Almost five years ago, Saoirse “boats” wrote “Notes on a smaller Rust”, and a year after that, revisited the idea.
The basic idea is a language that is highly inspired by Rust but doesn’t have the strict constraint of being a “systems” language in the vein of C and C++; in particular, it can have a nontrivial (or “thick”) runtime and doesn’t need to limit itself to “zero-cost” abstractions.
What languages are being designed that fit this description? I’ve seen a few scripting languages written in Rust on GitHub, but none of them have been very active. I also recently learned about Hylo, which does have some ideas that I think are promising, but it seems too syntactically alien to really be a “smaller Rust.”
Edit to add: I think Graydon Hoare’s post about language design choices he would have preferred for Rust also sheds some light on the kind of things a hypothetical “Rust-like but not Rust” language could do differently: https://graydon2.dreamwidth.org/307291.html
Well the project never left its roots, it’s a still a simple system-f implementation, and a lot of ideas. I’ve put it on ice, after seeing how much involved there is with questionable outcome (and I need to dedicate a good amount of time to get the theory right, it’s not that I have year long research experience background in type-theory etc.). There’s more concrete problems than designing yet another language… Maybe I’ll come back to that project at some time.
Anyway the idea was to have something like Nix but more general (including derivations, possibly controlled side-effects). Closest to that currently would be typescripts object type, Haskell (overall static typing), crystal-langs union type and nickel (which is less ambitious (probably for good reason)).