "rust1", since = "1.0.0")]
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)
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<'a> $imp<&'a $u> for $t {
type Output = <$t as $imp<$u>>::Output;
#[inline]
fn $method(self, other: &'a $u) -> <$t as $imp<$u>>::Output {
$imp::$method(self, *other)
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<'a, 'b> $imp<&'a $u> for &'b $t {
type Output = <$t as $imp<$u>>::Output;
#[inline]
fn $method(self, other: &'a $u) -> <$t as $imp<$u>>::Output {
$imp::$method(*self, *other)
}
}
}
}
It’s certainly valid to write wrapper implementations of the traits for references that simply dereference and call the value-oriented version.