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I tried Haskell for 5 years

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Re: I tried Haskell for 5 years

#181

Post by dllthomas »

zzalpha wrote: post #106
arnon wrote: post #74

We have a code base of roughly 200,000 lines of Haskell code, dealing with high performance SQL query parsing, compilation and optimizations. I only remember one situation over the past 5 years that we had a performance issue with Haskell, that was solved by using the profiling capabilities of GHC. I disagree that performance is hard to figure out. It could be better, yes - but it's not that different than what you'd…

but it's not that different than what you'd get with other programming languages. Until you have to solve a (maddeningly common) space leak issue. That's a problem unique to lazily evaluated languages (basically Haskell) and is godawful to debug. It reminds me of solving git problems... you suddenly find yourself having to tear back the abstraction layer that is the language and compiler and start thinking about thun…

> unique to lazily evaluated languages

More precisely, unique to significant use of laziness, which is going to (obviously) be more common in lazily evaluated languages but laziness is supported elsewhere.

Re: I tried Haskell for 5 years

#182

Post by filterfish »

tonyedgecombe wrote: post #38
agumonkey wrote: post #34

Earlier quoted context omitted.

I just saw a haskell meetup where they're using haskell for devops. Basically static typing the underlying machine configurations. As usual, being an Haskell code, the abstraction is generalized and you can apply the logic on other domains.

https://propellor.branchable.com/ I would guess.

I've been using propellor for a few months now and it'fantastic. It takes a little while to get your round it but compared to puppet, chef and ansible, of which I've used all, it's a breath of fresh air.

Re: I tried Haskell for 5 years

#183

Post by dllthomas »

zzalpha wrote: post #153
platz wrote: post #142

Earlier quoted context omitted.

here is a method that can help debug space leaks: http://neilmitchell.blogspot.com/2015/09/detecting-space-lea...

I wish the problem was simply detecting and isolating space leaks. My experience is that actually fixing them can be incredibly difficult, hence my comment about needing to understand the gory details about how the runtime evaluates lazy expressions. Heck, that post even uses the phrase "Attempt to fix the space leak" as it's often not an obvious slam dunk. Sometimes it even devolves to peppering !'s around until the…

> My experience is that actually fixing them can be incredibly difficult

My experience differs, FWIW. If you know where you're creating too many thunks, and you force them as you create them, they don't accumulate.

Making sure you actually are forcing them, and not simply suspending a "force this", is probably the trickiest bit until you're used to the evaluation model.

Re: I tried Haskell for 5 years

#184

Post by dllthomas »

knz42 wrote: post #105
arnon wrote: post #74

We have a code base of roughly 200,000 lines of Haskell code, dealing with high performance SQL query parsing, compilation and optimizations. I only remember one situation over the past 5 years that we had a performance issue with Haskell, that was solved by using the profiling capabilities of GHC. I disagree that performance is hard to figure out. It could be better, yes - but it's not that different than what you'd…

Hi can you tell us a bit more about this SQL-related project? I'm rather practically interested.

If you want more generic SQL tooling in Haskell, my project was just recently open sourced (https://github.com/uber/queryparser). It currently has support for Vertica, Hive, and Presto; adding support for more dialects isn't complicated. I'm working on cleaning it up for hackage.

Re: I tried Haskell for 5 years

#185

Post by [deleted] »

gjkood wrote: post #16

Question to the Haskell experts here. Is Haskell more academic in nature or used heavily in Production environments? Is there an application sweet spot/domain (say Artificial Intelligence/Machine Learning, etc) where it shines over using other languages (I am not talking about software/language architectural issues like type systems or such)? I have no experience with Haskell but do use functional languages such as E…

[deleted]

Re: I tried Haskell for 5 years

#186

Post by tathougies »

hzhou321 wrote: post #120
tathougies wrote: post #92

Earlier quoted context omitted.

> and where trivial problems are the subject of ongoing academic research Like what?

I am not holding that (joke's) view, but monad came to mind as an ongoing academic research (to original Haskell at least) in order to solve a rather trivial stateful programming (trivial in an imperative style). To generalize that example, there are solutions that are trivial to express in an imperative style but seems convoluted in pure functional programming. How to retain the trivialness are subject of ongoing ac…

This confuses me. You don't really need monads to perform io or specify sequencing in Haskell, although do notation is very convenient for sequencing sctions.

Ultimately, if you want imperative style, you can just write imperative code that's well typed in Haskell.

Re: I tried Haskell for 5 years

#187

Post by Safety1stClyde »

> If you read an article from 10 years ago about the best way to do something in the language, that article is probably outdated by two generations.

Thank you, that is all I need to know about Haskell. I won't be learning Haskell then, in the same way that I won't have anything to do with C++. I don't have enough time to use these fashion-dominated and fad-obsessed programming languages.

Re: I tried Haskell for 5 years

#188

Post by blackRust »

gjkood wrote: post #16

Question to the Haskell experts here. Is Haskell more academic in nature or used heavily in Production environments? Is there an application sweet spot/domain (say Artificial Intelligence/Machine Learning, etc) where it shines over using other languages (I am not talking about software/language architectural issues like type systems or such)? I have no experience with Haskell but do use functional languages such as E…

Haskell in production (mostly) at: https://scrive.com/

Re: I tried Haskell for 5 years

#190

Post by nv-vn »

elihu wrote: post #174
throwaway110034 wrote: post #116

Earlier quoted context omitted.

> you can just start writing in a declarative style and not worry about debugging, because everything is checked by the type system That is dangerously close to the infamous "if it compiles, then it works" boast, which Haskellers make all the time (while denying that they make it), demonstrating in the process that they don't write real software, where the defects one encounters are very often of a nature such that t…

There's no conspiracy; programming in Haskell is the most fun I've ever had with a computer. The "if it compiles, it works" thing describes people's experience. It isn't always true and it isn't a valid excuse not to do proper testing, but in Haskell a non-working solution is usually at least broken in a way that makes sense in the context of the problem you're trying to solve. If you program an incorrect solution to…

I'm not sure how this corresponds to your experience with Haskell, but as an OCaml user there's been numerous times where I have been forced to write large chunks of code without a compiler/IDE to aid me at all (e.g. VM wasn't working so had to work from Windows temporarily). In each of these cases, upon compilation, I have been greeted by a flood of errors (syntax errors, type errors, and everything in between). However, without exception, the program has always worked as expected when I ran it the first time. I think it's reasonably plausible that one could write a program the magnitude of ~5k lines in Haskell and have it work on the first attempt.
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