Macro substrate::type_dispatch::dispatch_impl

dispatch_impl!() { /* proc-macro */ }

A function-like variant of impl_dispatch.

Syntax

The syntax is the same as impl_dispatch, but the contents of the attribute must now be contained by brackets ([]) or braces ({}).

Examples

struct GenericStruct<A, B>(A, B);

// Creates 4 trait implementations.
dispatch_impl!{
    [{u64; u16}, {u32, usize; u8, u64}]
    impl<A, B, C> Into<C> for GenericStruct<A, B> {
        fn into(self) -> C {
           self.0 as C + self.1 as C
       }
    }
}

let x: usize = GenericStruct(1u64, 3u32).into();
assert_eq!(x, 4);
let x: u64 = GenericStruct(1u64, 3u8).into();
assert_eq!(x, 4);
let x: usize = GenericStruct(1u16, 3u32).into();
assert_eq!(x, 4);
let x: u64 = GenericStruct(1u16, 3u8).into();
assert_eq!(x, 4);