On Thursday 16 September 2004 20:27, Andy Moran wrote:
> I'd like to say that this approach has worked for us time and time
> again, but, to date, we've never had to rewrite a slow component in C
> :-) For us, C interoperability has always been a case of linking to
> third party software, or for w
Again, I will try to take benefit of the thread on the "senior" list to
ask a question to everybody who uses haskell in industry (so you people
at Galois Connection can't avoid to answer, I know you are there :D ):
are your solutions entierely written in haskell, or are there parts
written in o
On Saturday 08 May 2004 13:16, Sven Panne wrote:
> Apart from that, having a binding for SDL would be nice, too, and
> somebody is already working on it, IIRC.
I would like to try these bindings.
V.
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On Thursday 06 May 2004 16:10, Vincenzo aka Nick Name wrote:
> [hide] unsigned
oh yes, I know, [hide] does not exist in hdirect but this does not
change things :)
V.
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On Thursday 06 May 2004 13:36, Vincenzo aka Nick Name wrote:
> Can greencard support callbacks? If yes, can someone provide a simple
> example?
Ok, I finally found Alistair Reid's tutorial, which I forgot to read
again, and well, I see that greencard does not support callbacks. My
a
I realize that I myself might have already asked this question to some
of you, but I am really confused now. Can I have some opinion on "what
is the right way to implement callbacks from C to haskell"? Will I have
to learn the FFI and stop it, or is there some tool to automate the
process? I ne
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
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 thi
Hi all,
I am experimenting with hdirect for the first time, and I can't figure
out how to call an haskell function of type String -> IO Int from C. I
already can compile and use a function of type Char -> IO Int, so I
assume to be using the right command line arguments.
I have, in Math.idl
--
Alle 19:13, giovedì 5 febbraio 2004, Glynn Clements ha scritto:
> > - concatenate file paths
>
> (concat . intersperse "/")
>
> Maybe you wanted something more, e.g. canonicalisation?
>
Yes, maybe an interface to realpath(3) is what I really need.
> > - tell if a path is absolute or relat
Hi all,
I am so often in need for this (I suppose, non-existing) module, that I
am going crazy :) I have found discussions in the archives for haskell
mailing lists, but is there any, even posix-only, even unix-only, but
better portable, implementation of functions to
- concatenate file path
I seem to recall a discussion, don't know if it was here or on
comp.lang.functional, where somebody said he uses haskell to generate
fortran code.
That fascinated me a lot, because that would mean being able to generate
a program already specialized for a specific input, by first reading
input
Hi all, I am trying to lear more about arrows in haskell, so I am
reading the paper at:
http://www.soi.city.ac.uk/~ross/papers/fop.html
However, I can't understand how to produce a working and meaningful
example of the trace function, or the loop arrow (I am using the
"automata" example).
The
Alle 20:07, lunedì 15 settembre 2003, Sven Panne ha scritto:
> IIRC the
> reason for this design decision was that contexts in type signatures
> should always be explicit.
Got it ;) Thanks for prompt reply. What does "should always be explicit"
mean? Is there a notion of "explicit context" that
Hi all, I have an example wich I don't understand:
---begin
class C t
data T = T
instance C T
data C t => T1 t = T1
f1 :: T1 ()
f1 = T1
data C t => T2 t = T2 t
f2 :: T2 ()
f2 = T2 ()
end
The first function, f1, is accepted both by hugs and ghc, unlike the
second w
Alle 00:08, sabato 13 settembre 2003, [EMAIL PROTECTED] ha
scritto:
> ERROR "./mailalias.lhs":5 - Type error in final generator
> *** Term : map putStrLn strs
> *** Type : [IO ()]
> *** Does not match : IO a
>
> Can someone please explain what I'm doing wrong?
This is a type e
Inspired by the various replies to the "haskell for non-haskell sake" I
wonder why so much people uses haskell "only for prototipying" or
producing code in other languages.
I am just curios to hear from people who do not use haskell for project
releases, or just think it's not suitable for a ma
Alle 13:33, sabato 30 agosto 2003, Alastair Reid ha scritto:
> - Knit (http://www.cs.utah.edu/flux/knit/)
>
> A component language for C
Are there component languages wich work on multilanguage projects?
Something like "my project has a module written in haskell, one in C
and one in Ocaml, and
On Tue, 5 Aug 2003 15:30:44 +0200
Wolfgang Jeltsch <[EMAIL PROTECTED]> wrote:
>
> What negative consequences does their implementation have? I think,
> sometimes they could be quite handy.
That you have to solve a constraint system to compile your program,
AFAIK. But I guess that a brave GHC u
On Tue, 5 Aug 2003 15:23:09 +0200
Wolfgang Jeltsch <[EMAIL PROTECTED]> wrote:
>
> You could define different types for different natural numbers:
> data Zero = Zero
> data Succ number = Succ number
This resembles
http://www.brics.dk/RS/01/10/
V.
_
On Tue, 5 Aug 2003 12:23:06 +0200
Konrad Hinsen <[EMAIL PROTECTED]> wrote:
> 3
>
> Is there any way to parametrize a type by a value, rather than
> another type? What I would like to do is to define "list of length 3"
> and "list of length 4" as separate parametrization of the same type,
> su
On Mon, 4 Aug 2003 14:55:18 -0700
John Meacham <[EMAIL PROTECTED]> wrote:
>
> an MVar contains the current puff history, which s dumped to disk
> periodically if it has changed since the last dump, it relys on using
> DrIFT to derive a Binary instance for [Puff] and concurrency to spawn
> off
Is there someone who has implemented some limited form of persistency in
haskell? I don't mean the longly-debated persistence of functional
values, but something rough, like a persistent MVar with a thread saving
modified values every n seconds or so.
Vincenzo
_
Hi all, I am using "parsec" to parse the output from "xmame -listinfo"
wich is a list of records of the form
game (
attr1 value1
...
attrN valueN
)
and for approx. 3500 records I got ~250 mb of RSS memory during parsing,
wich takes 20 seconds on my athlon 1400.
I think that I must have
On Sat, 12 Jul 2003 07:47:02 -0700 (PDT)
Ron de Bruijn <[EMAIL PROTECTED]> wrote:
>
> It's ofcourse possible to put a list of Subjects that
> a Teacher teaches in the data declaration of the
> teacher. But then there is no way of saying
> efficiently (O(1) Just a pointer or index):"Give me a
On Wed, 26 Mar 2003 13:21:16 +0100
Nick Name <[EMAIL PROTECTED]> wrote:
> suspend :: ThreadID -> IO ()
^
Oh, yes, I meant
suspend :: ThreadID -> IO (IO ())
V.
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Hi all, is there a way, or is it planned to, or has anyone published
articles on... resuming from asynchronous exceptions?
I mean: it would be useful there was a
suspend :: ThreadID -> IO ()
where the result is the remaining computation of the other thread, wich
one could forkIO again, or simpl
I am trying to lazily wait an MVar in hugs, in conjunction with
concurrent haskell:
-
import Concurrent
import IOExts
f = do
v <- newEmptyMVar
c <- getContents
forkIO (putMVar v (head c))
r <- unsafeInterleaveIO (takeMVar v)
return v
f2 = f >>= unsafeInterleaveIO . takeM
On Mon, 10 Mar 2003 11:30:01 +
Alastair Reid <[EMAIL PROTECTED]> wrote:
> Nick name says that a problem with the first is:
> > The problem is that if no memory is allocated, no garbage collection
> > happens; of course finalization is not guaranteed, as the manual
>
As the result of a conversation on haskell-gui, I have tried to
implement the disallocation of resources when a stream is garbage
collected.
To explain myself:
I have a function
f :: IO [a]
which returns a lazy stream after allocating some resource to feed it
(say installing a callback).
I wis
On Fri, 7 Mar 2003 07:47:09 -0800 (PST)
Hal Daume III <[EMAIL PROTECTED]> wrote:
>
> That said, "undecidable instances" sound very scary, but they're
> really not. You can google around for a conversation I had with SPJ
> about this a while back, but something being an und instance is a
> co
Yes, I usually RTFM before posting, but you have misunderstood my
question (however, thanks for always reading and answering newbie
questions like mine); what I want to do is the
instance (Get a) => Functor a where
fmap f x = mk (ls x >>= return . map f)
Now, what I mean is: "any type in Ge
I want to declare the following:
class Get a where
ls :: a b -> IO [b]
mk :: IO [b] -> a b
instance (Get a) => Functor a where
fmap f x = mk (ls x >>= return . map f)
But to have ghc type everything, I have to turn on "-fglasgow-exts
-fallow-undecidable-instances -fallow-overlappin
On Sun, 2 Mar 2003 10:16:12 +0200
"Cagdas Ozgenc" <[EMAIL PROTECTED]> wrote:
> Could you give an intutive description of data construction
In some form of typed lambda-calculus, you have the sum and product
types. An example is PCF; see for example:
http://citeseer.nj.nec.com/howard90operational
On Fri, 31 Jan 2003 07:47:43 +
Glynn Clements <[EMAIL PROTECTED]> wrote:
> The usual fudge is:
>
> import IORef
> import IOExts
>
> globalVar :: IORef Int
> globalVar = unsafePerformIO $ newIORef 0
I see in the documentation of unsafePerformIO that no one make
On Tue, 28 Jan 2003 09:32:02 -
<[EMAIL PROTECTED]> wrote:
>
> Although this question is essentially personal in nature, I
> consider it to be
> (and tried to make it) broad enough to justify its presence here,
> propped up by Haskell being used around the world for teachi
On Thu, 23 Jan 2003 15:38:31 -0600
Jon Cast <[EMAIL PROTECTED]> wrote:
>
>
> > Another idea: if I allow the list of objects in the panel to be
> > infinite,
>
> Sorry, but I'm having difficulty figuring out where you'd get an
> infinite list of objects to put in the panel. I suspect any so
On Sun, 19 Jan 2003 16:02:41 -0600
Jon Cast <[EMAIL PROTECTED]> wrote:
> > But, to fully exploit the power of a "functionally-programmed"
> > desktop, the interface should allow the user to map an operation
> > onto all the objects of the panel; in this case the allowed
> > operations should be
On Tue, 21 Jan 2003 08:56:55 +0100
Martin Huschenbett <[EMAIL PROTECTED]> wrote:
> I just started some multithreaded programming and as I am
> a newbie, I've gat a question.
>
> 1.) What are the differences between IORefs and MVars?
Mvars ensure mutual exclusion, and they can be used as sinchron
On Sun, 19 Jan 2003 16:02:41 -0600
Jon Cast <[EMAIL PROTECTED]> wrote:
> So, I would attach a list of named operations of type (Dynamic ->
> Result) to each type, and offer the operations for a given type to
> the user.
Thanks for your answer, it's interesting.
What do you mean with "named ope
On Sun, 19 Jan 2003 12:50:16 -0600
Jon Cast <[EMAIL PROTECTED]> wrote:
> Short version: if
> Typeable is a super-class of Visible or mentioned in your existential
> type (i.e., forall a. (Visible a, Typeable a) => Con) you can use
> (fromDynamic . toDyn) to safely (attempt to) convert the abstr
Or maybe the subject has nothing to do with my question :)
I was thinking of an "haskell desktop interface", i.e. just a desktop
interface, but written in haskell.
I thought this: one can define a type class with the "view" method:
data Draw -- the drawing monad
class Visible t where
vi
On Thu, 5 Dec 2002 21:49:27 +0100
Ingo Wechsung <[EMAIL PROTECTED]> wrote:
>
> So I will write the braces and semicolons. It's better anyway in my
> opinion.
>
> I am not going to change my editing habits just to make hugs or ghc
> happy.
What about using untabified files? Or an haskell-a
On Wed, 4 Dec 2002 05:54:43 -0800 (PST)
Nuno Silva <[EMAIL PROTECTED]> wrote:
> descodificador = do c1 <- gera
> c2 <- gera
> c3 <- gera
> c4 <- gera
>
>"code in the
I have answered to this post but by mistake I was looking at the older
version of the report.
Vincenzo
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On Fri, 8 Nov 2002 10:35:33 +
Ross Paterson <[EMAIL PROTECTED]> wrote:
> The new copyright notice is inconsistent. If it is not otherwise
> changed, I suggest that the first clause, "The publisher intends this
> Report to belong to the entire Haskell community, ..." be deleted.
May I know wh
On 04 Nov 2002 12:16:01 +0100
Peter Simons <[EMAIL PROTECTED]> wrote:
> Unfortunately, the diagrams would have to be displayed and updated in
> real-time, sort of, because I'm writing a status monitor that will
> display useful information about your system, network, etc.
You can replot data e
On Sat, 12 Oct 2002 07:59:27 -0400
David Roundy <[EMAIL PROTECTED]> wrote:
> unsafeIO,
to lazily read a directory tree, I found the only way is to use
unsafeInterleaveIO, I hope someone corrects me.
This function is unsafe in the sense that IO is performed at a time
unrelated to the main IO tr
On 10 Oct 2002 10:29:24 +0200
[EMAIL PROTECTED] (Ketil Z. Malde) wrote:
> I realize it's probably far from trivial, e.g. comparing two equal
> numbers could easily not terminate,
you should compare into a given precision
V.
--
Fedeli alla linea, anche quando non c'è Quando l'imperatore è
mal
On Sat, 5 Oct 2002 18:41:06 -0400
David Roundy <[EMAIL PROTECTED]> wrote:
> How does one debug in haskell?
http://www.haskell.org/libraries/#tracing
Vincenzo
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On Thu, 26 Sep 2002 16:02:01 +0200 (MET DST)
Koen Claessen <[EMAIL PROTECTED]> wrote:
> In general, when using unsafePerformIO in this way, one
> wants to tell the compiler that it is not allowed to inline
> the expression. This can be done in most compilers by giving
> compiler pragma's.
In
I just wrote a long and clear answer, but my e-mail client has crashed.
I am going to change it (or to rewrite one in Haskell, grrr) but the
answer will be shorter, I apologize.
On Wed, 25 Sep 2002 16:34:02 -0700 (PDT)
Hal Daume III <[EMAIL PROTECTED]> wrote:
> I don't mean to troll, but this
On Wed, 25 Sep 2002 16:06:29 -0700 (PDT)
Hal Daume III <[EMAIL PROTECTED]> wrote:
> I don't feel bad about doing
> this because GHC does this itself for its own configuration :).
I am going to show you that using unsafePerformIO where there really are
side effects leads to unpredictable results
On Thu, 19 Sep 2002 21:28:31 +0100
Duncan Coutts <[EMAIL PROTECTED]> wrote:
>
> See unsafeInterleaveIO:
Thanks for help, I'm going to look at it.
Vincenzo
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How could I "zip" two possibily infinite streams obtained by IO
operations, for example to return the infinite list of pairs of values
read both from channel a and from channel b with getChanContents?
In general, how does one implement a function like "getChanContents"
wich returns an infinite l
On Sun, 28 Jul 2002 17:44:34 +0200
"Scott J." <[EMAIL PROTECTED]> wrote:
> I think I am in the wrong pub. It seems I am alone here.
?
Vincenzo
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Are we sure that Karen didn't mean "I don't care of unicode, just want
some example with ASCII code?"
In that case, well... Karen, what did you mean?
Vincenzo
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> Go to www.haskell.org, and look at Libraries and Tools. There you
> will see HOpenGL, which is just what you seek.
>
> http://haskell.org/HOpenGL/
I am sorry, I did not specify that I am already using HOpenGL and I am
subscribed to their ML. The matter is that there is no binding to a
truety
First, hi all. I am an haskeller newbie looking forward to conquer the
world with a functional language.
Part of this conquer involves IMHO writing a nice desktop, using modern
features of opengl, to make it portable. But, a question arises: all
opengl true type font renderers are written in C++,
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