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Comment by Jenk | Hacker News Reader

The tooling (Visual Studio, LSPs, etc.) around F# is very lacklustre, I wish it had better support from MS. At the moment F# just seems to be a playground for experimenting with FP ideas that then get ported to C#.

As for learning a functional language, I recommend this Haskell tutorial[0], and accompanying video series of an experienced haskeller (Brian McKenna) running through it[1]. I've read countless texts and tutorials explaining Haskell and FP to me but it didn't fully click until I saw someone with experience using the language and tooling effectively.

[0]: https://github.com/system-f/fp-course [1]: https://www.youtube.com/playlist?list=PLly9WMAVMrayYo2c-1E_r...

There are a few other video series from other experienced haskellers available that may be better, too, I just haven't watched them so I cannot comment.

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I appreciate the response. As someone that struggles with higher-level math, am I going to get a benefit out of starting with Haskell? I have built financial systems in various languages, so my issue isn't necessarily how to code math functionality. It's more of the abstract concepts that get me.

I believe you will, yes. You may not be able to jump right in to some of the deep discussions about type categories, I certainly can't, but I still have learned a lot from Haskell and both continue to use Haskell itself and use what it has taught me in other languages to my betterment.

Thank you for the explanation and suggestion. Sounds like it will be worth my effort to at least learn, just for new ways of developing, and how that affects any other language I touch.

As a quick example, a lot of what @Iceland_jack has mentioned I can make sense of, but I wouldn't have been able to contribute to that. I guess it is a bit like learning a foreign language and I am at the point of being able to understand what a native speaker is saying to me, but my responses are probably garbled nonsense. :) However I am still confident that what I have learnt has empowered me to be a better developer.

The abstract concepts give you the tools to quickly classify a datatype. They are not limited to Haskell and let you ask the right questions of datatypes in any language.

The foundational concept is functoriality, i.e. mapping over the argument of a type. Whether a datatype has an instance of

1. (covariant) Functor

2. Contravariant functor

3. Functor+Contravariant (phantom argument), or

4. neither

says a lot about its structure and tells me what further questions I can ask (what hierarchies I can expect): A datatype can only be a Monad if is covariant. It can only be Divisible and Decidable if it is contravariant. If it is both (3.) then its argument is not used (phantom) and can be mapped to any type. If it is neither (4.) it can be invariant (where the argument appears in both positive and negative position: like the Endo datatype) or a more complicated datatype like GADT, which would require a more complicated functor.

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