learnhaskell VS haskell-handbook

learnhaskell

https://github.com/bitemyapp/learnhaskell/blob/master/dialog...

> a transducer is recognizing that the signature of foldl splits

> type Transducer a b = forall r. (r -> b -> r) -> (r -> a -> r)

> they compose like lenses

The author maintains an opinionated path to learning Haskell[0], albeit lacking the criticism of resources that ultimately do not make it into his final recommendation.

[0] https://github.com/bitemyapp/learnhaskell

I find the following type signature captures the essence:

type Transducer x y = forall b. (b -> y -> b) -> (b -> x -> b)

https://github.com/bitemyapp/learnhaskell/blob/master/dialog...

There's some resources here: https://github.com/bitemyapp/learnhaskell

Other than that, I'm afraid your issues are too broad to help much. If you're having trouble getting anywhere, I would recommend starting with some basic tutorial. Here are some decent ones. Haskell is not a language you can just pick up unless you have prior functional programming experience.

This is the best meta-guide I know of to learning Haskell: https://github.com/bitemyapp/learnhaskell

All together that was a thoughtful and fair write up, thanks for that! I think you are spot on regarding monad transformers. Testing story is very good, the only part that I found harder then I would like it to be is testing IO code - there are some solutions that help but still, it is a bit surprisingly complex. And Template Haskell - it is not as hard as it sounds! Can be quite powerful without super deep knowledge. Btw here is short "cheat sheet" for Template Haskell that I wrote as notes for myself and others in the company: https://github.com/wasp-lang/haskell-handbook/blob/master/template-haskell.md .

haskell-handbook

I am trying to do something similar with https://github.com/wasp-lang/haskell-handbook, but much less ambitious - it is mostly there for me and my colleagues, not as a general guide, and is for intermediate level, not beginners, also has no order, just topics. But what I do is create issues with quick drafts and then fill them in when I have time and others can also add to it.

Wrote some popular tutorials on Haskell concepts, like https://wasp-lang.dev/blog/2021/09/01/haskell-forall-tutorial, and also are maintaining haskell handbook (still in infancy): https://github.com/wasp-lang/haskell-handbook .

I actually wrote a short text about how functions behave as Functor, Applicative or Monad: https://github.com/wasp-lang/haskell-handbook/blob/master/function-as-functor-applicative-monad.md .

Recently I realized I have no idea how should I define version bounds for my library and I got pretty confused before I finally figured out the reasoning behind it (thanks to r/haskell and Adam Bergmark from Stackage), so I thought I would capture that reasoning in a short article: https://github.com/wasp-lang/haskell-handbook/blob/master/dependencies-version-bounds.md .

As a result I decided to write a small article that gives overview of Cabal and Stack are and also compares them, based on what I learned: https://github.com/wasp-lang/haskell-handbook/blob/master/cabal-and-stack.md .