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I [author] must say I'm slightly embarrassed to see this turn up here now. This is not a terribly deep or interesting post. Read http://marijnhaverbeke.nl/blog/

by marijn 13y ago

I [author] must say I'm slightly embarrassed to see this turn up here now. This is not a terribly deep or interesting post. Read http://marijnhaverbeke.nl/blog/tern.html http://marijnhaverbeke.nl/blog/tern.html or http://marijnhaverbeke.nl/blog/acorn.html http://marijnhaverbeke.nl/blog/acorn.html or http://marijnhaverbeke.nl/blog/browser-input-reading.html http://marijnhaverbeke.nl/blog/browser-input-reading.html instead.

momo-reina 13y ago
I enjoyed reading the code =)
moomin 13y ago
Don't be. The fundamental observation that monad's usability is tied closely to Haskell's features is important, and still hasn't been taken on board elsewhere. There's always someone trying to do monads in Clojure...
- octo_t 13y ago
  Scala has plenty of monads and they work fine.
  - rtpg 13y ago
    Scala also has some pretty powerful syntax to go with
  - marijn 13y ago
    Scala has a much more powerful type system than Clojure
    - moomin 13y ago
      100% true, but not as powerful as Haskell's. Not sure you can usefully have inheritance and return type overloading.
      - samth 13y ago
        The Scala and Haskell type systems are incomparable, and the typeclass aspects that are most relevant to monad usability are doable with implicits.
  - fusiongyro 13y ago
    Yes, but doesn't it also have the three requirements mentioned by the article: ML-style function foo, something akin to type classes, and polymorphic return types?
    - yohanatan 13y ago
      In Scala, currying is not all-pervasive. You have to be explicit about it (and it's a definite pain point).
- bunderbunder 13y ago
  Yup. If I had read this article when it was first written instead of now, I probably would have produced a fair bit less unnecessarily complicated and difficult-to-maintain code over the past several years. Instead, I had to figure out why I was having such a hard time coming up with a satisfactory implementation of the pattern in C# - and why I maybe shouldn't have wanted one in the first place - the hard way.
  - alipang 13y ago
    Just curious, why would you argue that you shouldn't have wanted it the first place? Monads are one thing, which you can approximate somewhat via LINQ, but there are other simpler patterns such as Monoid, that really makes sense to use as programming construct, that just somehow never works in C#.
    - bunderbunder 13y ago
      Because it seems like there always turns out to be some other approach that works better and is more idiomatic in C#. Usually something really forehead-smackingly obvious like mutation or a callback.
mightybyte 13y ago
Don't be embarrassed about this. I think it's a very important point. I've heard monads getting buzz outside the Haskell community and it almost always misses the point. I gave a presentation at the NYC Haskell meetup that made essentially the same point as you, but came at it from a different angle. You wrote this post quite awhile earlier, but it's nice to know that we independently came to the same conclusions.

by marijn 13y ago

momo-reina 13y ago

I enjoyed reading the code =)

moomin 13y ago

Don't be. The fundamental observation that monad's usability is tied closely to Haskell's features is important, and still hasn't been taken on board elsewhere. There's always someone trying to do monads in Clojure...

octo_t 13y ago
Scala has plenty of monads and they work fine.
- rtpg 13y ago
  Scala also has some pretty powerful syntax to go with
- marijn 13y ago
  Scala has a much more powerful type system than Clojure
  - moomin 13y ago
    100% true, but not as powerful as Haskell's. Not sure you can usefully have inheritance and return type overloading.
    - samth 13y ago
      The Scala and Haskell type systems are incomparable, and the typeclass aspects that are most relevant to monad usability are doable with implicits.
- fusiongyro 13y ago
  Yes, but doesn't it also have the three requirements mentioned by the article: ML-style function foo, something akin to type classes, and polymorphic return types?
  - yohanatan 13y ago
    In Scala, currying is not all-pervasive. You have to be explicit about it (and it's a definite pain point).
bunderbunder 13y ago
Yup. If I had read this article when it was first written instead of now, I probably would have produced a fair bit less unnecessarily complicated and difficult-to-maintain code over the past several years. Instead, I had to figure out why I was having such a hard time coming up with a satisfactory implementation of the pattern in C# - and why I maybe shouldn't have wanted one in the first place - the hard way.
- alipang 13y ago
  Just curious, why would you argue that you shouldn't have wanted it the first place? Monads are one thing, which you can approximate somewhat via LINQ, but there are other simpler patterns such as Monoid, that really makes sense to use as programming construct, that just somehow never works in C#.
  - bunderbunder 13y ago
    Because it seems like there always turns out to be some other approach that works better and is more idiomatic in C#. Usually something really forehead-smackingly obvious like mutation or a callback.

mightybyte 13y ago

Don't be embarrassed about this. I think it's a very important point. I've heard monads getting buzz outside the Haskell community and it almost always misses the point. I gave a presentation at the NYC Haskell meetup that made essentially the same point as you, but came at it from a different angle. You wrote this post quite awhile earlier, but it's nice to know that we independently came to the same conclusions.