transitive

Transitive converions through derive macros for Rust.

Rationale:

Assume you have types A, B and C with the following, already implemented, conversions:

• A -> B
• B -> C

Sometimes it might be desirable to have an A -> C implementation which could easily be represented as A -> B -> C.

That is precisely what this crate does. Through the Transitive derive macro, it will implement From or TryFrom respectively for converting from/to the derived type and a target type, given a path of transitions to go through.

use transitive::Transitive;

#[derive(Transitive)]
#[transitive(into(B, C, D))] // impl From<A> for D by doing A -> B -> C -> D
struct A;

#[derive(Transitive)]
#[transitive(into(C, D))] // impl From<B> for D by doing B -> C -> D
struct B;
struct C;
struct D;

impl From<A> for B {
    fn from(val: A) -> Self {
        Self
    }
};

impl From<B> for C {
    fn from(val: B) -> Self {
        Self
    }
};

impl From<C> for D {
    fn from(val: C) -> Self {
        Self
    }
};

#[test]
fn into() {
    D::from(A);
    D::from(B);
}

More examples and explanations can be found in the documentation.

License

Licensed under MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT).

Contributing

Contributions to this repository, unless explicitly stated otherwise, will be considered licensed under MIT. Bugs/issues encountered can be opened here.