Function tao_of_rust::ch03::generics::infer_generics

pub fn infer_generics()

泛型: 返回值自动推导

Base usage:

fn  infer_generics(){
    #[derive(Debug, PartialEq)]
    struct Foo(i32);
    #[derive(Debug, PartialEq)]
    struct Bar(i32, i32);
    trait Inst {
        fn new(i: i32) -> Self;
    }
    impl Inst for Foo {
        fn new(i: i32) -> Foo {
            Foo(i)
      }
    }
    impl Inst for Bar {
       fn new(i: i32) -> Bar {
           Bar(i, i + 10)
       }
    }
    fn foobar<T: Inst>(i: i32) -> T {
      T::new(i)
    }
    let f: Foo = foobar(10);
    assert_eq!(f, Foo(10));
    let b: Bar = foobar(20);
    assert_eq!(b, Bar(20, 30));
}
infer_generics();