On 18 Jul 2007, at 8:52 pm, Bjorn Bringert wrote:
Well, the original poster wanted advice on how to improve his
Haskell style, not algorithmic complexity. I think that the
appropriate response to that is to show different ways to write the
same program in idiomatic Haskell.
(a) I gave some
Miguel Mitrofanov, on 9 July [1]:
> I'm trying to do Exercise 2.5.2 from John Hughes's "Programming with
> Arrows". [...]
Sorry for the delayed reply. I've only just started learning about arrow
programming, and since no-one else has replied to you, here is what I've
discovered so far...
I think
On 7/18/07, Michael Vanier <[EMAIL PROTECTED]> wrote:
We always say that Haskell is named for Haskell Curry because his work provided
the
logical/computational foundations for the language. How exactly is this the
case? Specifically,
does anyone claim that Curry's combinatorial logic is more
Hi Claus
Ising ghc-6.6 and Opera 9.20 i thought that everything would work until
I tried the page in Firefox 2.0.0.1
Opera:
Those maroon rectangles in all four corners appear, alse the text
x/y: ... is shown when clicking.
But the drawing doesn't appear, does'n show any errors within the Error
Co
We always say that Haskell is named for Haskell Curry because his work provided the
logical/computational foundations for the language. How exactly is this the case? Specifically,
does anyone claim that Curry's combinatorial logic is more relevant to the theoretical foundations
of Haskell than
On Thu, 2007-07-19 at 00:12 +0100, Claus Reinke wrote:
> gui libs are wonderful, but haskell sometimes has too few
> and sometimes has too many. and those we have do not
> work with every haskell implementation. and when they do
> work (usually with ghc, these days), they need to be rebuilt
> whe
gui libs are wonderful, but haskell sometimes has too few
and sometimes has too many. and those we have do not
work with every haskell implementation. and when they do
work (usually with ghc, these days), they need to be rebuilt
whenever ghc is updated, even if the gui lib hasn't changed
at all
On 18/07/07, J. Garrett Morris <[EMAIL PROTECTED]> wrote:
You're partway there - concatMap is flip (>>=), so you have the xs >>=
(\x -> ) part.
Ah, yes! I read about this equivalence in one of the other threads
today but it didn't make any connection. Doh!
I think I will have to, sooner or la
On 23:25 Wed 18 Jul , Andreas Marth wrote:
> Thanks for again pointing out that I didn't want another way to get the
> information, but I have to defend Simon.
> [...]
> 1) make the wiki search function return all documents containig the search
> term (who can do that?)
> 2) consider creating a
On Wed, 2007-07-18 at 14:06 -0500, Antoine Latter wrote:
> MediaWiki's search isn't fantastic - what I did was a google search on
> "site:www.haskell.org DLL"
>
> It's not a very good answer, but it's the only answer I know.
>
In general I find Google's search to be more comprehensive and effect
On Wednesday 18 July 2007 21:16, Johan Tibell wrote:
> It would be nice if it was possible to capture this kind of behavior in a
> high order function just like map though. I guess the problem is that the
> function to map will take different number of arguments depending on the
> use case.
>
> loo
Thanks for again pointing out that I didn't want another way to get the
information, but I have to defend Simon.
His first response was a reworking of the wiki page for the haskell mailing
lists.
What led me to learning about gmain and its search function.
So I added the hint that you can use gmain
Hi,
Am Mittwoch, den 18.07.2007, 13:42 -0700 schrieb Alexteslin:
> I am trying to define a function as part of the exercises that gives a
> result of a minimum value of the input list of ints. Such as this:
>
> minimumValue :: [Int] -> Int
> minimumValue ns ...
>
> using either filter or map fun
On 18/07/07, Alexteslin <[EMAIL PROTECTED]> wrote:
Hello,
I am trying to define a function as part of the exercises that gives a
result of a minimum value of the input list of ints. Such as this:
minimumValue :: [Int] -> Int
minimumValue ns ...
using either filter or map functions but Not fol
Bryan Burgers wrote:
I heard that Fermat didn't even actually have a proof.
That's unsubstantiated conjecture! :-P
Oh, sure, it took over 300 years to arrive at the modern-day proof,
which runs to over 400 pages of cutting-edge mathematics spanning
multiple very modern disiplins, and is so d
On 7/18/07, Dougal Stanton <[EMAIL PROTECTED]> wrote:
I worked out that [ (a,b) | a <- as, b <- bs ] must be equivalent to
> comp = concatMap (\x -> map ((,) x) ys) xs
but I can't really say how conditions like "a /= b" get slotted in to
that style. Is there a reference for that?
As I underst
Hello,
I am trying to define a function as part of the exercises that gives a
result of a minimum value of the input list of ints. Such as this:
minimumValue :: [Int] -> Int
minimumValue ns ...
using either filter or map functions but Not foldr1, because the exercise
precedes the section on fol
On Wed, 18 Jul 2007 13:00:20 -0700, you wrote:
>You can even post via gmane.
>
>Tip: for more powerful searching, use Thunderbird + gmane's NNTP interface.
I think people are missing the original poster's point. He's not looking
for alternative ways to get from A to B; he's pointing out that a
ty
On 18/07/07, apfelmus <[EMAIL PROTECTED]> wrote:
I like it for its elegant point-free style :)
Yes, well, I am rather enamoured of them! :-)
Apparently, difference can only detect character replacements but not
character insertion or deletion, but that's probably not your use case.
Yes, th
You can even post via gmane.
Tip: for more powerful searching, use Thunderbird + gmane's NNTP interface.
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
Hi,
Ii is interesting that in ML, the presence of mutable ref cells and
parametric polymorphism requires the whole language to be dominated by a
"value restriction" [1] to ensure that the type system remains sound,
whereas in Haskell, because IORef's can only be created (and used) in
the IO mo
Now I learned that gmain has a niche interface that can search the mailing
list & sort the results. :-)
I changed the (read via gmain) into (read & search via gmain) for both links
at that page.
So one easily can see that he can search the archives via gmain. (I didn't
know gmain at all, so had no
Hi Andreas - very good problem report, thanks.
I have just cleaned up the archive links at
http://www.haskell.org/haskellwiki/Mailing_lists a bit. I added the
ever-excellent gmane and an overview of all archives. I think some of the
archive descriptive text is no longer needed, but I stopped h
MediaWiki's search isn't fantastic - what I did was a google search on
"site:www.haskell.org DLL"
It's not a very good answer, but it's the only answer I know.
On 7/18/07, Andreas Marth <[EMAIL PROTECTED]> wrote:
- Original Message -
From: "Antoine Latter" <[EMAIL PROTECTED]>
To:
Sent
Hello Andreas,
Wednesday, July 18, 2007, 10:36:14 PM, you wrote:
> I am not sure what you are refering to.
i will go into Special pages -> All pages
and not seeing any "dll" here, will go to ask in haskell-cafe/irc
--
Best regards,
Bulatmailto:[EMAIL PROTECTED]
__
- Original Message -
From: "Antoine Latter" <[EMAIL PROTECTED]>
To:
Sent: Wednesday, July 18, 2007 8:26 PM
Subject: Re: [Haskell-cafe] Frustrating experience of a wannabe contributor
> The closest existing page I could find on the wiki was this one:
>
> http://www.haskell.org/haskellwik
I am not sure what you are refering to.
Are there any pages about DLLs that I didn't find? If so why couldn't I find
them?
Are you refering to wiki pages in general? I never said that there are no
wiki pages.
I just said that I couldn't find an appropriate place where I would post
something about c
The closest existing page I could find on the wiki was this one:
http://www.haskell.org/haskellwiki/GHC/Using_the_FFI
But it is a Wiki. If you were to just make a page and put it
somewhere, I doubt anyone would get too mad.
On 7/18/07, Bulat Ziganshin <[EMAIL PROTECTED]> wrote:
Hello Andreas,
Hello Andreas,
Wednesday, July 18, 2007, 8:17:38 PM, you wrote:
> So I tried to find a place where it might have posted or at least fit into.
there is a full list of wiki pages
--
Best regards,
Bulatmailto:[EMAIL PROTECTED]
This is probably just me, but I've always mentally separated the list
monad (representing choice) from operations on ordered sets
implemented by lists (which don't always have to represent choice).
In this case, since the remainder of the code wasn't monadic, I find
it much easier to understand wh
> Btw, if you don't want the empty lists, you can use
>
> concatMap (init . tails) . tail . inits
Would it not be more efficient and perspicuous to keep the sublists
definition as is, just interchanging inits and tails?
where sublists = filter (not . null) . concatMap tails . inits
Or a
Today I had 2 hours time and thought I might contribute to the haskell
community.
The topic I thought I might be able to give some hints is about creating
DLLs.
So I went to www.haskell.org which redirected me to the wiki
www.haskell.org/haskellwiki/Haskell.
So I entered "DLL" into the search to fi
Dougal Stanton wrote:
> The following is a slap-dash program for generating a list of pairs of
> words which differ by, at most, one letter. It's quite verbose at the
> moment, because (a) that was the way I wrote it, a snippet at a time,
> and (b) I lack the wit to make it shorter.
>
> Can anyone
Hi Dmitri,
I built gtk2hs on Windows with GHC 6.6.1 and gtk2hs-0.9.11. Here's are the
steps that worked for me: (not sure I didn't missed some)
First you need to install a GTK+ development package for windows. I think
mine comes from http://gladewin32.sourceforge.net/modules/wfdownloads/
Then y
Andy Oram over at O'Reilly just posted an article analyzing how
mailing list readers are helped or hindered in the Perl and Ruby on
Rails communities. His most interesting conclusion is that many
posters come without the background needed to understand answers. That
is certainly been the case on t
On Wednesday 18 July 2007, Johan Tibell wrote:
> It would be nice if it was possible to capture this kind of behavior in a
> high order function just like map though. I guess the problem is that the
> function to map will take different number of arguments depending on the
> use case.
>
> lookAtTwo
J. Garrett Morris wrote:
>-- the tails function returns each tail of the given list; the
> inits function
>-- is similar. By mapping inits over tails, we get all the sublists.
>where sublists = filter (not . null) . concatMap inits . tails
Nice, but
concatMap tails . inits
is mu
Sounds like what I want. I'll give it a try. Thanks.
On 7/18/07, Tillmann Rendel <[EMAIL PROTECTED]> wrote:
Johan Tibell wrote:
> I found myself wanting a map that looks at neighboring elements. This is
> where I used explicit recursion the most. Something like this:
>
> f [] = []
> f ((Foo a)
Johan Tibell wrote:
I found myself wanting a map that looks at neighboring elements. This is
where I used explicit recursion the most. Something like this:
f [] = []
f ((Foo a) : (Bar b) : xs)
| fooBar a b = Foo a : f xs
| otherwise = Bar b : f xs
This is almost a map. A variation is when f
On 7/18/07, Martin Coxall <[EMAIL PROTECTED]> wrote:
On 7/18/07, Jon Harrop <[EMAIL PROTECTED]> wrote:
> On Tuesday 17 July 2007 23:26:08 Hugh Perkins wrote:
> > Am I the only person who finds it interesting/worrying that there are few
> > to no people in the group who are ex-C# programmers. I m
On 7/17/07, Malte Milatz <[EMAIL PROTECTED]> wrote:
Dmitri O.Kondratiev:
> It looks like Graphics.SOE does not anymore exist in GHC 6.6.1.
> Where one can get it or what to use instead of it?
You may try Gtk2Hs, which includes an implementation of SOE, called
Graphics.SOE.Gtk. (It works ind
On 18-jul-2007, at 14:09, Marc Weber wrote:
On Tue, Jul 17, 2007 at 03:27:20PM -0700, brad clawsie wrote:
On Wed, Jul 18, 2007 at 12:17:12AM +0200, Hugh Perkins wrote:
On 7/17/07, Martin Coxall <[EMAIL PROTECTED]> wrote:
I wonder why 'we' aren't pushing things like this big time. When
Rub
Arie Groeneveld wrote:
Ok, so when do I use nub instead of 'map head.group.sort'?
Never. If |nub_sort=map head.group.sort| is applicable, then you are
dealing with a member of class Ord, so use the O(n*log n) |nub_sort|. If
you want to preserve the relative order of the input list, use somet
Arie Groeneveld wrote:
Hi,
Wondering about time space consuming: 'nub' vs 'map head.group.sort'
Consider:
ry = [1..1] ++ replicate 13 5 ++ replicate 21 34
*Main> length . nub $ ry
1
(5.18 secs, 105 bytes)
*Main> length . map head . group . sort $ ry
1
(0.03 secs, 6293384 b
On 7/18/07, Arie Groeneveld <[EMAIL PROTECTED]> wrote:
Ok, so when do I use nub instead of 'map head.group.sort' ?
Using nub gave me a lot of trouble in terms of time consumption
while handling long lists.
Well, nub is non-strict, so you can use it on infinite or partial
lists, provided you do
I think that it's simply a buildfile error, that requires X11 even if
you are on windows.
The problem is that the building process requires running a configure
script, so it requires a cygwin environment under windows.
If you need HGL only for "educational" purposes, I strongly suggest
you to dow
On Wed, Jul 18, 2007 at 03:58:58PM +0400, Dmitri O.Kondratiev wrote:
> Andrea thanks!
> I tried to install HGL on Win32 and got this unresolved dependency:
>
> HGL-3.1>runghc Setup.hs configure
> Configuring HGL-3.1...
> configure: Dependency base-any: using base-2.1.1
> Setup.hs: cannot sat
Arie,
Ok, so when do I use nub instead of 'map head.group.sort' ?
Well, for one thing, |map head . group . sort| produces a sorted
list, wheras |nub| preserves the order of the input list.
Cheers,
Stefan
___
Haskell-Cafe mailing list
Haskell-C
Miguel Mitrofanov wrote:
> AG> Wondering about time space consuming: 'nub' vs 'map
> AG> head.group.sort'
>
> Prelude> :t Data.List.nub
> Data.List.nub :: (Eq a) => [a] -> [a]
> Prelude> :t Data.List.sort
> Data.List.sort :: (Ord a) => [a] -> [a]
>
> nub uses less information than sort, so it MUST
AG> Wondering about time space consuming: 'nub' vs 'map
AG> head.group.sort'
Prelude> :t Data.List.nub
Data.List.nub :: (Eq a) => [a] -> [a]
Prelude> :t Data.List.sort
Data.List.sort :: (Ord a) => [a] -> [a]
nub uses less information than sort, so it MUST be slower.
_
DFP> Yes, but that generality is entirely wasted here and thus an
DFP> obscuring element. There is no way that this function can be
DFP> generalized to work with other monads.
As for me, concatMap (and concat.map as well) seems much more
obscuring. (>>=) is so general, that I use it almost everywh
On Tue, Jul 17, 2007 at 03:27:20PM -0700, brad clawsie wrote:
> On Wed, Jul 18, 2007 at 12:17:12AM +0200, Hugh Perkins wrote:
> > On 7/17/07, Martin Coxall <[EMAIL PROTECTED]> wrote:
> >>
> >> I wonder why 'we' aren't pushing things like this big time. When Ruby
> >> took off, more than anything e
*Andrea Rossato* wrote:
Hi!
as far as I know what you are looking for (Graphics.SOE) is part of
HGL. Have a look here:
http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HGL-3.1
Hope I got it right and that this helps.
All the best,
Andrea
Andrea thanks!
I tried to install HGL on Wi
On Jul 17, 2007, at 10:13 PM, Tony Morris wrote:
David F. Place wrote:
The use of >>= is just an obscure way of saying (flip concatMap).
Correction.
The use of >>= is a more general way of saying (flip concatMap).
Tony Morris
Yes, but that generality is entirely wasted here and thus an
Hi,
Wondering about time space consuming: 'nub' vs 'map head.group.sort'
Consider:
ry = [1..1] ++ replicate 13 5 ++ replicate 21 34
*Main> length . nub $ ry
1
(5.18 secs, 105 bytes)
*Main> length . map head . group . sort $ ry
1
(0.03 secs, 6293384 bytes)
Time sp
On Tue, Jul 17, 2007 at 06:52:43PM +0400, Dmitri O.Kondratiev wrote:
> I am trying to use Graphics.SOE (that was present at least in GHC 6.4) to
> go through "Simple Graphics" examples as described in Pail Hudak book "The
> Haskell School of Expression. Learning functional programming through
>
It would be nice if it was possible to capture this kind of behavior in a
high order function just like map though. I guess the problem is that the
function to map will take different number of arguments depending on the use
case.
lookAtTwo a b = ...
lookAtThree a b c = ...
map' :: (a -> ... ->
Dave Bayer wrote:
> Here is a prime sieve that can hang within a factor of two of the fastest
> code in that thread, until it blows up on garbage collection:
>
> -
>
> diff :: Ord a => [a] -> [a] -> [a]
> diff xs@(x:xt) ys@(y:yt) = c
On Jul 18, 2007, at 2:13 , ok wrote:
On Jul 17, 2007, at 22:26 , James Hunt wrote:
As a struggling newbie, I've started to try various exercises in
order to improve. I decided to try the latest Ruby Quiz (http://
www.rubyquiz.com/quiz131.html) in Haskell.
Haskell guru level: I am comforta
Johan Tibell wrote:
> I found myself wanting a map that looks at neighboring elements. This is
> where I used explicit recursion the most. Something like this:
>
> f [] = []
> f ((Foo a) : (Bar b) : xs)
> | fooBar a b = Foo a : f xs
> | otherwise = Bar b : f xs
>
> This is almost a map. A var
I found myself wanting a map that looks at neighboring elements. This is
where I used explicit recursion the most. Something like this:
f [] = []
f ((Foo a) : (Bar b) : xs)
| fooBar a b = Foo a : f xs
| otherwise = Bar b : f xs
This is almost a map. A variation is when filtering and you want
On 7/18/07, Jon Harrop <[EMAIL PROTECTED]> wrote:
On Tuesday 17 July 2007 23:26:08 Hugh Perkins wrote:
> Am I the only person who finds it interesting/worrying that there are few
> to no people in the group who are ex-C# programmers. I mean, you could
> argue that C# programmers are simply too s
On 7/17/07, Thomas Conway <[EMAIL PROTECTED]> wrote:
On 7/18/07, Hugh Perkins <[EMAIL PROTECTED]> wrote:
> Am I the only person who finds it interesting/worrying that there are few to
> no people in the group who are ex-C# programmers. I mean, you could argue
> that C# programmers are simply too
63 matches
Mail list logo
