package derive-2.3.0.2-ad85bd58710fede3f840a467e84c403e is unusable
due to missing or recursive dependencies:
haskell-src-exts-1.9.4-e0f8c55bea9fc97376aa3598dfdca6d6
package derive-2.4.1-415d44d2f93198aab5dff67866c17b64 is unusable due
to missing or recursive dependencies:
On Fri, Nov 12, 2010 at 03:56:26PM -0800, Michael Litchard wrote:
I've been working on a project that requires me to do screen scraping.
When I first started this, I worked off of other people's examples.
Not one used regex. By luck I found someone at work to help me along
this project. His
Hey all,
While trying to get a commit pushed for Yesod[1], Alexander Dunlap
pointed out one of his programs didn't work with the new code. After
some investigation, I was able to reproduce the bug with the following
code snippet:
{-# LANGUAGE TypeFamilies #-}
data family Foo a
data Bar = Bar
On 13/11/2010, at 9:33 AM, Malcolm Wallace wrote:
On 12 Nov 2010, at 20:21, Andrew Coppin wrote:
On 11/11/2010 08:43 PM, Richard O'Keefe wrote:
If length, map, and so on had always been part of a Sequence
typeclass, people would not now be talking about
It's always puzzled me that
Yves Parès schrieb:
I think this idea is a stairway to duck typing.
I exagerate, of course, but here is my point:
It shouldn't be difficult to make a class:
class HasName a where
name :: a - String
or
class Name a where
name :: Accessor a String
That gives you read and write access
Hi cafe,
I wounder if it is possible to tell a haskell system that two computations
with side effects could be executed concurrently.
Here is an affected example:
Suppose two people want to compare their age, but do not want to leak their
personal information. The following program reads one
i reinstalled cabal and reinstalled derive package and that fixed it.
On Sun, Nov 14, 2010 at 1:40 AM, Anatoly Yakovenko
aeyakove...@gmail.com wrote:
package derive-2.3.0.2-ad85bd58710fede3f840a467e84c403e is unusable
due to missing or recursive dependencies:
Hmm, strange. I have a project that uses data families with dozens of
constructors per clause/instantiation of the type function. I use GADT
syntax to define them though as they also refine one of the parameter type
variables. Never had any issues with it, although I haven't tried building
that
On 12/11/2010, at 6:06 PM, Sebastian Fischer wrote:
As others have pointed out, type classes are insufficient for overloading
record labels because they do not cover record updates.
How can we add a special kind of overloading for record labels that also
works for updates? Maybe like
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
On 11/6/10 23:09 , wren ng thornton wrote:
On 11/6/10 6:20 AM, Reiner Pope wrote:
I was aware of this condition, but I'm not precisely sure it addresses
my requirements. When you run cabal install some-package, cabal
reads all version constraints
Oops. It's right there on the site. My eyes skipped over it for some reason.
On Sat, Nov 13, 2010 at 2:11 PM, Luke Palmer lrpal...@gmail.com wrote:
Is the source code public, so I can run it on my own machine?
Luke
Hi all,
My masters project Zeno was recently mentioned on this mailing
However:
You can express a property such as takeWhile p xs ++ dropWhile p xs
=== xs and it will prove it to be true for all values of p :: a -
Bool and xs :: [a], over all types a, using only the function
definitions.
That is surprising, given that this property does not seem to be true
Shpider is a web automation library for Haskell. It allows you to
quickly write crawlers, and for simple cases ( like following links )
even without reading the page source.
Shpider is on hackage at http://hackage.haskell.org/package/shpider
Shpider development repository is now on github at
On 13 November 2010 21:46, Daniel Fischer daniel.is.fisc...@web.de wrote:
On Saturday 13 November 2010 03:26:46, wolf python london wrote:
hi ,folks ,
I'm a newbie of haskell and learn haskell using the textbook Real
World Haskell.
in the page 201,
ghci good food =~ .ood :: [String]
On Saturday 13 November 2010 03:26:46, wolf python london wrote:
hi ,folks ,
I'm a newbie of haskell and learn haskell using the textbook Real
World Haskell.
in the page 201,
ghci good food =~ .ood :: [String]
Should be
good food =~ .ood :: [[String]]
I think. I don't know if it was an
Hmm. It works with HEAD (and hence I believe with the 7.0.1 RC2). It looks
similar to http://hackage.haskell.org/trac/ghc/ticket/4174, which is fixed.
Anyway I've added it as a regression test, so it should never go wrong again.
Thanks for mentioning it.
Simon
| -Original Message-
Hello,
I have this strange problem, with the same program (simple) behaving
differently when run from console and from WinGHCi.
Platform is Windows XP. Haskell Platform 2.0.0.
The program :
import IO
import Data.Maybe
tfind s = lookup (head s) $ zip \232\222 12
main = do
h -
Hi,
I'm trying to follow some examples of HUnit from a webpage. Basically I want my
_application_ code to call the error function when a certain condition is met
(namely when a supplied String to a function is longer than 80 characters).
I want my _test_ code to catch this error.
I've been working with Haskell's Date.Time modules to parse a date like
12-4-1999 or 1-31-1999. I tried:
parseDay :: String - Day
parseDay s = readTime defaultTimeLocale %m%d%Y s
And I think it wants my months and days to have exactly two digits instead
of 1 or 2...
What's the proper way to do
Hi,
Can someone provide me the solution to the following riddle that Ralf
asked in his lecture at
http://channel9.msdn.com/Shows/Going+Deep/C9-Lectures-Dr-Ralf-Lmmel-Advanced-Functional-Programming-Evolution-of-an-Interpreter
Riddle: define a custom made monad (only involving (-) and Either
Hello,
I have this strange problem, with the same program (simple) behaving
differently when run from console and from WinGHCi.
Platform is Windows XP. Haskell Platform 2.0.0.
The program :
import IO
import Data.Maybe
tfind s = lookup (head s) $ zip \232\222 12
main = do
h -
Hello again,
So I followed Kevin's suggestion and installed MinGW along with gcc
and autoconf tools needed by hs-plugins. Then it failed with the
following error:
$ cabal install --enable-documentation plugins
Resolving dependencies...
Configuring plugins-1.5.1.4...
checking build system type...
On Wed, Nov 10, 2010 at 5:48 PM, Simon Marlow marlo...@gmail.com wrote:
[...] So we should
say there are a few things that you can do that guarantee not to call any
interruptible operations:
- IORef operations
- STM transactions that do not use retry
- everything from the Foreign.*
Parallel Haskell project underway
GHC HQ and Well-Typed are pleased to report that work has started on
the MSR-funded project to push the real-world use of parallel Haskell.
We will be working with four industrial partners over the next two
years, with the aim of demonstrating that parallel
On Sat, Nov 13, 2010 at 4:35 PM, Alex Baranosky
alexander.barano...@gmail.com wrote:
I've been working with Haskell's Date.Time modules to parse a date
like 12-4-1999 or 1-31-1999. I tried:
parseDay :: String - Day
parseDay s = readTime defaultTimeLocale %m%d%Y s
And I think it wants my
Two significant points which have emerged from the TDNR thread are:
-The wiki page combines two orthogonal proposals: type-directed name resolution, which requires no special syntax, and
the x.f syntax, which does not require TDNR.
-Implementing both proposals may be a desired fix for the
Sorry, I forgot to mention which compiler I was working with: 6.12.3.
I'm glad to hear it's working with 7.
Michael
On Mon, Nov 15, 2010 at 4:58 PM, Simon Peyton-Jones
simo...@microsoft.com wrote:
Hmm. It works with HEAD (and hence I believe with the 7.0.1 RC2). It looks
similar to
On 15/11/10 15:23, Dmitry Astapov wrote:
== Dragonfly ==
http://www.dragonfly.co.nz/
Participants: Finlay Thompson, Edward Abraham
Cloudy Bayes: Hierarchical Bayesian modeling in Haskell
The Cloudy Bayes project aims to develop a fast Bayesian model
fitter that takes advantage of
Hi,
is haskell.org being updated or, as I fear, Haskell's HQ has been
overrun by a mob of PHPers ?
If so, I am ready to fight !
titto
P.S.
Just need to find my Excalibur, oh god, the wife just sent it to the
Dry Cleaner.
--
Pasqualino Titto Assini, Ph.D.
http://quid2.org/
Dear Haskellers,
We're looking for outstanding candidates for an internship in Spring 2011.
The internship will be in a suburb of Boston (Hudson, MA). Graduate
students and talented undergraduates are welcome to apply, but time is a bit
short.
We are a small research group run directly by the
Hi Felipe,
On Tue, Nov 9, 2010 at 3:53 PM, Felipe Almeida Lessa
felipe.le...@gmail.com wrote:
On Tue, Nov 9, 2010 at 8:10 AM, C K Kashyap ckkash...@gmail.com wrote:
] I think I can restate my problem like this ---
]
] If I have a list of actions as follows -
]
] import Data.Word
] import
Well basically, I haven't update my Haskell libraries for some time now
(around a month) so when I finally got around to updating my Haskell
packages (which are installed through Archlinux's AUR) my GHC installation
broke (again). This has been happening for some time now (I have been having
this
Is the source code public, so I can run it on my own machine?
Luke
Hi all,
My masters project Zeno was recently mentioned on this mailing list so
I thought I'd announce that I've just finished a major update to it,
bringing it slightly closer to being something useful. Zeno is a fully
I still don't understand what intent typing is, but this particular
problem is discussed (with a type-based, statically checked solution)
at
http://blog.moertel.com/articles/2006/10/18/a-type-based-solution-to-the-strings-problem
--Max
On Mon, Nov 15, 2010 at 17:17, Marcus Sundman
Update: The job requisition number is 584943. You can submit your full
application here:
https://intel.taleo.net/careersection/1/jobdetail.ftl?lang=enctx=1job=584943
Please include a cover-letter explaining why you are great for this job.
Cheers,
-Ryan
P.S. It looks like one link below
I've been working on a project that requires me to do screen scraping.
If you are screen scraping HTML I think tagsoup is a very good choice.
The use of tagsoup means that you have a real HTML 5 compliant parser
underneath, and then you can use whatever technique you wish to split
up the page
This is an example of what happens
Proceed with installation? [Y/n] Y
checking package integrity...
(1/1) checking for file conflicts
[##] 100%
ghc-pkg: unregistering gio-0.11.1 would break the following packages:
ltk-0.8.0.8 gtksourceview2-0.12.1 gtk-0.11.2 (use
How am I supposed to write an exception handle for an invocation
of System.IO.SaferFileHandles.openFile?
Currently, I have got this:
case req of
Open path - do
handle -openFile (asAbsPath path) ReadMode
liftIO $ forcePut result Success
run handle
Follwing
On Fri, Nov 12, 2010 at 22:48, Jonathan Geddes
geddes.jonat...@gmail.com wrote:
Records do leave quite a bit to be desired. But does anybody actually have a
concrete alternative proposal yet?
A few months ago I proposed a couple of extensions [1] on -cafe.
[snip]
Consider what this would
From: Jiansen He jianse...@googlemail.com
Hi cafe,
I wounder if it is possible to tell a haskell system that two computations
with side effects could be executed concurrently.
Here is an affected example:
Suppose two people want to compare their age, but do not want to leak their
First question. As I saw in sources, both hxt and haxml uses [Char]'s.
this is very inefficient. I want to know, does any effective parser for
haskell, written in haskell, exists.
The TagSoup parser can generate ByteString syntax trees - but they're
quite a bit slower than [Char] versions. I
Hi,
I'm fairly new to Haskell and recently came across some programming
tricks for reducing monadic overhead, and am wondering what
higher-level concepts they map to. It would be great to get some
pointers to related work.
Background:
I'm a graduate student whose research interests include
On 13 November 2010 16:46, Neil Mitchell ndmitch...@gmail.com wrote:
I've been working on a project that requires me to do screen scraping.
If you are screen scraping HTML I think tagsoup is a very good choice.
The use of tagsoup means that you have a real HTML 5 compliant parser
underneath,
Hello,
In experimenting with HList's very impressive extensible records, I
discovered that the field access operators (#) and (.!.) have right
associativity; this means I can't write (r # f1 # f2) to access field f2
of the record stored in field f1 of r. If (#) and (.!) had
left-associativity
On 13 November 2010 20:16, Pasqualino Titto Assini
tittoass...@gmail.com wrote:
is haskell.org being updated or
It's back up now. As far as I'm aware, it is being updated. But I'm
not sure on the progress of it and whether the server transfer is
related.
If so, I am ready to fight !
Lambda
I was wondering, Zeno capable of proving just equational statements, or is
it able to prove more general statements about programs? In particular, it
would be interesting if Zeno would be able to prove that a function is total
by verifying that it uses only structural (inductive) recursion (on
I've came upon very a strange situation with memory consumption. The
smallest test case I've been able to come up with is the following:
import Data.List
wtf d = head . dropWhile ( 10^100) . map (*d) $ enumFrom 2
main = do
print $ wtf 1
print $ wtf 2 -- Everything is ok without this
On Nov 15, 2010, at 9:43 AM, Ling Yang wrote:
Specifically: There are some DSLs that can be largely expressed as
monads,
that inherently play nicely with expressions on non-monadic values.
This, to me, is a big hint that applicative functors could be useful.
Every monad is an
= The haskell.org committee has formed =
http://haskellorg.wordpress.com/2010/11/15/the-haskell-org-committee-has-formed/
In recent years, haskell.org has started to receive assets, e.g. Google
Summer Of Code funds, donations for Hackathons, and a Sparc machine for
use in GHC development. We
On Sat, Nov 13, 2010 at 2:55 PM, Petr Prokhorenkov
prokhoren...@gmail.com wrote:
Is there any way to overcome this?
You can add
{-# NOINLINE wtf #-}
That will prevent the sharing. But I'm not sure if this is the best solution.
Cheers,
--
Felipe.
Hi!
On Mon, Nov 8, 2010 at 1:50 AM, Felipe Almeida Lessa
felipe.le...@gmail.com wrote:
(I won't answer your main question, I'll just write some notes on your
current code.)
Thanks. This also helped.
But is it possible to define a Monad like I described? So that all
actions would be wrapped in
Well, I guess you could try something like:
{-# LANGUAGE GADTs #-}
import Control.Exception (bracketOnError)
import Control.Monad ((=))
-- from package 'operational'
import Control.Monad.Operational
data BracketedOperation a where
Bracketed :: IO a - (a - IO b) - BracketedOperation a
On Mon, Nov 15, 2010 at 12:43 PM, Ling Yang ly...@cs.stanford.edu wrote:
Specifically: There are some DSLs that can be largely expressed as monads,
that inherently play nicely with expressions on non-monadic values.
We'd like to use the functions that already work on the non-monadic
values for
On Mon, Nov 8, 2010 at 1:40 AM, Mitar mmi...@gmail.com wrote:
Hi!
I have a class Neuron which has (among others) two functions: attach
and deattach. I would like to make a way to call a list/stack/bunch of
attach functions in a way that if any of those fail (by exception),
deattach for
This, to me, is a big hint that applicative functors could be useful.
Indeed, the ideas here also apply to applicative functors; it is just the
lifting primitives that will be different; instead of having liftMN, we can
use $ and * to lift the functions. We could have done this for Num and
See my reply to Alex's post for my perspective on how this relates to
applicative functors, reproduced here:
This, to me, is a big hint that applicative functors could be useful.
Indeed, the ideas here also apply to applicative functors; it is just the
lifting primitives that will be
Hood on Hackage is an interesting way to see intermediate data structures.
{-# LANGUAGE NoMonomorphismRestriction #-}
-- Fold Behaviour Observed
module Folding where
-- See Hood on Hackage
import Observe
import Data.List
n = 10::Int
fr = foldr (observe Add (+)) 0 [1..n]
On Sun, Nov 7, 2010 at 7:40 PM, Mitar mmi...@gmail.com wrote:
I have a class Neuron which has (among others) two functions: attach
and deattach. I would like to make a way to call a list/stack/bunch of
attach functions in a way that if any of those fail (by exception),
deattach for previously
On 11/13/2010 08:55 AM, Petr Prokhorenkov wrote:
import Data.List
wtf d = head . dropWhile ( 10^100) . map (*d) $ enumFrom 2
main = do
print $ wtf 1
print $ wtf 2 -- Everything is ok without this line
Is there any way to overcome this?
I think this phenomenon is called the full
On 10-11-14 07:36 PM, Jiansen He wrote:
Hi cafe,
I wounder if it is possible to tell a haskell system that two
computations with side effects could be executed concurrently.
Here is an affected example:
Suppose two people want to compare their age, but do not want to leak
their personal
On Mon, Nov 15, 2010 at 6:43 PM, Ling Yang ly...@cs.stanford.edu wrote:
...
One alternate way of doing this, however, is instancing the
typeclasses of the ordinary values with their monadic versions:
instance (Num a) = Num (Prob a) where
(+) = liftM2 (+)
(*) = liftM2 (*)
I like your autolifting stuff, and the runnable concept.
2010/11/15 Ling Yang ly...@cs.stanford.edu
See my reply to Alex's post for my perspective on how this relates to
applicative functors, reproduced here:
This, to me, is a big hint that applicative functors could be useful.
Indeed,
I haven't watched the lecture. But what does he mean survive? Does
it mean to do anything that you can do with mtl?
On Mon, Nov 15, 2010 at 12:53 AM, C K Kashyap ckkash...@gmail.com wrote:
Hi,
Can someone provide me the solution to the following riddle that Ralf
asked in his lecture at
On Sun, Nov 14, 2010 at 12:38 PM, Florian Weimer f...@deneb.enyo.de wrote:
How am I supposed to write an exception handle for an invocation
of System.IO.SaferFileHandles.openFile?
Currently, I have got this:
case req of
Open path - do
handle -openFile (asAbsPath path) ReadMode
Hello Arnaud,
I also faced this problem with the plugins package. This particular
error comes from the backslashes in the ghc library directory not being
escaped. But even after patching this, I had trouble with missing
imports and some other stuff. It seams that this package is not much
Hi!
On Mon, Nov 15, 2010 at 9:07 PM, C. McCann c...@uptoisomorphism.net wrote:
Isn't this mostly a reimplementation of mapM? Given a list of [IO
Growable], you map over it to put a bracket around each one, then
sequence the result
No. There is a trick. It stacks up attach and deattach. So if
Hi!
Felipe and Bas, thank you for your suggestions. They really opened two
new worlds to me. ;-) I didn't know about those libraries.
I was hopping of succeeding making a bracketing monad by hand, to
learn something and to make my first monad. But was not successful. I
hope those approaches with
On Mon, Nov 15, 2010 at 9:44 PM, Mitar mmi...@gmail.com wrote:
I was hopping of succeeding making a bracketing monad by hand, to
learn something and to make my first monad. But was not successful. I
hope those approaches with libraries will be a good guide to me.
My approach using
Hi!
My approach using 'operational' package is equivalent to creating your
own monad. The beauty of 'operational' is that you don't need to
worry about the pumbling of the monad, you just need to specify what
to do with your operations.
True. Approach with operational is really beautiful.
On Mon, Nov 15, 2010 at 11:27 PM, Brian Bloniarz
brian.bloni...@gmail.com wrote:
So I think you're seeing bug http://hackage.haskell.org/trac/ghc/ticket/917
where the increased sharing only leads to space leaks. You could
try the workaround, passing -fno-full-laziness (it might need to
come
On Mon, Nov 15, 2010 at 10:15 PM, Mitar mmi...@gmail.com wrote:
True. Approach with operational is really beautiful. And it is
really great when you want things done. But for me, Haskell novice who
wants to learn more, it hides too much. So it is probably something I
would use in my code, but
On Nov 15, 2010, at 4:15 PM, Mitar wrote:
True. Approach with operational is really beautiful. And it is
really great when you want things done. But for me, Haskell novice who
wants to learn more, it hides too much. So it is probably something I
would use in my code, but on the other hand I
On Tue, Nov 16, 2010 at 12:50 AM, Felipe Almeida Lessa
felipe.le...@gmail.com wrote:
That said, I don't know what 'regions' may do for you that the simple
monad I presented doesn't. Bas, what are the advantages?
My suggestion to use regions is based on an assumption which I'm not
sure is
On Tue, Nov 16, 2010 at 3:58 AM, Luke Palmer lrpal...@gmail.com wrote:
I haven't watched the lecture. But what does he mean survive? Does
it mean to do anything that you can do with mtl?
Yes ... to understand monad transformers better, he suggested trying
to wrap a monad inside another (I am
cafe,
Data Constructors and Type Constructors don't share the same
namespace. You see code like the following all the time:
data MyRecord = MyRecord {...}
This is possible because Data Constructors are used in different parts
of the code than Type Constructors so there's never any ambiguity.
2 seconds after sending I realized the issue is in module exports:
Module String where (String(..))
is that exporting some concrete ADT with all of its constructors or an
abstract type class with all of its methods?
Its too bad that Classes and ADTs overlap in export syntax and as such
must
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Hash: SHA1
On 11/8/10 04:52 , Ivan Lazar Miljenovic wrote:
I'm not sure how MacPorts does packaging, so you may require to
install a -dev or development version of glut to get the relevant
headers and library files.
MacPorts always builds from source, so
OK, here is a short summary:
- installed MinGW + GCC 4.5 toolchain
- downloaded latest code from darcs
- Run ./Setup.lhs configure
- got another failure
Setup.lhs:2:2:
Warning: In the use of `defaultUserHooks'
(imported from Distribution.Simple):
Deprecated: Use
Personally I gave up on installing haskell packages through AUR, I
pretty much stick to Cabal now.
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
If I were to guess, I'd say it's because there are two major spaces in
Haskell, the type level and the value level. They never interact directly
(their terms are never juxtaposed) so there's not much chance for confusion.
Typeclass constructors and type constructors do however live in the same
Yeah I used to do that as well, but then that kind of fails on packages that
provides both libraries and binaries (and other issues as well)
On 16/11/2010 4:53 PM, James Sanders jimmyjaz...@gmail.com wrote:
Personally I gave up on installing haskell packages through AUR, I
pretty much stick to
I'm guessing this did *not* make it into 7.0.1, correct? Is there
still a chance that it will be in 7.0.2, and therefore the next HP
release?
Michael
On Fri, Nov 12, 2010 at 10:38 AM, Simon Peyton-Jones
simo...@microsoft.com wrote:
Good point. I've done this. (Ian, could you merge)
Fri Nov 12
On Sun, Nov 14, 2010 at 00:32, Mathew de Detrich dete...@gmail.com wrote:
This is an example of what happens
Proceed with installation? [Y/n] Y
checking package integrity...
(1/1) checking for file conflicts
[##] 100%
ghc-pkg: unregistering gio-0.11.1 would
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