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I tried Haskell for 5 years

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Re: I tried Haskell for 5 years

#201

Post by Buttons840 »

hota_mazi wrote: post #169
marcosdumay wrote: post #67

Earlier quoted context omitted.

Haskell has a preference for looking academic, and is one of the favorites on academic circles. But that does not mean it's not used within industry. I'd say that people mostly do not know what is running in industry. It could be any share of anything. We get a hint looking at job offers; Haskell is small there, but not unheard of. On the sweet spot, Haskell is great for modeling complex domains; it's great for long-…

> and is one of the favorites on academic circles. I'd argue Python is much more prevalent with researchers than Haskell.

I think they mean programming language research.

Re: I tried Haskell for 5 years

#202

Post by dpratt71 »

throwaway110034 wrote: post #95

I will never, ever use Haskell in production because of its default evaluation strategy, the wrongness of which was tacitly conceded not long ago with the addition of the strictness pragma (which only works per-module) to GHC. I think it's especially telling that its community skews so heavily towards this blogger/monad tutorial writer dilettante demographic rather than the D. Richard Hipp/Walter Bright 'actually get…

There is a fellow by the name of Jon Harrop who has in times pasted "showed up" when Haskell came up for discussion. To say that he does not like Haskell is putting it mildly. I have the impression that the mere existence of Haskell is a personal affront to him.

What struck me about your post was how much it sounded like something he would write, in particular the interpretation of facts (a strictness pragma was recently introduced to Haskell) in the most extremely negative way possible (said pragma is admission that Haskell's default evaluation strategy is simply "wrong").

If you are not he, you should look him up, as I expect you two (?) would get along fantastically.

Re: I tried Haskell for 5 years

#203

Post by jinfiesto »

ashark wrote: post #139
nimih wrote: post #107

Earlier quoted context omitted.

Maybe something like: class Foldable myFoldable where foldl :: (summary -> element -> summary) -> summary -> myFoldable element -> summary This is the translation I do in my head when I read that type signature, at least.

Wow. That's much better. Apparently-idiomatic Haskell reads (or, rather, doesn't) about like line-noise/code-golf style Perl to me.

The problem with this is that there are Foldables that do not behave in the way that is implied by the above re-write of the parameters.

I think this is kind of the problem when you are really high up in abstraction-land. The functions that you're using are so generic that it's hard to say that they operate on anything in particular, except that the arguments fulfill certain properties or laws.

Re: I tried Haskell for 5 years

#204

Post by devrandomguy »

> Types / Type-driven development Rating: Best in class

> Haskell definitely does not have the most advanced type system (not even close if you count research languages) but out of all languages that are actually used in production Haskell is probably at the top.

What are these other research languages, that have such incredible type systems? Do they usually have implemented compilers, or would they only be described in an abstract form? Can I explore them for fun and curiosity?

Re: I tried Haskell for 5 years

#205

Post by tines »

devrandomguy wrote: post #204

> Types / Type-driven development Rating: Best in class > Haskell definitely does not have the most advanced type system (not even close if you count research languages) but out of all languages that are actually used in production Haskell is probably at the top. What are these other research languages, that have such incredible type systems? Do they usually have implemented compilers, or would they only be described…

The fact that he mentions type driven development probably means that he has dependent typing around, probably as seen in the language Idris, whose recently published book is called the same. Idris is very much not just an abstract language.

Re: I tried Haskell for 5 years

#206

Post by devrandomguy »

tines wrote: post #205
devrandomguy wrote: post #204

> Types / Type-driven development Rating: Best in class > Haskell definitely does not have the most advanced type system (not even close if you count research languages) but out of all languages that are actually used in production Haskell is probably at the top. What are these other research languages, that have such incredible type systems? Do they usually have implemented compilers, or would they only be described…

The fact that he mentions type driven development probably means that he has dependent typing around, probably as seen in the language Idris, whose recently published book is called the same. Idris is very much not just an abstract language.

Yes, the author mentioned Idris shortly afterwards, but I get the impression that this is just the tip of an iceberg. Idris was presented as the one example that is most likely to evolve from a research-only language, to a production language.

Re: I tried Haskell for 5 years

#207

Post by zzzzzzzza »

hzhou321 wrote: post #170
zzzzzzzza wrote: post #158

Earlier quoted context omitted.

Well I can't argue with the contention that there's a level of subjectivity here. However your definition of expressiveness is most likely positively correlated with the one I provided; furthermore, while you may be able to more quickly "express an idea" in a dynamically typed language, your ability to precisely enumerate the idea will be less than a statically typed one. I've been writing haskell for only several mo…

> furthermore, while you may be able to more quickly "express an idea" in a dynamically typed language, your ability to precisely enumerate the idea will be less than a statically typed one. What we need realize is not all ideas are precise. In fact, most of our ideas are vague to certain extent. They are still OK as long as the vagueness does not matter to the problem of interest or it is already constrained or impl…

I agree to some extent, but haskell pureness for example , which I take to refer to monads and other concepts from category theory in haskell, is actually very very abstract; the "constraint" of pureness (IO monad) just leads to the design of more consistent and very general interfaces; once you become familiar with these interfaces you are quicker than you would otherwise be, also haskell's type inference help alot with expressiveness vs. dynamic languages. In fact, personally my road to really learning haskell was through converting shell scripts to haskell, a task typically left to dynamic languages but which haskell might actually be uniquely suited for contrary to convential wisdom due to aforementioned factors.

Not saying haskell is some kind of panacea, doesn't run in as many environments as javascript, and can't handle programs that require very high performance at very low latencies due to garbage collection.

For web dev, the library situation seems very mature to me.

Re: I tried Haskell for 5 years

#208

Post by whateveracct »

proaralyst wrote: post #137
throwaway110034 wrote: post #95

I will never, ever use Haskell in production because of its default evaluation strategy, the wrongness of which was tacitly conceded not long ago with the addition of the strictness pragma (which only works per-module) to GHC. I think it's especially telling that its community skews so heavily towards this blogger/monad tutorial writer dilettante demographic rather than the D. Richard Hipp/Walter Bright 'actually get…

My impression on the consensus was that laziness was good for the tree (computation) but bad for the leaves (datatypes); hence the good practice of using strictness annotations on datatypes.

> hence the good practice of using strictness annotations on datatypes.

It's such a good practice that there's -XStrictData (different than the pragma mentioned by GP)

Re: I tried Haskell for 5 years

#209

Post by dllthomas »

marcosdumay wrote: post #198
haskellandchill wrote: post #171

Earlier quoted context omitted.

I can name two Haskell consultancies off the top of my head :)

But what if those two are busy right now? What if geography is a problem? Compare with how many Java consultancies do you think you can find on a quick search? I don't think the Haskell development labor market is nearly liquid enough to rely on consultants. For full time jobs the picture is very different.

> But what if those two are busy right now?

Then he'll have to look up some that he can't name off the top of his head? I can't name any Java consultancies, but I'm nonetheless confident that there are plenty...

With regard to Haskell, there are a lot of people interested in Haskell work compared to the number of positions presently available.

Re: I tried Haskell for 5 years

#210

Post by zzalpha »

theoh wrote: post #199
zzalpha wrote: post #191

Earlier quoted context omitted.

If you know where you're creating too many thunks, and you force them as you create them, they don't accumulate. Translation: if you've internalized the way Haskell code is compiled and executes, so that you can easily reason about how lazy evaluation is actually implemented, you can solve these problems. If not, it devolves to throwing !'s in and praying. Which is basically my point. If I don't have a hope of solvin…

This sounds a bit FUD-ish. Programming in any language involves understanding the evaluation strategy. You seem to be advocating languages that can be used with a level of ignorance or innocence which in practice just isn't possible. https://en.wikipedia.org/wiki/Evaluation_strategy

I disagree. I contend that most of the time folks ignore the evaluation strategy for eagerly evaluated languages because they're simply easier to reason about. That strikes me as objectively true on its face and I believe most Haskellers would concede that point.

The only time I can think of where that's not the case is when microoptimizing for performance, where the exact instructions being produced and their impact on pipelining and cache behaviour matter. But that's in general far more rare than one encounters space leaks in idiomatic Haskell.

Heck, one just needs to read about two of the most common Haskell functions to hit concerns about space leaks: foldl and foldr. It's just part of the way of life for a Haskeller.

There's simply no analog that I can think of in the world of eagerly evaluated languages that a) requires as much in-depth knowledge of the language implementation, and b) is so commonly encountered.

The closest thing I can come up with in a common, eager language might be space leaks in GC'd languages, but they're pretty rare unless you're doing something odd (e.g. keeping references to objects from a static variable).

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