struct Foo;
struct Bar;
#[deriving(Show)]
struct FooBar;
#[deriving(Show)]
struct BarFoo;
// The `Add<T, U>` trait needs two generic parameters:
// * T is the type of the RHS summand, and
// * U is the type of the sum
// This block implements the operation: Foo + Bar = FooBar
impl Add<Bar, FooBar> for Foo {
fn add(self, _rhs: Bar) -> FooBar {
println!("> Foo.add(&Bar) was called");
FooBar
}
}
// Addition can be implemented in a non-commutative way
// This block implements the operation: Bar + Foo = BarFoo
impl Add<Foo, BarFoo> for Bar {
fn add(self, _rhs: Foo) -> BarFoo {
println!("> Bar.add(&Foo) was called");
BarFoo
}
}
fn main() {
println!("Foo + Bar = {}", Foo + Bar);
println!("Bar + Foo = {}", Bar + Foo);
}