Death to Type Classes

(jappie.me)

53 points | by zeepthee 3 days ago

8 comments

  • platz 13 minutes ago
    In the 2010-2020 era, readers of Hacker News used to know how to read Haskell and had strong opinions (pro and con) of it.

    That era is now over.

  • SkiFire13 6 hours ago
    I feel like this article would be much more approachable if it didn't assume readers already know Ocaml and Haskell and their module system
    • nine_k 5 hours ago
      Indeed so, but that would require a few months worth of work from the reader, unfortunately.

      (I have a t-shirt with a lambda in a circle, reminiscent of the anarchist emblem, and words "no class, no state". It's definitely possible to explain to a passer-by who never studied FP what it refers to, but not in such a way that the joke remained funny. Possibly the same deal is with the bumper sticker saying "my other car is cdr".)

      • codebje 5 hours ago
        "Humor can be dissected, as a frog can, but the thing dies in the process and the innards are discouraging to any but the pure scientific mind." - E. B. White.
      • DaiPlusPlus 3 hours ago
        > a lambda in a circle

        How often do people think you're a Half-Life fan instead?

        • dagurp 2 hours ago
          or Aphex Twin
    • fweimer 5 hours ago
      Haskell knowledge doesn't actually help because this isn't using the (very barebones) Haskell module system, but the Backpack extension: https://www.microsoft.com/en-us/research/wp-content/uploads/...
    • nesarkvechnep 3 hours ago
      Yeah, it’s better to not assume anything and be stuck in the basics forever, right?
    • 4ad 5 hours ago
      It would also be a useless article. It's fine to write for an audience, if you're not in the target audience, move on.
    • Vosporos 4 hours ago
      It's okay not to know things
    • actionfromafar 5 hours ago
      Yeah... meanwhile, in lesser languages, type classes is all we have.
  • indigoabstract 3 hours ago
    Delightfully weird and niche article.

    And I wouldn't be surprised if there were more retired left handed surgeons in their 50s living in rural Switzerland than people who understand what he's talking about.

  • mrkeen 1 hour ago

      In this case that’s the >>= from Maybe.Monad. As long as you satisfy the signature, it’s happy . do has nothing to do with Monads! Who lied to you?
    
    Could have been a stronger point by using a non-monadic >>=.

    I've been doing a lot of parsing lately and I find I don't need to reach all the way for monad (applicative is usually enough). But I guess that's what ApplicativeDo[1] is for.

      We’ve got to be explicit now which Functor or Monad we’re importing, and you can’t have do notation for different Monads in the same module.
    
    This is a bit rough for usability (not to mention also undermines the point above).

    But overall I like the approach of trying something radically new.

    [1] https://ghc.gitlab.haskell.org/ghc/doc/users_guide/exts/appl...

    • kccqzy 6 minutes ago
      ApplicativeDo can be thought of as a compile-time transformation that turns sequential code into possibly parallel* code just by analyzing the way variables are used. Once I've had that realization I really appreciated it more.

      *: By "possibly parallel" I mean the blocks of code are known to be independent from each other. They could be actually executed in parallel if the Applicative instance does so.

  • semiinfinitely 4 hours ago
    even for someone moderately interested in FP, this one goes above my head and the only take-away I can get from it is "maybe use ocaml instead of haskell"
    • seanparsons 5 minutes ago
      I'm reasonably versed in Haskell and my response would be that it shouldn't make that much difference to you what they've written in here. I've yet to see any code in the wild using the backpack extension.
  • test6554 5 hours ago
    I just picture Charlie from “It’s Always Sunny in Philadelphia” connecting the dots.
  • b_e_n_t_o_n 4 hours ago

       if err !== nil {
          return err
       }
  • 12_throw_away 4 hours ago
    "Functors" "Monads" "Typeclasses" <- concepts dreamed up by the utterly deranged