This is (for now) just ExpHP's personal project reimplementing some of the ideas in frunk, attempting to explore the design space a bit more.
This probably won't ever be published. Instead, I hope to use what I learn here to contribute ideas to another similar project (probably frunk?).
(note: examples are most likely broken by the time you read this)
let list_a = hlist![A1, A2, A3];
let list_b = hlist![B1, B2, B3];
// Find the indices for sculpting
let sculptor = list_a.sculptor_of::<HList![A3, A1], _>();
// Apply them to both lists.
let (hlist_pat![A3, A1], hlist_pat![A2]) = list_a.sculpt_at(sculptor);
let (hlist_pat![B3, B1], hlist_pat![B2]) = list_b.sculpt_at(sculptor);
// Notice that the type of `list_b.sculpt_at(sculptor)` is always
// immediately known, without any help from type inference;
// the following does not produce a "Type annotations needed" error.
assert_eq!(list_b.sculpt_at(sculptor), list_b.sculpt_at(sculptor));sculpt can turn Coprod![A, B, C, D, E] into Either<Coprod![C, A, E]>, Coprod![B, D]>.
embed can turn Coprod![C, A, E] into Coprod![A, B, C, D, E].
(actually wait a second, isn't embed just a special case of sculpt where the remainder is void?)
(ehhhhhhh I'll do something about that later)
Yes, the indices on the type-directed lookup methods really do have to be type parameters.
No, they can't be turned into associated types. Try it, I dare you.
Don't.
If you just wanna try it out for kicks, you should use a git dependency with a rev tag: (this repo has no tags yet)
[dependencies]
funky = { rev = "777777777777", git = "https://github.com/ExpHP/funky" }Licensed under either of
- Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Wait, what?! You want to contribute... to this?!
Well... alrighty, then. Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.