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I’m curious if there are any that were especially uncomfortable to implement in Haskell. I’m a very very novice “functional programmer” but on occasion I find

I’m curious if there are any that were especially uncomfortable to implement in Haskell. I’m a very very novice “functional programmer” but on occasion I find problems that feel just ridiculous to implement FP style.

sfn42 2y ago
I'm not much of a functional programmer either, but generally in the beginning you'll feel this way because you're not used to thinking about problems in a functional way. You're used to solving problems with imperative structures. So you try to implement that in a functional language and it turns out completely stupid because the language isn't made to solve problems that way. But it usually has good ways to solve things.
- galangalalgol 2y ago
  I got stuck trying to have an intuition about what would explode my memory usage due to lazy eval, I never got a grip on the transition from pseudofunctional at the io boundaries into real functional internally either.
- anonzzzies 2y ago
  I like fp and array programming and logic programming (and the overlap) to solve problems that are (considered or for real; I don't usually know going in) really a bad fit for those and then implement them shorter and faster than in their imperative implementation. For some things it does not work obviously, but it's a really nice exercise for when in the gym, walking, cooking, driving and such; the performant or LoC optimising parts fit in my head so I can do the rewrites there and find ways to make them fit. For instance; going from an imperative piece of code to array programming (k/j), you have to find a way to translate the problem to a vector/matrix manipulation problem and that you can do while doing something else entirely. When you find a good one fit, it can be many, many times faster than the original just like that.
anardil 2y ago
Definitely. Depending on how long you've spent staring at the contents of /bin/ and /usr/bin/ you'll notice there are definitely some array or matrix oriented utils (or options) missing like column. cut comes to mind as a difficult one. In C, you can just hop around the char buffer[] and drop nulls in place for fields, etc before printing. You could go that way a Data.Array Char, but that's hard to justify as functional.
- Muromec 2y ago
  Shouldn't cut but the easiest one to do in functional style? You basicaly map one line of a stream to another with some filtering and joining. Do I miss the part where it's terribly slow and/or not doable in Haskell or something?

sfn42 2y ago

I'm not much of a functional programmer either, but generally in the beginning you'll feel this way because you're not used to thinking about problems in a functional way. You're used to solving problems with imperative structures. So you try to implement that in a functional language and it turns out completely stupid because the language isn't made to solve problems that way. But it usually has good ways to solve things.

galangalalgol 2y ago
I got stuck trying to have an intuition about what would explode my memory usage due to lazy eval, I never got a grip on the transition from pseudofunctional at the io boundaries into real functional internally either.
anonzzzies 2y ago
I like fp and array programming and logic programming (and the overlap) to solve problems that are (considered or for real; I don't usually know going in) really a bad fit for those and then implement them shorter and faster than in their imperative implementation. For some things it does not work obviously, but it's a really nice exercise for when in the gym, walking, cooking, driving and such; the performant or LoC optimising parts fit in my head so I can do the rewrites there and find ways to make them fit. For instance; going from an imperative piece of code to array programming (k/j), you have to find a way to translate the problem to a vector/matrix manipulation problem and that you can do while doing something else entirely. When you find a good one fit, it can be many, many times faster than the original just like that.

anardil 2y ago

Definitely. Depending on how long you've spent staring at the contents of /bin/ and /usr/bin/ you'll notice there are definitely some array or matrix oriented utils (or options) missing like column. cut comes to mind as a difficult one. In C, you can just hop around the char buffer[] and drop nulls in place for fields, etc before printing. You could go that way a Data.Array Char, but that's hard to justify as functional.

Muromec 2y ago
Shouldn't cut but the easiest one to do in functional style? You basicaly map one line of a stream to another with some filtering and joining. Do I miss the part where it's terribly slow and/or not doable in Haskell or something?