Nice synopsis of Haskell as a language, but it doesn't touch on why they chose it for server side web application programming, specifically. I'd be interested in knowing if it's capable, scalable and stable enough to provide a platform to build on for the next few years. Based on its history to date, are there protections in place for backwards compatibility, or are they likely to end up pinning to an obsolete version? Does the standard library support web services (SSL, unicode, etc.), or will they need to turn to third parties or code essential building blocks from scratch?
One thing worth noting here is that the article dates from 2009; things have improved a lot since then vis a vis web development in Haskell. New frameworks (Snap, Yesod) have sprung up, and the library and toolchain support have improved immeasurably.
To answer some of your questions a little more directly (I hope someone like dons with a more encyclopaedic knowledge can pitch in here):
* As a language, Haskell is both very stable and very cutting-edge. This is because GHC (the only Haskell compiler people use seriously for production, at least as far as I'm aware) supports both the Haskell '98 standard, and the more recent Haskell 2010 standard—but it also supports a large number of language extensions [1] such as type families, existential types, GADTs etc. So
* In terms of scalability, some of the recent benchmarks for Haskell-based web servers have been very impressive. Whether or not this translates into real-world performance is something we'll see as more people start using them in production. Recent improvements to the GHC I/O manager make the case for Haskell more compelling in this regard than it used to be.
* It's pretty easy in Haskell to write wrappers around C libraries, such as OpenSSL. There are also moves to implement more of these core parts of any web stack in pure Haskell, although getting them to feature-completion is a process that will take time.
A couple of recent reads spring to mind: a Stack Overflow discussion [1] where Alex Payne asked about Haskell tools to make programs production-ready, and Johan Tibell's article [2] on which Haskell libraries one should use.
Further proof of my theory that GHC's license has a clause buried in it stating that you must post an explanation of monads on your blog in order to use it.
I'm not sure whether you are serious, cynical or tongue-in-cheek, so I feel it necessary to point out that they are not actually explaining monads. They provide an answer to the question that everyone will ask: "how do you do I/O in a language in which all computations are supposed to be free of side-effects, when I/O is obviously a side-effect?" The answer to that question is 'monads', but that's as far as they go. They don't actually explain anything about monads.
"And most of all, Haskell makes programming fun!" - If you're doing a startup make sure you choose a language you enjoy. You're going to be spending a lot of time using it.
(Also applies to cofounders and the application itself.)
I was gonna quote exactly the same, to affirm this. Haskell is an absolute joy to program in. Nothing in the code of a Haskell program feels like "extra" or "too much".
It never ceases to amaze me how few people forget to take this into account when choosing technologies and focus strictly on what's practical. The best route is usually to choose something that's fun and practical.
(and before someone corrects me, yes I know sometimes you can't do that, and yes I know that in that situation you usually have to choose practicality over fun)
The most important sentence for me was "Two of us (me and Sebas) are enrolled in the Software Technology master program at Utrecht University, where we often use the programming language Haskell."
What you're familiar and comfortable with is one of the most important considerations in language/platform choice.
Thank God. An article advocating Haskell that doesn't descend into some variant of "You will go to Hell if you aren't using a strongly-typed, pure, and lazy programming language."
Predictably, this blog post reads like a Haskell pamphlet and it hits all the Bingo marks: purity, no side effects, ah but yes side effects with the IO monads, monads, concurrency, the awesome community (seriously? Have they actually looked into it? The #haskell irc channel is moderated by Tony Morris, a lunatic who's been banned from many mailing-lists and channels because of several psychological disorders he suffers from), etc...
Even more predictably, not a single word on more pragmatic reasons to choose Haskell as a startup, such as: web and networking support, logging, database access, etc...
The odds of a startup succeeding are already vanishingly small, why make it even harder on yourself by picking an exotic language that's all but unknown in the work force?
"Haskell has no side effects" is true, but only in the sense that they are no longer side effects but simply "effects" as they are marked a such.
The idea isn't to get rid of effects but to quarantine them, separate them from simple functions into "procedures". This means you get to have real functions in Haskell, and they truly are easier to compose together than what other languages call "functions" but are actually procedures.
As for concurrency, Haskell is really in a unique spot, where you can get the performance of threads and the simplicity of processes: the immutability of everything not explicitly created for inter-thread communication gives you the same safety of IPC, but the shared memory gives you threads' performance.
I think the benefits outlined on the page may not be specific to web development, but they definitely apply to it too.
I haven't seen Tony Morris abuse anyone in the community, and the IRC channel is an amazing combination of immense knowledge and patience with newbies.
> I haven't seen Tony Morris abuse anyone in the community, and the IRC channel is an amazing combination of immense knowledge and patience with newbies.
Seriously? Here is the latest example on scala-debate, just two months ago, where he went so far off the deep end that Martin himself had to step in and tell him to cool down:
He dishes this kind of abuse on a regular basis on lists, irc (especially #scala) and sometimes even on his own Twitter feed.
Anyway, back to the topic at hand: yes, I know the theory behind immutability and isolation and how it can enable easier parallelism. I have yet to see practical examples of that in Haskell and convincing stats that show a boost in performance compared to more traditional approaches (such as Java+nio or even Scala actors).
My questions still hold regarding Haskell's adequacy in production, e.g. with regards to database, logging or continuous integration, and I'm not the only one: Alex Payne recently expressed the same concerns on SO:
Yes, but nothing like that is happening in #haskell. I've asked some really stupid questions there, sometimes more than once, and been treated well. The "worst" treatment I've received is an admonishment to read the Haskell site for a more trivial question.
There are 16 official moderators on the #haskell channel, as well. I apologize (as one of those moderators) if the OP has had a bad experience: with so many people in the channel, not everyone gets exactly what they need, however, we do try very very hard to be friendly.
Having never met Tony, but having read many of his posts and comments, I have to say that I can understand that people develop a severe dislike towards him. He's emphatically not a 'nice guy' online. He is expert at his stuff and that makes up for a lot, but he would have to have more respect for, and patience with, less knowledgeable folks to become 'a very good teacher'.
He is extremely condescending towards those that don't get it, especially when they don't display sufficient humility about their lack of knowledge. You have to go "I'm sure you're right, but I would think that you could do such-and-such" to avoid pissing him off. As soon as you say "I think that's wrong, because of this-and-that", then you run the risk to get shat all over with comments of the "you don't get it and you don't want to learn"-kind, even though you're engaging in conversation that wouldn't lead to a flamewar with most other people.
He is a decent teacher for those that can look past his purist rants and are sophisticated enough to ignore the antagonizing that's going on, but he could do much to disseminate his knowledge more effectively to a wider public, without losing anything of the value of his message. It's an awful waste :/.
PS: This is why I sometimes demonstrate low tolerance for stupidity and/or failure or refusal to entertain the possibility of thinking. People get hurt. No, I am not sorry.
(for context he is very good at squash and hurt himself while playing)
What happened to him is very unfortunate but see the kind of conclusion he draws from his ordeal:
"I have formed the opinion that medical specialists are no more equipped to make a medical diagnosis than lay-people."
You would think someone with a reasonable intellect would refrain from making such sweeping generalizations, especially when their own judgment has been clouded by negative empirical evidence.
It's a personal attack, but not actually an ad hominem attack. There is a difference between "McDonalds has a bad business model because their burgers are gross" and "McDonalds is unpleasant to eat at because their burgers are gross." The poster's attack is of the second form.
Still fallacious. To continue your analogy, this is like saying that all McDonald's stores have unpleasant food because of that one store. Yes, something should be done if it wasn't a one time thing, but no that does not mean the other stores necessarily have the issue(although they could).
