this post was submitted on 22 Jun 2023
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Functional Programming

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Hello fellow FP-Lemmyites. I'd love to hear stories about what got you interested in FP originally, and how you learned.

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[โ€“] grayrest 3 points 1 year ago (1 children)

Rust is not a FP language. It's an imperative language with restricted state and a few FP constructs included.

To me what makes a language FP is the mindset and that boils down to deciding to fold instead of loop and you lean to closure captures instead of declaring variables. Both sides of these are basically equivalent but having a function as the big hammer you use to nail everything together is what makes it functional programming instead of X programming with some functional ideas carried over.

When people structure a request like this they're generally after a way to really get into the ideas and the best way to do that is to use a language that's built around FP ideas. I personally recommend Clojure and OCaml. If you'd like to do Scheme via the Wizard book then that's fine as well. I don't really like the pure functional languages (Haskell and friends) because I think that state is a useful thing in small doses and don't like jumping through the extra hoops to get at it.

[โ€“] philm 1 points 1 year ago

Rust is not a purely FP language, indeed, but I think it's absolutely fine to program almost only FP in it, then you have almost no issues with the borrow-checker. Though since it's a multiparadigm, I obviously decide for each problem the best approach which is not always FP... Often it's just simpler to read imperative code. But I almost always default to fold in Rust anyways.

Though e.g. currying and the likes is certainly more fun in real FP languages (like Haskell).

The more experience I get in all these languages the more I think Rust has found the "perfect" balance of paradigms and readability (well at least to date). But this is obviously also a matter of personal preference... I'm really looking forward that all the boilerplate is reduced when programming with a lot of generic trait-bounds (i.e. more inference where it makes sense), I think this is still an area where Rust could improve (also compile times, like incremental trait solving).