Function tao_of_rust::ch03::traits::associated_type

pub fn associated_type()

trait: 关联类型

Base usage:

pub fn associated_type(){
    #[derive(Debug, PartialEq)]
    struct Foo(i32);
    #[derive(Debug, PartialEq)]
    struct Bar(i32, i32);
    trait Inst {
        type F;
        type B;
        fn new_foo(i: i32) -> Self::F;
        fn new_bar(i: i32) -> Self::B;
    }
    struct FooBar;
    impl Inst for FooBar {
        type F = Foo;
        type B = Bar;
        fn new_foo(i: i32) -> Foo {
            Foo(i)
        }
        fn new_bar(i: i32) -> Bar {
            Bar(i, i + 10)
        }
    }
    let f: Foo = FooBar::new_foo(10);
    assert_eq!(f, Foo(10));
    let b: Bar = FooBar::new_bar(20);
    assert_eq!(b, Bar(20, 30));
}
infer_generics();