6 ms·

Hacking Haskell

16 points by DanielRibeiro 15y ago

alanthonyc 15y ago
I've been going through the "Learn You a Haskell..." book for the past week or so (mainly to procrastinate on my main project). After the first few chapters which basically just show the syntax for things you might do in other languages (e.g. lambdas, maps, recursion, etc.), I've gotten to stuff that's new to me (mainly type classes, though I'm sure there's more) and I'm sort of getting blown away by the possibilities.
- gtani 15y ago
  Learn You is terrific. Besides that, Conrad Barski and Hal Daume's tutorials, the stuff that the Wash U students did (see Haskell Wiki), and Hutton's little green book. http://www.haskell.org/haskellwiki/Tutorials http://www.haskell.org/haskellwiki/Tutorials
dons 15y ago
The "always just out of reach" metaphor is tired. It's a somewhat outdated view of the community, which is now quite large, with many members gainfully employed building systems in Haskell commercially, and in non-trivial applications.
ggchappell 15y ago
I'd have to say that his arguments are interesting, but they only work well with carefully chosen examples. In particular, the question of efficiency in the context of lazy evaluation appears to be very tricky, and thus far it has been only little explored. For example, the first way to do large-scale I/O in Haskell that doesn't eat up resources (namedly, "iteratees") is maybe 3 years old, and I don't think an awfully lot of people really grasp it. No, it seems to me that we're just beginning to figure this stuff out. Earlier comment: Talk about just out-of-reach, how about the words on the page? Viewing this under FF3.6 on Snow Leopard, and the words go just off the right-hand side of the window, no matter what size I make it. EDIT: Tried Safari. It's a fixed-width column there. And Readable works fine under FF.
- dons 15y ago
  There seems to be some confusion here. Iteratees weren't introduced to solve the problem of "eating up resources" per se. They're a new abstraction for doing high performance IO -- in any language. You've always had several choices for IO in Haskell: lazy IO (like pipes in shell programming), or strict IO (like say, Python or C IO). Iteratees blend these somewhat, giving a third way. So you could say that IO isn't well explained by computer science yet -- as new approaches are still being discovered. That doesn't really say anything about Haskell, other than it was the first developer community to really take iteratee-style IO seriously.
  - ggchappell 15y ago
    Well, perhaps I am one of the many who don't really grasp iteratees. In any case, my point about efficiency in the context of lazy evaluation not being well understood, still stands.
    - dons 15y ago
      Yes, the space semantics of lazy evaluation is difficult to learn, particularly when coming from fully-strict languages, or languages with little support for lazy programming. Many other programming techniques face similar barriers: e.g. memoization, concurrency or logic programming result in similar brain twisting -- yet can be suprisingly useful. So I argue that programmers shouldn't be scared of technology -- embracing and learning new techniques can only improve your practice.
  - parfe 15y ago
    >So you could say that IO isn't well explained by computer science yet I don't think I could ever be sold on using a language where IO is an unsolved problem. Computer Science has defined it quite well for me in Python
    - Peaker 15y ago
      Python doesn't really have the equivalent power of Iteratees. Iteratees let you compose chains of highly-efficient producers, transformers and consumers. As a relatively trivial example, how would you write something in Python that performs this: for word in open("really_big_file", "rb").read().split(","): socket.send(word[::-1]) but does so with acceptable performance and memory use?
baguasquirrel 15y ago
I've actually been trying to prove people like this guy wrong for years. My takeaway is that Haskell is not the problem. The real problem is that solving people's problems is hard. Designing and iterating on a product or service is hard. Finding and involving the ambitious folks with halfway well-baked ideas is hard. Now I'm going to get a lot of flack here for saying this but I simply just don't feel that most of the stuff we make today is of particularly high craftsmanship. We need one of two things to happen. The first is that the demand for thoroughly well-crafted software has to increase. But that much is out of our hands as it is conditional on the public at large. This will happen eventually. New tech starts life as a toy. At some point, people will want those toys to be reliable. Going the other way, we could make it more rewarding for people to build scalable, maintainable systems in Haskell. But we are already well on the way to doing this. For example, Snap was much easier to use than Happstack (IMHO), and Happstack itself has already much improved over the years. The libraries for Couch and Mongo are as good as any other. Tools aside then, Haskell's main impediment is that can be a bit intimidating. But a friendly and openminded developer community can go a long way. We just have to keep this in mind, and keep fostering projects.
- szany 15y ago
  cf. http://conal.net/blog/posts/can-functional-programming-be-liberated-from-the-von-neumann-paradigm/ http://conal.net/blog/posts/can-functional-programming-be-li...
szany 15y ago
"I listen closely for the subtle misunderstandings that are inevitably lurking underneath this newly-minted zealotry. And I am seldom disappointed." Can anyone elaborate?

16 points by DanielRibeiro 15y ago

I've been going through the "Learn You a Haskell..." book for the past week or so (mainly to procrastinate on my main project). After the first few chapters which basically just show the syntax for things you might do in other languages (e.g. lambdas, maps, recursion, etc.), I've gotten to stuff that's new to me (mainly type classes, though I'm sure there's more) and I'm sort of getting blown away by the possibilities.

gtani 15y ago
Learn You is terrific. Besides that, Conrad Barski and Hal Daume's tutorials, the stuff that the Wash U students did (see Haskell Wiki), and Hutton's little green book. http://www.haskell.org/haskellwiki/Tutorials http://www.haskell.org/haskellwiki/Tutorials

dons 15y ago

The "always just out of reach" metaphor is tired. It's a somewhat outdated view of the community, which is now quite large, with many members gainfully employed building systems in Haskell commercially, and in non-trivial applications.

ggchappell 15y ago

I'd have to say that his arguments are interesting, but they only work well with carefully chosen examples. In particular, the question of efficiency in the context of lazy evaluation appears to be very tricky, and thus far it has been only little explored. For example, the first way to do large-scale I/O in Haskell that doesn't eat up resources (namedly, "iteratees") is maybe 3 years old, and I don't think an awfully lot of people really grasp it. No, it seems to me that we're just beginning to figure this stuff out. Earlier comment: Talk about just out-of-reach, how about the words on the page? Viewing this under FF3.6 on Snow Leopard, and the words go just off the right-hand side of the window, no matter what size I make it. EDIT: Tried Safari. It's a fixed-width column there. And Readable works fine under FF.

dons 15y ago
There seems to be some confusion here. Iteratees weren't introduced to solve the problem of "eating up resources" per se. They're a new abstraction for doing high performance IO -- in any language. You've always had several choices for IO in Haskell: lazy IO (like pipes in shell programming), or strict IO (like say, Python or C IO). Iteratees blend these somewhat, giving a third way. So you could say that IO isn't well explained by computer science yet -- as new approaches are still being discovered. That doesn't really say anything about Haskell, other than it was the first developer community to really take iteratee-style IO seriously.
- ggchappell 15y ago
  Well, perhaps I am one of the many who don't really grasp iteratees. In any case, my point about efficiency in the context of lazy evaluation not being well understood, still stands.
  - dons 15y ago
    Yes, the space semantics of lazy evaluation is difficult to learn, particularly when coming from fully-strict languages, or languages with little support for lazy programming. Many other programming techniques face similar barriers: e.g. memoization, concurrency or logic programming result in similar brain twisting -- yet can be suprisingly useful. So I argue that programmers shouldn't be scared of technology -- embracing and learning new techniques can only improve your practice.
- parfe 15y ago
  >So you could say that IO isn't well explained by computer science yet I don't think I could ever be sold on using a language where IO is an unsolved problem. Computer Science has defined it quite well for me in Python
  - Peaker 15y ago
    Python doesn't really have the equivalent power of Iteratees. Iteratees let you compose chains of highly-efficient producers, transformers and consumers. As a relatively trivial example, how would you write something in Python that performs this: for word in open("really_big_file", "rb").read().split(","): socket.send(word[::-1]) but does so with acceptable performance and memory use?

baguasquirrel 15y ago

I've actually been trying to prove people like this guy wrong for years. My takeaway is that Haskell is not the problem. The real problem is that solving people's problems is hard. Designing and iterating on a product or service is hard. Finding and involving the ambitious folks with halfway well-baked ideas is hard. Now I'm going to get a lot of flack here for saying this but I simply just don't feel that most of the stuff we make today is of particularly high craftsmanship. We need one of two things to happen. The first is that the demand for thoroughly well-crafted software has to increase. But that much is out of our hands as it is conditional on the public at large. This will happen eventually. New tech starts life as a toy. At some point, people will want those toys to be reliable. Going the other way, we could make it more rewarding for people to build scalable, maintainable systems in Haskell. But we are already well on the way to doing this. For example, Snap was much easier to use than Happstack (IMHO), and Happstack itself has already much improved over the years. The libraries for Couch and Mongo are as good as any other. Tools aside then, Haskell's main impediment is that can be a bit intimidating. But a friendly and openminded developer community can go a long way. We just have to keep this in mind, and keep fostering projects.

szany 15y ago
cf. http://conal.net/blog/posts/can-functional-programming-be-liberated-from-the-von-neumann-paradigm/ http://conal.net/blog/posts/can-functional-programming-be-li...

szany 15y ago

"I listen closely for the subtle misunderstandings that are inevitably lurking underneath this newly-minted zealotry. And I am seldom disappointed." Can anyone elaborate?