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Running a Startup on Haskell

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Re: Running a Startup on Haskell

#21

Post by zura »

jamwt wrote: post #18
jsdalton wrote: post #14

Does Haskell offer any tangible, practical advantages or benefits over other languages in the context of a web framework, aside from just "if you prefer a functional style of programming and you're working on a web project, here's a way to do it"? I'd love for somebody to convince me why a Haskell approach to web frameworks is superior to Python/PHP/Ruby/JS beyond the usual "it's a matter of taste" argument.

Haskell's advantages (and disadvantages) as a Web Framework are generally the same as in any other application domain: performance, concurrency, and correctness.

While I agree regarding correctness and concurrency, I wouldn't emphasize performance, even for Java and .NET, whose GCs are more developed, tuned and tested in the production environment than Haskell's one.

Edit: And for Haskell, achieving needed performance can be quite tricky with regard to its laziness.

Re: Running a Startup on Haskell

#22

Post by jamesbritt »

zura wrote: post #21
jamwt wrote: post #18

Earlier quoted context omitted.

Haskell's advantages (and disadvantages) as a Web Framework are generally the same as in any other application domain: performance, concurrency, and correctness.

While I agree regarding correctness and concurrency, I wouldn't emphasize performance, even for Java and .NET, whose GCs are more developed, tuned and tested in the production environment than Haskell's one. Edit: And for Haskell, achieving needed performance can be quite tricky with regard to its laziness.

There was some discussion on HN about the Snap Web framework benchmarks relative to some other frameworks: http://news.ycombinator.com/item?id=1380405

No .Net in there, though.

Re: Running a Startup on Haskell

#23

Post by microtonal »

zura wrote: post #21
jamwt wrote: post #18

Earlier quoted context omitted.

Haskell's advantages (and disadvantages) as a Web Framework are generally the same as in any other application domain: performance, concurrency, and correctness.

While I agree regarding correctness and concurrency, I wouldn't emphasize performance, even for Java and .NET, whose GCs are more developed, tuned and tested in the production environment than Haskell's one. Edit: And for Haskell, achieving needed performance can be quite tricky with regard to its laziness.

Edit: And for Haskell, achieving needed performance can be quite tricky with regard to its laziness.

But Snap is driven by enumerators/iteratees (via the enumerator package), which make it much easier to do fast near-constant space IO.

I have built a web application that uses Snap to query large (parse) treebanks, and it was easy to make it performant.

Re: Running a Startup on Haskell

#24

Post by supersillyus »

jsdalton wrote: post #14

Does Haskell offer any tangible, practical advantages or benefits over other languages in the context of a web framework, aside from just "if you prefer a functional style of programming and you're working on a web project, here's a way to do it"? I'd love for somebody to convince me why a Haskell approach to web frameworks is superior to Python/PHP/Ruby/JS beyond the usual "it's a matter of taste" argument.

For one, GHC gives you M:N threads with the runtime handling the async IO under the hood, making it possible to write code in a simple blocking style while still getting use of all your cores and having fast IO. This is also true for Erlang, Go, and a few others, though, and it's not terribly relevant for lots of simple web code, but it is a practical advantage.

Re: Running a Startup on Haskell

#25

Post by microtonal »

viscanti wrote: post #5
antipax wrote: post #2

Haskell web frameworks are maturing rapidly and the language is a joy to work in, once you learn how to approach problems in it. Haskell has probably not reached the peak of it's popularity yet (and frankly it's overdue for some mainstream love).

I think Haskell (and functional languages in general) will become increasingly popular as it is (they are) a powerful way to deal with concurrency and can easily take advantage of multiple processors. Languages are tools in a developers toolbox, and Haskell turns out to be a powerful one for several growing problems.

It's not just that. Haskell has exceptionally strong typing and containment of mutable computations, making it much easier to write correct programs. When a module compiles, it's usually pretty bug-free.

Re: Running a Startup on Haskell

#26

Post by pbz »

microtonal wrote: post #25
viscanti wrote: post #5

Earlier quoted context omitted.

I think Haskell (and functional languages in general) will become increasingly popular as it is (they are) a powerful way to deal with concurrency and can easily take advantage of multiple processors. Languages are tools in a developers toolbox, and Haskell turns out to be a powerful one for several growing problems.

It's not just that. Haskell has exceptionally strong typing and containment of mutable computations, making it much easier to write correct programs. When a module compiles, it's usually pretty bug-free.

How does the strong typing compare with Java/C#? Thanks.

Re: Running a Startup on Haskell

#27

Post by tikhonj »

pbz wrote: post #26
microtonal wrote: post #25

Earlier quoted context omitted.

It's not just that. Haskell has exceptionally strong typing and containment of mutable computations, making it much easier to write correct programs. When a module compiles, it's usually pretty bug-free.

How does the strong typing compare with Java/C#? Thanks.

Several things jump out immediately:

  - Haskell has exceptionally thorough type inference (almost all type declarations are optional).
  - anything impure (e.g. involving an I/O) is typed as such
  - the types are easier to read and tend to give a good idea of what the function in question is doing
  - much more complicated types are readable
  - idioms like Monads lead to a lot of code that is much more abstract and generic than anything I've seen in Java. There are tons of library functions that can work on lists, or IO things, or parsers, or random values...
Some things that I found particularly cool in Haskell: - functions (and even constants!) can be polymorphic on their return type. The function read, for example, always takes in a String but returns whatever type you happen to need. - You can easily express things like a "list of list": [[a]]. I don't even know how to begin writing a function like join in Java. (On lists, join takes a list of lists of something and flattens it.)

Overall, I've found Haskell's type system to be much more useful, and much less of a burden, than Java's.

That said, I'm just a college student with limited experience with either language. I've used Java more than Haskell but I've been using the latter more recently; I've never used C#.

Re: Running a Startup on Haskell

#28

Post by skybrian »

tikhonj wrote: post #27
pbz wrote: post #26

Earlier quoted context omitted.

How does the strong typing compare with Java/C#? Thanks.

Several things jump out immediately: - Haskell has exceptionally thorough type inference (almost all type declarations are optional). - anything impure (e.g. involving an I/O) is typed as such - the types are easier to read and tend to give a good idea of what the function in question is doing - much more complicated types are readable - idioms like Monads lead to a lot of code that is much more abstract and generic…

Maybe it's better with more experience or when you're reading your own code, but I find that reading a Haskell program is often like reading a math paper - you can't skim it; you have to slow way down and study it, one line at a time, and look up the definition of each term as you go and think about what it means, and try out simple examples. And sometimes you don't have the background to understand the underlying concepts, so you have to study a prerequisite first.

So I think to like Haskell, you have to truly believe that more abstraction is better. It's very much a mathematician's language.

The thing is, when writing code, I don't want to write a math paper. When I'm done, I want it to be as smooth and easy to read and as obvious as an article in the New Yorker.

Re: Running a Startup on Haskell

#29

Post by jerf »

jsdalton wrote: post #14

Does Haskell offer any tangible, practical advantages or benefits over other languages in the context of a web framework, aside from just "if you prefer a functional style of programming and you're working on a web project, here's a way to do it"? I'd love for somebody to convince me why a Haskell approach to web frameworks is superior to Python/PHP/Ruby/JS beyond the usual "it's a matter of taste" argument.

"Does Haskell offer any tangible, practical advantages or benefits over other languages in the context of a web framework, aside from just "if you prefer a functional style of programming and you're working on a web project, here's a way to do it"?"

At the moment, my answer is "Not yet, but ask again in a year." There are tons of interesting things happening in the area of letting you have "performance, correctness, rapid development and prototyping, pick three", but they're still in the early phases yet.

Re: Running a Startup on Haskell

#30

Post by jerf »

skybrian wrote: post #28
tikhonj wrote: post #27

Earlier quoted context omitted.

Several things jump out immediately: - Haskell has exceptionally thorough type inference (almost all type declarations are optional). - anything impure (e.g. involving an I/O) is typed as such - the types are easier to read and tend to give a good idea of what the function in question is doing - much more complicated types are readable - idioms like Monads lead to a lot of code that is much more abstract and generic…

Maybe it's better with more experience or when you're reading your own code, but I find that reading a Haskell program is often like reading a math paper - you can't skim it; you have to slow way down and study it, one line at a time, and look up the definition of each term as you go and think about what it means, and try out simple examples. And sometimes you don't have the background to understand the underlying co…

"When I'm done, I want it to be as smooth and easy to read and as obvious as an article in the New Yorker."

Your metaphor is apt; if your code is going to be that smooth, you need to learn Haskell to the same extent you know English for the New Yorker. The Internet suggests that the New Yorker is written for a "10th grade reading level", but of course the average American has between an 8th or 9th grade level.

It does get easier with practice to read the language, and what's left after that is whatever core difficult the code being expressed has regardless of the target language, the essential difficulty. Haskell can hardly be blamed for bringing that to the foreground where other languages stuff it in the background.

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