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I tried Haskell for 5 years

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Re: I tried Haskell for 5 years

#171

Post by haskellandchill »

marcosdumay wrote: post #162
ChemicalWarfare wrote: post #97

Earlier quoted context omitted.

>> I'd say that people mostly do not know what is running in industry well if anyone does know what's out there then HN crowd would be a pretty good suspect in that regard. I personally have done my fair share of consulting and prof services engagements - dozens of them across all kinds of industries - I've never seen a Haskell shop. Java, Python, JS, Golang, Scala, Clojure, .Net, C, PHP - definitely out there in the…

Your experience may be biased. If I had a shop that depended on external consultants for development, I'd avoid any language that I'm not certain to be mainstream. It's just too risky.

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

Re: I tried Haskell for 5 years

#172

Post by salimmadjd »

choxi wrote: post #8

If anyone's curious to try out functional programming, I would highly recommend Elm. I haven't been so excited about a language since I went from C to Ruby ten years ago, and Pragmatic Studios has a great course on it (I have no affiliation): https://pragmaticstudio.com/courses/elm

Elm is also my gateway drug into functional. And Pragmatic Studio was a great start.

Monads then seemed much easier to understand after Elm and reading this: http://adit.io/posts/2013-04-17-functors,_applicatives,_and_...

Re: I tried Haskell for 5 years

#173

Post by beojan »

posterboy wrote: post #79
moomin wrote: post #24

Earlier quoted context omitted.

Application sweet spot is a funny thing, because it's mostly determined by the presence of specific libraries. What Haskell has more than anything is ridiculously general libraries. It's got perfectly good libraries for web development, Postgres access &access, but the only place I'd say it's got a real application-specific strength in libraries is parsing. Weirdly, what Haskell is good at is generality. Which is muc…

"academic/hobbyist" probably doesn't give justice to the benefit those works provide for languages that implement experiments pioneered in i.e. haskell. I say "probably" because I can't give any exact examples.

This is really a specific example of the benefit academia generally provides to society being highly underappreciated.

Re: I tried Haskell for 5 years

#174

Post by elihu »

throwaway110034 wrote: post #116
nv-vn wrote: post #96

Earlier quoted context omitted.

The point of the article was focusing on things to fix. Having used Haskell, there's a great many things that were worth the cost of learning it. For one thing, it's made me a vastly better programmer in other languages. It lets me appreciate better styles of writing code and think outside the box when solving things. Using Haskell also gives me the tools for many projects to write code almost thoughtlessly -- you ca…

> 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 a problem, you'll probably get a wrong answer. But a wrong answer is different than nonsense, which is what you get if, say, you write past the end of an array in C.

The Haskell type system is a very good nonsense filter, and probably a majority of programming errors are from telling the program to do something nonsensical. If you filter those out, sometimes what's left is a working program.

A Haskell programmer is unlikely to write a several thousand line program and have it work correctly the first time, but even large programs are written in small pieces. When those small pieces work correctly the first time, it's gratifying.

Re: I tried Haskell for 5 years

#175

Post by whateveracct »

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…

> 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.

Why must you publicly post something so wrong?

Re: I tried Haskell for 5 years

#176

Post by adamwk »

ahakki wrote: post #168
adamwk wrote: post #151

Earlier quoted context omitted.

The Sieve of Eratosthenes is a good example of relatively trivial in imperative code but a research paper in Haskell.

I am pretty sure the sieve can be written like this in Haskell, which might be a bit short for a research paper: sieve :: Integral a => a -> [a] sieve l = sieve' [2..l] [] where sieve' (p:ns) ps = sieve' (filter (\x -> rem x p /= 0) ns) (p : ps) sieve' [] ps = reverse ps

That's not the real sieve, though. It doesn't cross off pre-visited primes and is incredibly inefficient. Try finding just the 19th prime. Here is the paper on the real sieve, https://www.cs.hmc.edu/~oneill/papers/Sieve-JFP.pdf

Re: I tried Haskell for 5 years

#177

Post by hzhou321 »

ahakki wrote: post #168
adamwk wrote: post #151

Earlier quoted context omitted.

The Sieve of Eratosthenes is a good example of relatively trivial in imperative code but a research paper in Haskell.

I am pretty sure the sieve can be written like this in Haskell, which might be a bit short for a research paper: sieve :: Integral a => a -> [a] sieve l = sieve' [2..l] [] where sieve' (p:ns) ps = sieve' (filter (\x -> rem x p /= 0) ns) (p : ps) sieve' [] ps = reverse ps

Some ideas on how to make it into a research paper -- add discussion on how do you trivially manage memory (avoid unnecessary allocation and copying and reversing). The original trivia idea was simply to sieve in place. So how do we do that in Haskell (hint: invent something)?

Re: I tried Haskell for 5 years

#178

Post by evincarofautumn »

m-j-fox wrote: post #12

> very hard to understand why a function could be useful in the first place So true. https://hackage.haskell.org/package/base-4.9.1.0/docs/Contro... > mfix :: (a -> m a) -> m a > The fixed point of a monadic computation. mfix f executes the action f only once, with the eventual output fed back as the input. Hence f should not be strict, for then mfix f would diverge. But why tho?

mfix is somewhat low-level. It’s used in the desugaring of Haskell’s “do rec” notation.

I find it useful because it lets me take a recursive structure[1] and a multi-pass algorithm[2] on that structure, which involves side effects[3], and express it in code as a single pass, without mutation.

This conversion of multi-pass algorithms to a single pass while retaining time/space complexity guarantees is one of the key benefits of laziness in general.

[1]: e.g., an AST

[2]: e.g., type inference, where pass 1 is generating type constraints, and pass 2 is solving the constraints and annotating the tree with the final inferred types

[3]: e.g., generating fresh type variables

Re: I tried Haskell for 5 years

#179

Post by sjg007 »

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…

I think Haskell has a future in machine learning.

Re: I tried Haskell for 5 years

#180

Post by nickpeterson »

pivotal wrote: post #132
choxi wrote: post #8

If anyone's curious to try out functional programming, I would highly recommend Elm. I haven't been so excited about a language since I went from C to Ruby ten years ago, and Pragmatic Studios has a great course on it (I have no affiliation): https://pragmaticstudio.com/courses/elm

I spent some time working through various Haskell books with varying success, then decided to do a code challenge (adventofcode.com) using Elm. I didn't finish, but after writing Elm for many days on end, suddenly Haskell clicked a lot more. The Elm compiler is far more friendly than Haskell's and will walk you through a lot of rookie mistakes and oversights. I find Elm exciting, and with the prevalence of React/Redu…

I bought a few Haskell books but could never really grok it. In the last couple years I started learning f# and have found it's an incredible "intro to Haskell" language. I opened one of my Haskell books the other day and realized I understood everything much more quickly.
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