> They rant against and mock everything deemed inferior. They treat people like they're idiots for not understanding basic but unfamiliar principles of the language. And nobody ever seems to shut them down, despite the fact that the majority are pretty welcoming.

I'm happy to try to shut them down but I've pretty much never seen it (perhaps because I'm not in those other communities). If you do, please point me to it. Contact details here: http://web.jaguarpaw.co.uk/~tom/contact/

There were a few big controversies on Twitter and Reddit that I can recall. In one instance in particular, someone called out some Haskell users trying to make Haskell look better by publishing code examples of common algorithms that "cheated" (i.e. the Haskell quicksort that's so popularly paraded around isnt a true quicksort). After the person argued this, they were banned from the Haskell subreddit.

Can you link me to that?

I find it very hard to believe that someone would be banned from the Haskell subreddit for (correctly) pointing out that what has (curiously) entered Haskell lore as Quicksort is not really Quicksort. We all know this.

> Biggest technical problem: lazy evaluation. Other people have said more than enough here.

I am actually wondering about that. It is considered essential by the classic paper "Why functional programming matters", for better program composition.

In particular, I wonder how are you supposed to pass around IO monad (or any other thing whose evaluation will give you side effects) as a value, if you have strict evaluation. I thought the whole point of Haskell was to lazily create a "recipe" as an IO monad, which will then be evaluated after it is returned from function main. In particular, I wonder how Idris deals with this problem, as I read it has strict evaluation.

Laziness and IO are unrelated.

Idris, as you mention, is eager and strict -- and is still pure and uses IO in the same way as Haskell.

Evaluation in Haskell does not cause side-effects, including evaluation of IO action values. It is the execution of these IO actions (by the RTS, due to their inclusion in `main`).

For example:

  let x = map print [1..10] :: [IO ()]

x is just a list of values, each representing the action "print the number N" (for varying N). Evaluating this list doesn't cause printing. Now if you use:

  let y = sequence_ x :: IO ()

You now have another pure value, y, which represents the action to print all the values from 1 to 10. Evaluating y still doesn't cause anything to happen.

main = y

NOW you've actually scheduled the effect denoted by 'y' to execute.

In other words, main is assigned a composition of effects, that by virtue of being inside main, will get executed. This has nothing to do with evaluation order, and when or how these effect descriptions got evaluated.

Ah, OK, thanks for explanation!

> the whole point of Haskell was to lazily create a "recipe" s an IO monad

This "recipe" explanation is one way of explaining how you can think of IO in an impure language. I do wonder if we've taken that explanation too far. I'm pretty sure nobody thinks of it like then when they're actually coding.

Lazy IO's an issue, but Lazy Evaluation? It's not that different from writing SQL, and the places where it is, it's a lot more consistent, predictable, and tuneable. It's usually just bad defaults like Lazy IO, or String instead of Text that get you, but there's some consensus to move away from that.

There are definitely some toxic assholes, as in any community, and it's really shitty if they're going to, e.g., /r/java and harassing people. I feel pretty strongly that the opposite is a more common problem, though, particularly on HN: the anti-intellectualism against functional programmers, and Haskell users in particular, is rampant and gets pretty offensive. Example off the top of my head - https://news.ycombinator.com/item?id=10527745 - article simply explaining a math concept gets, as what was the top comment at the time, a condescending comment calling it all "mental masturbation". I've stopped reading HN so much because it's pretty clear that people trying to learn abstract algebra and apply it to code aren't welcome here.

I don't think people mean to attack you, and it's really difficult for me to understand why the comment you linked could be considered offensive.

I understand you have a certain love for Haskell, and that's a wonderful thing. But not everyone appreciates it as much as you do. One person's artful philosophy is another person's mental masturbation. And both people are entitled to their opinions.

Perhaps you decided to stop reading immediately after you searched for that comment, because you'll see the top reply agrees with your opinion.

There is no "anti-intellectualism" here. There are people who want to get something done at any cost, and there are people who think the journey is more valuable than the destination. Both people have a reason to think they're correct, and neither perspective is any more valuable.

You're on a forum run by a Silicon Valley VC, for goodness' sake. What opinion do you think you'll hear most here? Probably not the same one you'd hear from the wonderful folks on #haskell. It's not "anti-intellectual", it's different.

(also, there are more FP lovers here than you think.)

The grandparent brought up the concept of a community problem where members from a community actively seek out and mock members of another, completely unprovoked. I won't argue whether members of the Haskell community do it or not - I haven't seen it, maybe I've just missed it, but it's terrible if they do. Whether you think it's a particularly good example or not, I'm merely pointing out that it happens a fair bit in the other direction here on HN, and the community either supports or turns a blind eye to it.

That's what's obnoxious about that comment - it's completely unprovoked trolling, and yet it was heavily upvoted. Of course the first reply disagrees with it - If I go to a thread about a Ruby library and insult people for wanting to use Ruby, you'd expect the top reply to disagree. What you'd hope not to see is for that trolling comment to be overwhelmingly upvoted to the top, and for the community to be making excuses as to why in this instance it's ok.

If someone's not interested in some content, or disagrees with it, that's one thing, but to actively find, mock, and seek community support in ostracizing people who are interested in learning it because of that interest - I'd argue that's anti-intellectual by definition. But whatever you want to call it, it's, as the grandparent comment stated, a community problem. Sadly for the author of that comment, the HN community excuses that sort of behavior - it's just different from the wonderful folks in whatever language community they're used to.

In my opinion, Haskell community was very warm and helpful, and also able to admit shortcomings.

This was before Stack Overflow reshaped the landscape. On Freenode, ##java was a pretty hostile place (having to deal with people asking to do homework for them or being overall clueless) with attitude "if you see a problem with Java, the problem is you". The culture was so toxic that "forces of evil" ended up stealing the channel from under its original founder and banning him.

On #haskell, you would be immersed in polite chat revealing the development in all things FP, plus even pretty stupid questions were answered in such way that they enlightened both the asking person and bywatchers.

Also they had quite a few awesome bots that let anyone practically develop directly in IRC.

> In my opinion, Haskell community was very warm and helpful, and also able to admit shortcomings.

I just wanted to second this. On a whim, I started attending various community events in/around NYC a few years ago, knowing next to nothing about the language, and found _everyone_ (no exaggeration) I interacted with, saw present, etc. to be welcoming, helpful and encouraging.

To be fair it doesn't make a lot of sense to march into #java for the purpose of bitching about how you don't like java. That's just trolling.