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They are interesting in purely functional languages like Haskell because they allow for side effects without sacficicing purity and referential transparency. Ra

by spion 2y ago

They are interesting in purely functional languages like Haskell because they allow for side effects without sacficicing purity and referential transparency. Rather than allowing side effects, you describe the program as, say, specs for the instruction to run, plus the function that decides what the next instruction is after the first instruction completes and yields a result. Kind of like a linked list of functions that return imperative instructions. I don't think the general concept is that interesting, at least in programming. Monoids, though simpler, are probably way more interesting (mapreduce, caching, etc)

chuckadams 2y ago
Monads are Monoids, so it's a good idea to build up an intuition for Monoids first. Then move up to Applicatives, and then finally Monads if you find you actually need them by then. By the time you get to them, Monads will be boring. Applicatives were dusty theory when I learned Monads, so they never burned themselves into my consciousness. I'm doing good with Monoids tho.
- lkitching 2y ago
  The way in which monads are monoids isn't really helpful for understanding them for progamming.
  - chuckadams 2y ago
    I dunno, it helped monads "click" for me at a theoretical level (they're just monoids in the category of endofunctors, what's the problem?) but by then I'd acquired a strong intuition of them already, so maybe it's not helpful for a novice. I'm pretty sure Applicatives help tho, LYAH seems to think so anyway. They sure would have helped me: the "Gentle Introduction to Haskell" was anything but.
    - spion 2y ago
      Monads being monoids isn't very interesting in a practical sense - e.g. just because you can associatively combine steps in a program isn't very interesting. (We do it all the time when we extract a subset of instructions as a procedure) I'd say monoids are more interesting, mainly due to implications for massively parallel algorithms and caching and how finding operations that fit the laws let you reap massive benefits in both aspects. I've yet to see something as practically interesting for monads. Perhaps monadic parsers or STM qualify. What would you say makes monads just as interesting in a practical sense?

by spion 2y ago

chuckadams 2y ago

Monads are Monoids, so it's a good idea to build up an intuition for Monoids first. Then move up to Applicatives, and then finally Monads if you find you actually need them by then. By the time you get to them, Monads will be boring. Applicatives were dusty theory when I learned Monads, so they never burned themselves into my consciousness. I'm doing good with Monoids tho.

lkitching 2y ago
The way in which monads are monoids isn't really helpful for understanding them for progamming.
- chuckadams 2y ago
  I dunno, it helped monads "click" for me at a theoretical level (they're just monoids in the category of endofunctors, what's the problem?) but by then I'd acquired a strong intuition of them already, so maybe it's not helpful for a novice. I'm pretty sure Applicatives help tho, LYAH seems to think so anyway. They sure would have helped me: the "Gentle Introduction to Haskell" was anything but.
  - spion 2y ago
    Monads being monoids isn't very interesting in a practical sense - e.g. just because you can associatively combine steps in a program isn't very interesting. (We do it all the time when we extract a subset of instructions as a procedure) I'd say monoids are more interesting, mainly due to implications for massively parallel algorithms and caching and how finding operations that fit the laws let you reap massive benefits in both aspects. I've yet to see something as practically interesting for monads. Perhaps monadic parsers or STM qualify. What would you say makes monads just as interesting in a practical sense?