Interesting. Can you make the definition of quicksort non-recursive,
too? Perhaps with help of a bootstrapping combinator like the one
implicit in the approach I have given earlier?
treeSort = bootstrap partitionOnMedian
bootstrap f = Fix . helper . f
where helper = fmap (Fix . helper .
Matthias Görgens wrote:
Interesting. Can you make the definition of quicksort non-recursive,
too? Perhaps with help of a bootstrapping combinator like the one
implicit in the approach I have given earlier?
treeSort = bootstrap partitionOnMedian
bootstrap f = Fix . helper . f
where
Excerpts from Jeff Wheeler's message of Thu Jul 09 00:27:51 +0200 2009:
I'm excited to announce the first version of hsparql. HSparql makes it
easy to query SPARQL-compliant servers using a relatively intuitive DSL
and very simple client.
I've looked at your DSL and it looks really neat. While
Thanks. I heard about the hylo-, ana- and catamorphisms before, but
never explicitly used them. Time to get started.
And yet another question: One can get the median in deterministic
linear time. For quicksort choosing the median as pivot keeps the O(n
log n) average running time and brings
On Jul 8, 2009, at 03:32 , John Ky wrote:
| /export/home/a-m/joky/ghc-6.8.2/utils/ghc-pkg/ghc-pkg.bin
--global-conf /export/home/a-m/joky/.tools/ghc-6.8.2/lib/ghc-6.8.2/
package.conf update - --force
ld.so.1: ghc-pkg.bin: fatal: libm.so.2: version `SUNW_1.2' not found
(required by
file
Timo B. Hübel wrote:
Visit Hayoo! here: http://holumbus.fh-wedel.de/hayoo
Additionally, we have again updated the search index. It contains all packages
from Hackage as well as gtk2hs as of 06.07.2009, a total of 111.946 function
and type definitions.
Is it possible that coverage has
Hello!
Two weeks passed and it is about time to release darcs 2.3 beta 2 (it's already
a day late, sorry about that).
As with beta 1, there is only a single installation package for this release of
darcs: cabalised source. (Please note that the final version with also come
with the legacy
Hi,
I'm wondering what a good example of why laziness enhances composability
would be.
I'm specifically looking for something that can't implemented in Python with
iterators (at least not elegantly), but can actually be implemented in
Haskell.
Thanks,
Cristiano
Hello,
A wonderful, and practical example, is the techniques in this modular lazy
search paper:
http://web.cecs.pdx.edu/~apt/jfp01.ps
They build simple solvers, like backtracking, backjumping, etc. and
then compose them together like: bt . bj
The techniques are very much based on laziness.
On 9 Jul 2009, at 14:55, Cristiano Paris wrote:
Hi,
I'm wondering what a good example of why laziness enhances
composability would be.
I'm specifically looking for something that can't implemented in
Python with iterators (at least not elegantly), but can actually be
implemented in
Thank you for your suggestions!
C.
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As a joke, I wrote an instance of Alternative for IO actions:
{-# LANGUAGE ScopedTypeVariables #-}
module Main where
import Control.Applicative
import Control.Exception
instance Alternative IO where
empty = undefined
x | y = handle (\ (_ :: SomeException) - y) x
This would allow to write IO
Hello Cristiano,
Thursday, July 9, 2009, 4:55:09 PM, you wrote:
the best known example is chessmate implementation in Wadler's why
functional programming matter
but i don't know much about Python iterators, so can't say what is
difference. may be its' only simplicity since lazy lists is looks
Hi,
i find the current www.haskell.org frontpage quite overwhelming.
Compare it for example with the home pages of other programming languages :
http://caml.inria.fr/
http://factorcode.org/
http://sbcl.sourceforge.net/
http://www.ruby-lang.org/en/
http://www.falconpl.org/
Here is my sketch of
On Thu, 9 Jul 2009, Cristiano Paris wrote:
As a joke, I wrote an instance of Alternative for IO actions:
{-# LANGUAGE ScopedTypeVariables #-}
module Main where
import Control.Applicative
import Control.Exception
instance Alternative IO where
empty = undefined
x | y = handle (\ (_ ::
On Thu, Jul 9, 2009 at 3:42 PM, Edward Kmett ekm...@gmail.com wrote:
Hrmm. This should probably be made consistent with the MonadPlus instance
for IO, so
empty = ioError (userError mzero)
I agree. Of course, that was only a first attempt :)
Cristiano
On Thu, Jul 9, 2009 at 3:42 PM, Bulat Ziganshin
bulat.zigans...@gmail.com wrote:
Hello Cristiano,
Thursday, July 9, 2009, 4:55:09 PM, you wrote:
the best known example is chessmate implementation in Wadler's why
functional programming matter
but i don't know much about Python iterators,
2009/7/9 hask...@kudling.de:
Hi,
i find the current www.haskell.org frontpage quite overwhelming.
Compare it for example with the home pages of other programming languages :
http://caml.inria.fr/
http://factorcode.org/
http://sbcl.sourceforge.net/
http://www.ruby-lang.org/en/
Bulat Ziganshin wrote:
Hello Cristiano,
Thursday, July 9, 2009, 4:55:09 PM, you wrote:
the best known example is chessmate implementation in Wadler's why
functional programming matter
Aeh, ... Wadler's - Hughes'
--
Dr. Janis Voigtlaender
http://wwwtcs.inf.tu-dresden.de/~voigt/
Well, you're going to wind up with a lot of cases where you really want a
quantified context, even with just your Functor definition, but in that same
spirit you can build an 'Applicative-like' instance as well.
type family Arg f :: *
type instance Arg [a - b] = [a]
type family Result f :: *
Hrmm. This should probably be made consistent with the MonadPlus instance
for IO, so
empty = ioError (userError mzero)
Otherwse, I'm surprised this isn't already in the standard library.
I'd suggest submitting it to librar...@.
-Edward Kmett
On Thu, Jul 9, 2009 at 9:27 AM, Cristiano Paris
To be honest -- that seems rather nice. Can has in Hackage?
Bob
On 9 Jul 2009, at 15:27, Cristiano Paris wrote:
As a joke, I wrote an instance of Alternative for IO actions:
{-# LANGUAGE ScopedTypeVariables #-}
module Main where
import Control.Applicative
import Control.Exception
instance
Hello haskell,
Thursday, July 9, 2009, 5:54:16 PM, you wrote:
i find the current www.haskell.org frontpage quite overwhelming.
it's rather frequent topic here :)
Here is my sketch of a leaner, more structured Haskell front page:
http://www.haskell.org/haskellwiki/User:Lenny222/Haskell
i
I'm testing iteratee.
This is the possible bug I've found
import Data.Iteratee.IO
import Data.Iteratee.Base
import Data.Iteratee.Char
import System.IO
import Control.Exception
main = do
h - openFile mamma23 ReadWriteMode
hPutStrLn h ciao
hSeek h AbsoluteSeek 0
l -
_
Messenger安全保护中心，免费修复系统漏洞，保护Messenger安全！
http://im.live.cn/safe/
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I find it very to the point and not overwhelming at all : it's easy to
glance over it and find quickly what I want.
Thanks for your feedback.
Most people feel overwhelmed when confronted with more than 7+-2 items:
http://www.smashingmagazine.com/2007/10/09/30-usability-issues-to-be-aware-of/
I have trouble in returning a list of Figures. I want return a type of m
(Maybe [Figure IO]), but the type of dv_findFigure is :: a - Point - s
(Maybe (Figure s)). How can change the code below to get a s (Maybe [Figure
s])?
Thank you in advance!
dv_findFigure :: a - Point - s (Maybe (Figures))
hask...@kudling.de wrote:
Most people feel overwhelmed when confronted with more than 7+-2 items:
http://www.smashingmagazine.com/2007/10/09/30-usability-issues-to-be-aware-of/
This refers to the number of items/things people can remember in their
short-time memory. This has nothing to do with
2009/7/9 hask...@kudling.de:
I find it very to the point and not overwhelming at all : it's easy to
glance over it and find quickly what I want.
Thanks for your feedback.
Most people feel overwhelmed when confronted with more than 7+-2 items:
I've seen book providing a chapters at a glance part, just
before the real table of content.
Such an inverted pyramid is exactly the consequence Nielson draw from the F
shape pattern (http://www.useit.com/alertbox/reading_pattern.html).
And that's my critque: i don't see the most important
I never said we should only expose 7 links.
Take for example the task Find out more about this Haskell i heared about.
You would need to scan the right half of the front page and you need to scan
the left part of the page. There you need to scan About, it could be
explained under Why use
Are there any kind of hard statistics and analytics that we can base
this discussion upon? There is always room for improvement, but
stumbling around in the dark making blind guesses may not be the best
way to go. Although I personally feel that Lenny's proposed page is an
improvement, statistics
ttencate:
Are there any kind of hard statistics and analytics that we can base
this discussion upon? There is always room for improvement, but
stumbling around in the dark making blind guesses may not be the best
way to go. Although I personally feel that Lenny's proposed page is an
On Thu, Jul 9, 2009 at 4:34 AM, Nicolas
Pouillardnicolas.pouill...@gmail.com wrote:
I've looked at your DSL and it looks really neat. While reading I was
wondering if GADTs could help having an even nicer query language.
To be honest, I really only know the name GADT, I don't really know
2009/7/9 Don Stewart d...@galois.com:
ttencate:
Are there any kind of hard statistics and analytics that we can base
this discussion upon? There is always room for improvement, but
stumbling around in the dark making blind guesses may not be the best
way to go. Although I personally feel that
I think it would be best if the page were targeted towards newcomers, and
not as a jump point for resources.
Such a jump page is useful, but not as a homepage. Perhaps
haskell.org/linkswould be a better place for such a thing.
As an aside, in the current homepage, the Haskell description is
ttencate:
On Thu, Jul 9, 2009 at 18:33, Don Stewartd...@galois.com wrote:
ttencate:
Are there any kind of hard statistics and analytics that we can base
this discussion upon? There is always room for improvement, but
stumbling around in the dark making blind guesses may not be the best
Hello Don,
Thursday, July 9, 2009, 8:33:17 PM, you wrote:
FWIW, the current layout is actually based on previous analysis of Popular
Pages a few years ago, so that we have O(1) access to key resources.
yes, and it means that page is optimized for regular Haskell users
what is proposed,
By the way, the most valuable pixels, right at the top of the page,
are wasted on wiki stuff. Compare
http://www.haskell.org/
with, for example,
http://www.ruby-lang.org/
http://python.org/
If, like the consensus seems to be, the page should be made more
friendly to beginners (who are unlikely to
bulat.ziganshin:
Hello Don,
Thursday, July 9, 2009, 8:33:17 PM, you wrote:
FWIW, the current layout is actually based on previous analysis of Popular
Pages a few years ago, so that we have O(1) access to key resources.
yes, and it means that page is optimized for regular Haskell users
Hello Don,
Thursday, July 9, 2009, 8:58:48 PM, you wrote:
Newbies:
http://haskell.org
Everything regular users need at fingertips
http://dashboard.haskell.org/
yes, my vision is that newbies will go to homepage, from google search
or by typing haskell.org. we cannot expect that
On Thu, Jul 9, 2009 at 10:00 AM, Thomas ten Cate ttenc...@gmail.com wrote:
By the way, the most valuable pixels, right at the top of the page,
are wasted on wiki stuff. Compare
http://www.haskell.org/
with, for example,
http://www.ruby-lang.org/
http://python.org/
The thing I like the
On Thursday 09 July 2009, Cristiano Paris wrote:
Thanks. In fact, I was stuck trying to find an example which couldn't
be written using Python's iterators. The only difference coming up to
my mind was that Haskell's lists are a more natural way to express a
program relying on laziness. That
The c2hs documentation at
http://www.cse.unsw.edu.au/~chak/haskell/c2hs/docu/implementing.html#id314947
gives me an example to follow for this case:
{#fun notebook_query_tab_label_packing as ^
`(NotebookClass nb, WidgetClass cld)' =
{notebook `nb',
widget `cld'
On Thursday 09 July 2009, you wrote:
2009/7/9 Marcin Kosiba marcin.kos...@gmail.com:
I thought I'll go the smart way and rely on the Python yield construct
to do a CPS transformation of my code.
While this worked to a certain extent, composability was a
problem, because any
On Thu, Jul 9, 2009 at 3:11 PM, Derek Elkins derek.a.elk...@gmail.comwrote:
On Thu, Jul 9, 2009 at 12:31 PM, Jason Dagitda...@codersbase.com wrote:
On Thu, Jul 9, 2009 at 10:00 AM, Thomas ten Cate ttenc...@gmail.com
wrote:
By the way, the most valuable pixels, right at the top of the
IMO, causing a segfault in the interpreter is more than just a DOS
vulnerability :)
On Thu, Jul 9, 2009 at 6:11 PM, Derek Elkins derek.a.elk...@gmail.comwrote:
On Thu, Jul 9, 2009 at 12:31 PM, Jason Dagitda...@codersbase.com wrote:
On Thu, Jul 9, 2009 at 10:00 AM, Thomas ten Cate
On Thu, Jul 9, 2009 at 12:31 PM, Jason Dagitda...@codersbase.com wrote:
On Thu, Jul 9, 2009 at 10:00 AM, Thomas ten Cate ttenc...@gmail.com wrote:
By the way, the most valuable pixels, right at the top of the page,
are wasted on wiki stuff. Compare
http://www.haskell.org/
with, for
On Thu, Jul 9, 2009 at 5:17 PM, Jason Dagitda...@codersbase.com wrote:
On Thu, Jul 9, 2009 at 3:11 PM, Derek Elkins derek.a.elk...@gmail.com
wrote:
On Thu, Jul 9, 2009 at 12:31 PM, Jason Dagitda...@codersbase.com wrote:
On Thu, Jul 9, 2009 at 10:00 AM, Thomas ten Cate
Hi,
I've developed this commercial app in Haskell with all of the business
logic coded in SQL with the help of haskelldb. Some of the intermediate
results (of queries) I had to manifest in extra tables because the initial
query was expensive, the intermediate result would be the source
I like the Haskell page the way it is.
The O'Caml web page, is, by comparison,
infuriatingly unhelpful.
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Hi Paolino.
What's happening is reading [Char] uses the Storable instance for Char
which is 32-bit. Thus, you get gibberish. The below does what you want,
by reading Word8s and converting them.
import Control.Exception
import Data.Char
import Data.Iteratee.IO
import Data.Iteratee.Base
import
On Thu, Jul 9, 2009 at 6:12 PM, Derek Elkinsderek.a.elk...@gmail.com wrote:
I'm not a newbie and I don't use the front page terribly often, but I
do like most of the links that are on it. The Ruby page is certainly
prettier, but the layout of the Haskell page is fine in my opinion;
the
Max Rabkin wrote:
On Sat, Jul 4, 2009 at 8:38 PM, Andrew
Coppinandrewcoppin at btinternet.com wrote:
A few reasons:
1. I never knew it existed. ;-)
A good reason. However, it's good to do a quick search over Hackage
before uploading (or before writing) so you know what's out there.
Also,
Ignoring the rest of the thread, but jumping in here...
hask...@kudling.de wrote:
For the hompage we're talking about, glancing is even simpler since
everything is on the same page and you can scroll it quite easily.
I don't agree that everything on one page makes comprehension easier.
I'm
Rick R wrote:
As an aside, in the current homepage, the Haskell description is outweighed
by the link menu on the left. IMO the reader's eyes should move from the
title, to the description, then either down or left. Currently my attention
is split evenly between the link menu and the
Don Stewart wrote:
ttencate:
On Thu, Jul 9, 2009 at 18:33, Don Stewartd...@galois.com wrote:
ttencate:
Are there any kind of hard statistics and analytics that we can base
this discussion upon? There is always room for improvement, but
stumbling around in the dark making blind guesses may not
On Thu, 9 Jul 2009, rocon...@theorem.ca wrote:
You can use by lib without worrying about the CIE. You can use my library
without ever importing or using the word CIE. However, the CIE stuff is
there for those who need it.
Perhaps I (maybe with some help) need to make a tutorial on the
Jeff Wheeler wrote:
I suspect most people who like the Ruby page see the Ruby
is... section as especially effective at introducing the language,
and the random snippet is a simple way to show off a bit of code
before they dive into a tutorial.
I'll agree that that part is slick.
The rest of
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