rust-ape-example/src/bin/generics.rs

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// ./src/generics.md
// A concrete type `A`.
struct A;
// In defining the type `Single`, the first use of `A` is not preceded by `<A>`.
// Therefore, `Single` is a concrete type, and `A` is defined as above.
struct Single(A);
// ^ Here is `Single`s first use of the type `A`.
// Here, `<T>` precedes the first use of `T`, so `SingleGen` is a generic type.
// Because the type parameter `T` is generic, it could be anything, including
// the concrete type `A` defined at the top.
struct SingleGen<T>(T);
fn part0() {
// `Single` is concrete and explicitly takes `A`.
let _s = Single(A);
// Create a variable `_char` of type `SingleGen<char>`
// and give it the value `SingleGen('a')`.
// Here, `SingleGen` has a type parameter explicitly specified.
let _char: SingleGen<char> = SingleGen('a');
// `SingleGen` can also have a type parameter implicitly specified:
let _t = SingleGen(A); // Uses `A` defined at the top.
let _i32 = SingleGen(6); // Uses `i32`.
let _char = SingleGen('a'); // Uses `char`.
}
pub fn main() {
part0();
}