2009/9/15 Matthias Kilian :
> A fellow openbsd developer told me the URL below...
>
> I hope this hasn't been posted on this list already (at least I
> didn't find it in my local archives):
>
> http://tommd.wordpress.com/2009/09/13/kernel-modules-in-haskell/
I don't think it was posted here, but i
Dear all,
Here is a note concerning a thought I just had. I have written a rough
sketch/outline and
would like feedback upon this.
The beginning thought: I would like to be able to write new
bracket-like operators
without having to rewrite GHC. (Case in point: applicative brackets.)
First idea i
On Fri, Sep 11, 2009 at 5:55 PM, Jeremy O'Donoghue <
jeremy.odonog...@gmail.com> wrote:
>
>
> I don't have anything as neat to show you as Duncan's suggetion (I'd also
> be interested to see a cleaner way to do it - this sort of code always
> grates a little with me, although all of the major Has
On Mon, Sep 14, 2009 at 10:25 AM, Martijn van Steenbergen
wrote:
> Hello cafe,
>
> Inspired by Sean Leather's xformat package [1] I built a datatype with which
> you can build a monoid with holes, yielding a function type to fill in these
> holes, continuation-passing style. Here are some primitiv
On Mon, Sep 14, 2009 at 11:25 AM, Martijn van Steenbergen
wrote:
> Inspired by Sean Leather's xformat package [1] I built a datatype with which
> you can build a monoid with holes, yielding a function type to fill in these
> holes, continuation-passing style.
Neat!
> I have a couple of questions
You might want to take a look at
RFC 2445
Internet Calendaring and Scheduling Core Object Specification
Section 4.8.5.4 Recurrence Rule
--
Iain Alexander i...@stryx.demon.co.uk
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haske
Hello,
I'm having some trouble correctly linking to externally generated
object code when using ghci. I'm loading a Cabal package Foo, that
has already been successfully installed:
>ghci -package Foo
ghc-6.8.3:
unknown symbol `_iceExePath'
Loading package Foo-0.1 ... linking ... ghc-6.8.3:
On Tue, Sep 15, 2009 at 10:14 AM, Manuel Simoni wrote:
> Hello!
>
> I'm trying to wrap my head around OO'Haskell's notion of objects as fixpoints.
>
> Is OO'Haskell's use of mfix simply a use of something like a monadic
> Y-combinator to give the object access to its own "identity"?
More or less,
> But pedantically even the function:
>
>> quux :: Int -> Int
>> quux x = trace "Quux" (bar 12)
>
>> optmain :: IO ()
>> optmain = quux 10 `seq` quux 11 `seq` return ()
>
> might print only once if GHC at the optimization level selected recognizes
> that quux doesn't depend on its argument and rewr
Am Dienstag 15 September 2009 23:13:59 schrieb Cristiano Paris:
> On Wed, Sep 2, 2009 at 7:16 AM, zaxis wrote:
> > Isnot it clear without the 'forall' ?
> > data Branch tok st a = Branch (PermParser tok st (b -> a)) (GenParser tok
> > st b)
> >
> > thanks!
>
> I elaborated on this and I wish to ad
On Tue, Sep 15, 2009 at 8:48 AM, Andrew Coppin
wrote:
> Using explicit threads has the nice side-effect...
side-effects are bad! ;-)
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
Am Dienstag 15 September 2009 23:00:40 schrieb Cristiano Paris:
> On Tue, Sep 15, 2009 at 10:42 PM, Daniel Fischer
>
> wrote:
> >
> > Aaawww.
> > let b' = length b
> > or
> > let b' = foldl' seq () b
> > or
> > let b' = b `using` rnf
> >
> > if you want to force the whole file to be read. But
On Wed, Sep 2, 2009 at 7:16 AM, zaxis wrote:
>
> Isnot it clear without the 'forall' ?
> data Branch tok st a = Branch (PermParser tok st (b -> a)) (GenParser tok st
> b)
>
> thanks!
I elaborated on this and I wish to add my personal way of figuring out
what the "forall" keyword means.
When you
On Mon, Sep 14, 2009 at 11:32:04PM -0400, John Van Enk wrote:
> http://hackage.haskell.org/package/EnumMap
>
> Changes pushed. Job Vranish added the SPECIALIZE pragmas, and I believe he
> has more data concerning how much this helps.
Thanks a lot! :)
--
Felipe.
___
On Tue, Sep 15, 2009 at 10:42 PM, Daniel Fischer
wrote:
>
> Aaawww.
> let b' = length b
> or
> let b' = foldl' seq () b
> or
> let b' = b `using` rnf
>
> if you want to force the whole file to be read. But then you should
> definitely be using
> ByteStrings.
Yep. But that doesn't solve the
Am Dienstag 15 September 2009 22:25:31 schrieb Cristiano Paris:
> On Tue, Sep 15, 2009 at 10:11 PM, Cristiano Paris wrote:
> > On Tue, Sep 15, 2009 at 10:08 PM, Cristiano Paris
> > wrote:
> >> ...
> >> So, it seems that "seq b" is completely ineffective and program is not
> >> correct.
> >
> > C
On Tue, Sep 15, 2009 at 10:29 PM, Daniel Fischer
wrote:
> ...
> It evaluates the String far enough to know whether it's "" or (_:_), that is,
> to weak head
> normal form. It doesn't look at any character, but it forces at least one
> character to be
> read from the file.
Yep, the head. That ex
A fellow openbsd developer told me the URL below...
I hope this hasn't been posted on this list already (at least I
didn't find it in my local archives):
http://tommd.wordpress.com/2009/09/13/kernel-modules-in-haskell/
Ciao,
Kili
--
Logging should be in debug mode only. If every netw
On Tue, Sep 15, 2009 at 10:08 PM, Cristiano Paris wrote:
> ...
> So, it seems that "seq b" is completely ineffective and program is not
> correct.
Correction: removing "seq b" results in nothing being displayed :)
So, it's not "completely" effective. I suspect this is related to the
fact that a
On Tue, Sep 15, 2009 at 9:29 PM, Daniel Fischer
wrote:
> Am Dienstag 15 September 2009 21:13:02 schrieb Daniel Fischer:
>> Still, the body should be read lazily.
>> I'm not sure, but the tracing message may be output because of its
>> position.
>>
>> With
>>
>> where
>> readBody = withFile fn
Am Dienstag 15 September 2009 22:17:00 schrieb Cristiano Paris:
> On Tue, Sep 15, 2009 at 10:12 PM, Ross Mellgren wrote:
> > Wouldn't seq b only force (at minimum) the first character of the file?
>
> I think it force the evaluation of the "Cons" in the String but not
> the characters therein.
It
On Tue, Sep 15, 2009 at 10:25 PM, Cristiano Paris wrote:
> ...
> Two points:
>
> 1 - I had to cut off file1.txt to be just above 1024 bytes otherwise
> the program becomes extremely slow even on a 100KB file with a line
> being output every 5 seconds and with my CPU being completely busy
> (I'm us
On Tue, Sep 15, 2009 at 10:20 PM, Ross Mellgren wrote:
> Ack, IGNORE ME! Way too strict.
Oh, well, I used foldr+seq to achieve the same result... I think, but
I think that, if this is the solution, I'll use rnf as I did on other
occasions.
Thanks.
Cristiano
_
On Tue, Sep 15, 2009 at 10:11 PM, Cristiano Paris wrote:
> On Tue, Sep 15, 2009 at 10:08 PM, Cristiano Paris wrote:
>> ...
>> So, it seems that "seq b" is completely ineffective and program is not
>> correct.
>
> Correction: removing "seq b" results in nothing being displayed :)
>
> So, it's not
Block, line or 'beam' decomposition tends to work well for raytracing tasks,
because they tend to give you a good cache locality and don't create a
ridiculous explosion of parallel jobs.
You'll need to do some tuning to figure out the right granularity for the
decomposition. But typically a few hu
Ack, IGNORE ME! Way too strict.
-Ross
On Sep 15, 2009, at 4:20 PM, Ross Mellgren wrote:
Ah yeah, that too. Control.Parallel.Strategies.rnf to the rescue?
-Ross
On Sep 15, 2009, at 4:17 PM, Cristiano Paris wrote:
On Tue, Sep 15, 2009 at 10:12 PM, Ross Mellgren hask...@z.odi.ac> wrote:
Wouldn
Ah yeah, that too. Control.Parallel.Strategies.rnf to the rescue?
-Ross
On Sep 15, 2009, at 4:17 PM, Cristiano Paris wrote:
On Tue, Sep 15, 2009 at 10:12 PM, Ross Mellgren hask...@z.odi.ac> wrote:
Wouldn't seq b only force (at minimum) the first character of the
file?
I think it force the e
On Tue, Sep 15, 2009 at 10:12 PM, Ross Mellgren wrote:
> Wouldn't seq b only force (at minimum) the first character of the file?
I think it force the evaluation of the "Cons" in the String but not
the characters therein.
Cristiano
___
Haskell-Cafe mail
Wouldn't seq b only force (at minimum) the first character of the file?
-Ross
On Sep 15, 2009, at 4:08 PM, Cristiano Paris wrote:
On Tue, Sep 15, 2009 at 9:29 PM, Daniel Fischer
wrote:
Am Dienstag 15 September 2009 21:13:02 schrieb Daniel Fischer:
Still, the body should be read lazily.
I'm
I agree with what you meant, but not quite with what you said. To be
pedantic:
> import Debug.Trace
> foo :: Int
> foo = trace "Foo" (bar 12)
> bar :: Int -> Int
> bar x = trace "Bar" x
> main :: IO ()
> main = foo `seq` foo `seq` return ()
main prints "Foo\nBar\n" showing that the bar is only
On Tue, Sep 15, 2009 at 9:39 PM, Svein Ove Aas wrote:
> As a general sort of warning, do not use hGetContents (or lazy i/o, in
> general) in combination with withFile.
>
> withFile closes the handle when the program lexically exits its scope.
> However, when using hGetContents, the file contents w
As a general sort of warning, do not use hGetContents (or lazy i/o, in
general) in combination with withFile.
withFile closes the handle when the program lexically exits its scope.
However, when using hGetContents, the file contents will not be read
until after you do this, and will therefore fail
On Tue, Sep 15, 2009 at 9:16 PM, Svein Ove Aas wrote:
> I have a number of suggestions, some of which conflict with each
> other, so I'll just throw them out here. Let's see..
:)
> First off, the IO monad does indeed enforce sequencing; that's its
> primary purpose.
So, unsafePerformIO can be t
Am Dienstag 15 September 2009 21:13:02 schrieb Daniel Fischer:
> Still, the body should be read lazily.
> I'm not sure, but the tracing message may be output because of its
> position.
>
> With
>
> where
> readBody = withFile fn ReadMode $ \h -> do
> b <- hGetContents h
> seq b
On Tue, Sep 15, 2009 at 9:13 PM, Daniel Fischer
wrote:
> ...
> Still, the body should be read lazily.
> I'm not sure, but the tracing message may be output because of its position.
>
> With
>
> where
> readBody = withFile fn ReadMode $ \h -> do
> b <- hGetContents h
> seq b $ retu
I have a number of suggestions, some of which conflict with each
other, so I'll just throw them out here. Let's see..
First off, the IO monad does indeed enforce sequencing; that's its
primary purpose. However, you can ask for it to run I/O out of order,
specifically when the value the out-of-orde
Am Dienstag 15 September 2009 20:36:06 schrieb Cristiano Paris:
> Hi Cafè,
>
> I've the following problem: I have a (possibly very long) list of
> files on disk. Each file contains some metadata at the beginning and
> continues with a (possibly very large) chunk of data.
>
> Now, the program I'm wr
Hi Cafè,
I've the following problem: I have a (possibly very long) list of
files on disk. Each file contains some metadata at the beginning and
continues with a (possibly very large) chunk of data.
Now, the program I'm writing can be run in two modes: either read a
specific file from the disk and
Thanks for explanation Sean!
On Tue, Sep 15, 2009 at 4:30 PM, Sean Leather wrote:
>
>
>> "Existential types" sounds a bit scary :)
>>
>>>
> It's unfortunate that they've developed a scariness feeling associated with
> them. They can be used in strange ways, but simple uses are quite
> approachab
> I'm trying to wrap my head around OO'Haskell's notion of objects as
> fixpoints.
>
> Is OO'Haskell's use of mfix simply a use of something like a monadic
> Y-combinator to give the object access to its own "identity"?
>
I don't remember the details exactly, but isn't it to support open recursion
> "Existential types" sounds a bit scary :)
>
>>
It's unfortunate that they've developed a scariness feeling associated with
them. They can be used in strange ways, but simple uses are quite
approachable. One way to think of them is like implementing an
object-oriented interface. You know it's an o
Hello!
I'm trying to wrap my head around OO'Haskell's notion of objects as fixpoints.
Is OO'Haskell's use of mfix simply a use of something like a monadic
Y-combinator to give the object access to its own "identity"?
Thanks,
Manuel
___
Haskell-Cafe mai
It's hard to say what really is 2d or 3d. Think about closed 3d curve
(points placed in 3d space somehow). Is it 2d or 3d? Depends on the
interpretation.
Usually DCC packages don't care about this. And I wouldn't too :p Who needs
extra level of complexity without any reason?
On Tue, Sep 15, 2009 a
I think you are in trouble because you have mixed 2D and 3D shapes in
one data type.
--not checked for typos, syntax, idiocy etc.
{-# LANGUAGE GADTs #-}
data Z
data S n
type Two = S (S Z)
type Three = S Two
data Geometry dims where
Sphere :: Position -> Radius -> Geometry Three
Cylinder
Cool. It's more and more clear guys.
Thanks a lot. I'll check that "expression problem".
"Existential types" sounds a bit scary :)
On Tue, Sep 15, 2009 at 3:26 PM, Sean Leather wrote:
>
>
>> Perimeter doesn't make sense for Sphere or Cylinder. So we could define a
>> type class for objects that
> Perimeter doesn't make sense for Sphere or Cylinder. So we could define a
> type class for objects that have perimeter and make an instance of it only
> for Circle (data Circle = Circle Position Radius). Make sense. But these
> three functions above have desired behaviour. If user has a list of o
> perimeter :: Geometry -> Double
> perimeter (Sphere _ r) = 0.0
> perimeter (Circle _ r) = 2.0 * pi * r
>
> The latter is even simpler because there is no need in extraction of Double
> value from Maybe.
I'd strongly advise against this last one on style grounds. (0 :: Double)
isn't nearly as s
-- Forwarded message --
From: Lyndon Maydwell
Date: Tue, Sep 15, 2009 at 10:03 PM
Subject: Re: [Haskell-cafe] Typeclasses vs simple functions?
To: Olex P
I think it depends on what is going to be using the functions, data.
As far as I can tell, type classes seem to be used in co
Well... How this:
instance Encircled Geometry where
perimeter (Sphere _ r) = Nothing
perimeter (Circle _ r) = Just $ 2.0 * pi * r
differs from this:
perimeter :: Geometry -> Maybe Double
perimeter (Sphere _ r) = Nothing
perimeter (Circle _ r) = Just $ 2.0 * pi * r
and from this:
Now it's at version 0.1.2 with the EnableGUI fix for Mac OS X.
On 9/14/09, Paul L wrote:
> I just bumped the version to 0.1.1 that fixes an embarrassing bug,
> i.e., the first example shown on the screen was actually wrong.
>
> I took a screenshot of the interaction net showing (church 2) f x,
>
Hello Thiago, John.
I've taken the Oracle HDBC driver at
http://thiagoarrais.com/repos/hdbc-oracle
modified it just a little to suite 6.10.4 and briefly looked if it works.
It does, that's cool! Thanks Thiago!
A question follows, maybe it's worth to mention it at the HDBC page
and/or put it
Yes, I'm aware of that, but not the details, so thanks for the info.
Anyway, I quickly tested Regis's idea in C#, and it works as he said.
http://hpaste.org/fastcgi/hpaste.fcgi/view?id=9392#a9392
- When trying to create a folder in ProgramFiles, you get an access
denied exception, unless the prog
Hi Andrew,
2009/9/15 Andrew Coppin :
> ...
> I'm presuming that sparking every individual point is going to create
> billions of absolutely tiny sparks, which probably won't give great
> performance. We could spark every line rather than every point?
> ...
You should just try: no one can say if p
I have a number of compute-bound graphics programs written in Haskell.
(Fractal generators, ray tracers, that kind of thing.) GHC offers
several concurrency and parallelism abstractions, but what's the best
way to use these to get images rendered as fast as possible, using the
available compute
Sure! I completely forgot about Maybe. The only one question is is it good
from the point of view of ordinary user who doesn't know about such things
like functional programming, monads etc. Imagine average user who is looking
into a spreadsheet and sees values 0.1, 1.4, Nothing... From other side
Hey guys,
It's a dumb question but I'd like to know a right answer...
Let's say we have some geometry data that can be Sphere, Cylinder, Circle
and so on. We can implement it as new data type plus a bunch of functions
that work on this data:
data Geometry = Sphere Position Radius
Hello Peter,
Tuesday, September 15, 2009, 1:24:26 PM, you wrote:
in order to protect from viruses and so now windows programs should be
split into two parts - one that doesn't need admin privileges and one
that needs them. as far as your actions doesn't need second part, you
are running first pro
It is possible for an executable with less privileges to
"shellexecute" an executable that requires admin rights? Won't this
immediately raise an "access denied" or other security exception
again? Don't know, it might be possible, but it's worth to check it
out before going this route (which is rat
> > - use windows API for requesting elevation during the process (ugly)
>
> If it really has to be done, then this seems like the best approach. In
> principle there's no problem with calling funky win32 functions in
> Cabal, it's mostly a matter of working out what bahaviour we want and
> what
59 matches
Mail list logo
