Re: [Haskell-cafe] Toy application advice wanted
On Wednesday 05 May 2004 04:46, Ben Lippmeier wrote: http://www.haskell.org/libraries and look at how many seperate GUI libraries there are - I counted 16 - then ask what made the developer for the 16th one choose to start over. The fact that the 16th one is a wxwindows binding justifies this quite well :) V. -- Si puo' vincere una guerra in due e forse anche da solo si puo' estrarre il cuore anche al piu' nero assassino ma e' piu' difficile cambiare un' idea [Litfiba] ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Toy application advice wanted
On May 3, 2004, at 5:52 PM, [EMAIL PROTECTED] wrote: I've got an interesting task this week for my job. (Note that this will undoubtably last for longer than a week). I'm evaluating several high-level languages as development vehicles for our next suite of applications. The languages I'm currently considering are Scheme, Erlang, and Haskell... The toy application I've designed for myself is a simple GUI-based app that can load a Sun .au format sound file, display its waveform in a window, perform some simple filtering, play the sound for the user, and then save the changed sound file back out to disk. If I get familiar enough with the respective environments I'd like to add zooming in/out and scrolling to the waveform display... I have an amortized four days (32 hours!!!) to implement this simple application in Haskell... Any advice/pointers/flames welcome. Thanks in advance. Frankly, I think it's completely unrealistic to expect to be able to fairly evaluate Haskell in 32 hours. As you noted yourself, Scheme and Erlang, being strict, are much closer to conventional programming languages than Haskell is, so it's easier to transfer skills to them. Furthermore, they're untyped, and learning how to exploit Haskell's static typing is one of the bigger hurdles to learning how to exploit Haskell. Even if, as you wrote in a later post, you lower your sights to something less ambitious than a full-blown GUI app (which I think is a good idea), it's hard get a grasp on concepts like laziness, recursive datatypes, parametric polymorphism, monads, type classes and so on in less than a week, even for experienced programmers. At best, I imagine you'll come away curious and hungry for more; but clearly that doesn't suffice for a language evaluation. Of course, the fact that Haskell can't be grasped in a day (or week) can be construed as a practical argument against its adoption. On the other hand, if you accept that there's no such thing as a free lunch, you might consider that a merit; what is the point of adopting a new language if it doesn't change the way you think about programming, and let you write old programs in new, perhaps better, ways? [1] While Haskell is IMO the best programming language around, and I want to encourage its broader adoption, if you want a well-designed language with good implementation and support which permits swifter skill transfer, may I (strongly) recommend you add Objective Caml to your list of candidates? Once you acquire some experience with an ML-like language such as OCaml, which after all resembles Haskell in many ways, you will, I believe, find yourself better equipped to evaluate Haskell. Regards, Frank [1] Think about polynomials and real numbers. Complex numbers were, I believe, invented specifically to ensure that every polynomial equation has a solution. So, to address some problems, we need to take a step backward before we can take one forward. ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Toy application advice wanted
I'm finding wxHaskell very nice, and a wxWidgets binding is something many other advanced languages don't have (even OCaml). The only downside is having a 'Hello World' GUI application with 7 Mb... but it runs quite well and smooth once it's loaded. --- []s, Andrei de A. Formiga --- Vincenzo aka Nick Name [EMAIL PROTECTED] wrote: The fact that the 16th one is a wxwindows binding justifies this quite well :) V. __ Do you Yahoo!? Win a $20,000 Career Makeover at Yahoo! HotJobs http://hotjobs.sweepstakes.yahoo.com/careermakeover ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Toy application advice wanted
David Roundy wrote: I think that sounds like a good idea (not doing a GUI just yet) but would recommend that perhaps you could do something pretty impure in terms of file or directory browsing. That wouldn't involve going beyond the standard libraries, but might give you some idea of the expressive power of the languages in terms of IO actions. I'm thinking something like a recursive grep, or wc -l... except preferably a bit more tailored to the sort of IO you'll have to do in your actual application. I guess the trick would be in finding something tough enough, since wc -l would be something like a two-liner... A one-liner: main = interact (show . length . lines) - Lyle Kopnicky ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Toy application advice wanted
On Wed, 5 May 2004, Frank Atanassow wrote: Frankly, I think it's completely unrealistic to expect to be able to fairly evaluate Haskell in 32 hours. As you noted yourself, Scheme and Erlang, being strict, are much closer to conventional programming languages than Haskell is, so it's easier to transfer skills to them. Yeah, I'm starting to see the difficulty in recommending a language I can barely dabble in up the chain (not as bad as pointy hair bosses, but still not computer scientists). Furthermore, they're untyped, and learning how to exploit Haskell's static typing is one of the bigger hurdles to learning how to exploit Haskell. That was one of the things that attracted me to Haskell...the type system. I enjoyed strong typing in ML when I played with it in college. At best, I imagine you'll come away curious and hungry for more; but clearly that doesn't suffice for a language evaluation. Certainly. Of course, the fact that Haskell can't be grasped in a day (or week) can be construed as a practical argument against its adoption. On the other hand, if you accept that there's no such thing as a free lunch, you might consider that a merit; what is the point of adopting a new language if it doesn't change the way you think about programming, and let you write old programs in new, perhaps better, ways? [1] This is the crux of the argument. I don't understand how we can make good programming languages more popular. My son was born just a couple of weeks ago, and I barely have enough time now to keep up with anything in my career/field; I was lucky I convinced my management to let me do a (too-) brief language survey. But without having thought in Haskell for at least a couple of months, how can I hope to promote it successfully? How can I get a couple of months proficiency in Haskell unless I've promoted it successfully? (Co-routines? =) While Haskell is IMO the best programming language around, and I want to encourage its broader adoption, if you want a well-designed language with good implementation and support which permits swifter skill transfer, may I (strongly) recommend you add Objective Caml to your list of candidates? Once you acquire some experience with an ML-like language such as OCaml, which after all resembles Haskell in many ways, you will, I believe, find yourself better equipped to evaluate Haskell. Thanks for this...I actually just added ocaml to my list last night. I was looking over the programming languages shootout and read some of the source. It looks pretty neat. I spent last night writing a simple object system from scratch in Scheme with macros, and starting thinking about all the things I'd have to do to implement any kind of type safety, and it just sort of clicked that ocaml might be an interesting solution. Thanks again for your comments (and everyone's). -- Mike J. BellThis is all just my opinion. Outside of a dog, a book is man's best friend. Inside it's too dark to read. [EMAIL PROTECTED] ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] HDirect, [unique], troubles again!
In my quest for a fuse binding for Haskell, which I really need at the
moment, I have the following definition working:
module HSFuse {
interface stat{};
typedef int getattrT([string] char *,stat);
typedef struct fuseOps {
[ref] getattrT * getattr;
} fuseOps;
void fuse_main(int argc,[in,string,size_is(argc)]char** argv,[ref]
fuseOps * op);
};
but when I substitute ref with unique, because some operations can
be null, I get the errors below. The problem is that in the generated
hs file there is
data FuseOps = FuseOps {getattr :: GetattrT}
which completely ignores my type declaration! Did I do something wrong?
Commands invoked and errors follow, thanks for attention:
ihc -fhs-to-c -fuse-ints-everywhere -c HSFuse.idl
ghc -package hdirect -fglasgow-exts HSFuse.hs -c
HSFuse.hs:136:
Couldn't match
`GHC.Base.String - Stat - GHC.IOBase.IO GHC.Base.Int'
against
`GHC.Ptr.Ptr
(GHC.Base.String - Stat - GHC.IOBase.IO GHC.Base.Int)'
Expected type: GHC.Ptr.Ptr
(GHC.Ptr.Ptr
(GHC.Base.String - Stat -
GHC.IOBase.IO GHC.Base.Int))
- GHC.Ptr.Ptr
(GHC.Base.String - Stat - GHC.IOBase.IO
GHC.Base.Int)
- GHC.IOBase.IO ()
Inferred type: GHC.Ptr.Ptr
(GHC.Ptr.Ptr
(GHC.Base.String - Stat -
GHC.IOBase.IO GHC.Base.Int))
- (GHC.Base.String - Stat - GHC.IOBase.IO
GHC.Base.Int)
- GHC.IOBase.IO ()
In the second argument of `HDirect.writeunique', namely
`writeGetattrT'
In the definition of `writeFuseOps':
writeFuseOps ptr (FuseOps getattr)
= let
pf0 = ptr
pf1 = HDirect.addNCastPtr pf0 0
in
HDirect.writeunique (HDirect.allocBytes
(GHC.Real.fromIntegral sizeofGetattrT))
writeGetattrT
pf1
getattr
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