wu VS tao

If you want some prior work on this, I've implemented effect-objects-as-return-values in my own language Tao, using uniqueness types. There's still work to be done, but I think it's sufficient as a proof of concept that this approach is viable without type soup.

I've personally found through my experiments working on my language Tao that having effects be a property of the return value and not the function itself is very useful and opens up a lot of doors, like iterators that generate effectful values and more precise control over when side effects occur and in what context.

If you’d like to see some examples of great error messages written by a language with a parser combinator, I recommend you check out tao, which is parsed via chumsky, and provides rust-like error messages with the help of ariadne! I have been fiddling with writing my own language for a while now, and after trying out the alternatives, I found Chumsky to be great to work with, and can not recommend it enough. There are also great examples that you can find in the repo as well!

Tao: A statically-typed functional language\ (0 comments)

I've been developing both throughout the development of Tao, my own hobby language. It's since developed quite an extensive syntax (see here for an example: https://github.com/zesterer/tao/blob/master/examples/99.tao), so you can count it as evidence that chumsky scales to complex grammars: https://github.com/zesterer/tao