On Mon, Aug 2, 2010 at 4:12 PM, Phyx loneti...@gmail.com wrote:
I've tried to use leksah but some minor annoying things make it unusable for
me.
I'm curious, what are those minor annoying things?
Trying code completion in comments on string constants, for example.
Code completion makes the
The following message was sent to me, but was apparently intended for
this thread, so I am forwarding it to the Haskell-Cafe Mailing List:
On Mon, Aug. 2, 2010 at 11:44 PM, Gordon Sommers gordon.somm...@gmail.com
wrote:
This looks pretty neat! The website would benefit from one or two
Stefan Holdermans wrote:
The point of this discussion is that the Eval constraint needs to be
on one
of the functions. So I tried to specify that (x - Int) and (y -
Int) are
different types despite x and y being the same type, because one of
them has
an Eval constraint. This may be a
Janis,
So, basically, we are annotating function
types, what is IIRC exactly what Janis and David are doing. (I hope
Janis corrects me if I'm wrong here).
Wrong only in that David's name is Daniel. :-)
Ah, I am terribly sorry. I just shouldn't type e-mails after having no more
than a
Hi,
DSTM is an implementation of a robust distributed Software Transactional Memory
(STM) library for Haskell. Many real-life applications are distributed by
nature. Concurrent applications may profit from robustness added by
re-implementation as distributed applications. DSTM extends the STM
This is very cool, thanks for writing it. I will try it when I get home tonight.
On 3 August 2010 10:35, Frank Kupke f...@informatik.uni-kiel.de wrote:
Hi,
DSTM is an implementation of a robust distributed Software Transactional
Memory (STM) library for Haskell. Many real-life applications
Tom Davies wrote:
I find it convenient sometimes to convert a Maybe
value to an Either
maybeToEither = flip maybe Right . Left
Christopher Done wrote:
It's available in MissingH
While useful, I think its ubiquity to simplicity ratio is not
high enough to justify either depending on MissingH
Yitzchak Gale g...@sefer.org writes:
Tom Davies wrote:
I find it convenient sometimes to convert a Maybe
value to an Either
maybeToEither = flip maybe Right . Left
Remember, some people don't like flip! :p
maybeToEither = (`maybe` Right) . Left
While useful, I think its ubiquity to
On Sat, Jul 31, 2010 at 12:07 PM, Rustom Mody rustompm...@gmail.com wrote:
Do most people who work with haskell use emacs/vi/eclipse or something
else??
I used Emacs, as I used to in other langauages.( mainly on Linux)
When switching to Mac Ox, I Re tried Leksah at 0.8 , and Now Am sticking
I wrote:
maybeToEither = flip maybe Right . Left
Ivan Lazar Miljenovic wrote:
Remember, some people don't like flip! :p
maybeToEither = (`maybe` Right) . Left
Yes, absolutely!
...go ahead and upload it to Hackage
Just give it a good name, rather than fooToolkit, barToolkit, etc.
How
On 03/08/10 05:32, Gregory Crosswhite wrote:
I am pleased to announce the release of the package approximate-equality,
which provides newtype wrappers that allow one to effectively override the equality
operator of a value so that it is/approximate/ rather than/exact/. The wrappers use
type
On Tue, Aug 3, 2010 at 7:27 AM, Neil Brown nc...@kent.ac.uk wrote:
I like the look of this. Eq and Ord instances that use epsilon values look
like they will be handy. I have a design question/suggestion. You have:
What properties does Eq need to obey?
Reflexivity: (a == a)
Symmetry: (a ==
Hello!
I'm pleased to announce the release of two new packages:
http://hackage.haskell.org/package/hierarchical-clustering
http://hackage.haskell.org/package/gsc-weighting
'hierarchical-clustering' provides a function to create a dendrogram
from a list of items and a distance function between
Felipe Lessa felipe.le...@gmail.com writes:
Hello!
I'm pleased to announce the release of two new packages:
http://hackage.haskell.org/package/hierarchical-clustering
http://hackage.haskell.org/package/gsc-weighting
'hierarchical-clustering' provides a function to create a dendrogram
On Tue, Aug 3, 2010 at 8:01 AM, Ivan Lazar Miljenovic
ivan.miljeno...@gmail.com wrote:
Felipe Lessa felipe.le...@gmail.com writes:
'hierarchical-clustering' provides a function to create a dendrogram
from a list of items and a distance function between them. The most
common linkage types are
On 3 August 2010 01:34, Richard O'Keefe o...@cs.otago.ac.nz wrote:
There's a thing I'm still finding extremely hard about monads,
and that's how to get into the frame of mind where inventing
things like Monad and Applicative and Arrows is something I could
do myself. Functor, yes, I could
Tom Davies tgdav...@gmail.com wrote:
I find it convenient sometimes to convert a Maybe value to an Either
thus (excuse the syntax, it's CAL, not Haskell):
maybeToEither :: a - Maybe b - Either a b;
maybeToEither errorValue = maybe (Left errorValue) (\x - Right x);
As a side note, this is
On Aug 3, 10:10 am, Ivan Miljenovic ivan.miljeno...@gmail.com wrote:
On 3 August 2010 15:02, rustom rustompm...@gmail.com wrote:
I tried to install pivotal
According to the site I must do:
ghc --make Main -fglasgow-exts -package plugins
I get
cant satisfy package plugins
Which
rustom rustompm...@gmail.com writes:
I am not sure how to resolve this: use cabal install and 'preferably
use a distro'
My preference is that if my distro has a package that I want and the
latest such version (or a maintainer can be prompted to get latest
version in there), then I use the
On Mon, 02 Aug 2010 17:41:02 +0200, Janis Voigtländer
j...@informatik.uni-bonn.de wrote:
Hi,
I am late to reply in this thread, but as I see Stefan has already made
what (also from my view) are the main points:
- Putting seq in a type class makes type signatures more verbose, which
one
Nicolas,
OK, I better understand now where we disagree. You want to see in the type
whether or not the free theorem apply, I want them to always apply when
no call to unsafe function is made.
Implementing your suggestion would make me feel uncomfortable. Turning seq into
an unsafe operations
Nicolas Pouillard schrieb:
- If there is no class instance for function types, then those problems
go away, of course. But it is doubtful whether that would be a viable
solution. Quite a few programs would be rejected as a consequence. (Say,
you want to use the strict version of foldl. That will
Hi again,
Maybe I should add that, maybe disappointingly, I do not even have a
strong opinion about whether seq should be in Haskell or not, and in
what form. Let me quote the last paragraph of an extended version of our
paper referred to earlier:
Finally, a natural question is whether or not
On Sun, Jul 18, 2010 at 3:02 AM, Mark Wotton mwot...@gmail.com wrote:
I've uploaded haskell-src-meta-mwotton, using the development version.
It seems to work fine for my applications. It's a bit of a hack, but I
can't think of a better way to do it for now.
mark
--
A UNIX signature isn't
On Tue, 3 Aug 2010 16:24:54 +0200, Stefan Holdermans ste...@vectorfabrics.com
wrote:
Nicolas,
OK, I better understand now where we disagree. You want to see in the type
whether or not the free theorem apply, I want them to always apply when
no call to unsafe function is made.
Dear Haskell friends,
I like to announce a new version of the style scanner for Haskell source
files at
http://hackage.haskell.org/package/scan
documented under http://projects.haskell.org/style-scanner/
cabal update
cabal install scan
A short description is also here:
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
On 8/3/10 10:24 , Stefan Holdermans wrote:
Implementing your suggestion would make me feel uncomfortable. Turning seq
into an unsafe operations effectively places it outside the language, like
unsafePerformIO isn't really part of the language (in
Hi,
When I try to install haskell platform 64 bit on a x86_64 debian etch I get
the following error after :
make install:
/usr/bin/install -c -m 755 -d /usr/local/lib/ghc-6.12.3/package.conf.d
/usr/local/lib/ghc-6.12.3/ghc-pkg --force --global-conf
/usr/local/lib/ghc-6.12.3/package.conf.d
On 8/3/10 3:27 AM, Neil Brown wrote:
So you can get the same function without needing to add a type-class.
Or is it that you envisage other tolerance specifications besides
Digit? If so, I wonder if this flexibility complicates your API
unnecessarily. If you removed those type-classes and
pieter:
Hi,
When I try to install haskell platform 64 bit on a x86_64 debian etch I get
the
following error after :
make install:
/usr/bin/install -c -m 755 -d /usr/local/lib/ghc-6.12.3/package.conf.d
/usr/local/lib/ghc-6.12.3/ghc-pkg --force --global-conf /usr/local/lib/
OK, so if you do something like
class Container c where
type Element c :: *
then we now have a clean and concise way to discover what type of
element any given container holds. (Regardless of whether it's element
type is parametric, hard-coded, class-constrained or anything else.) I
So I believe the final way to do this, which is not yet implemented,
works something like this:
type family LeftToRight a
type family RightToLeft b
class (LeftToRight a ~ b, RightToLeft b ~ a) = Bijection a b where
...
I agree, the fact that this doesn't work is really dumb.
I used a
On 03.08.2010 21:25, Andrew Coppin wrote:
Now suppose that instead of a container type with an associated element
type, what we want is several pairs of types having a one-to-one
relationship, and we want to be able to traverse that relationship in
either direction. What's the best way to do
On 02/08/10 15:14, Tom Davies wrote:
I find it convenient sometimes to convert a Maybe value to an Either thus
(excuse the syntax, it's CAL, not Haskell):
maybeToEither :: a - Maybe b - Either a b;
maybeToEither errorValue = maybe (Left errorValue) (\x - Right x);
but that seemingly
That is really nice.
The architecture seems to be around a single server that bring lookup
services, so there is a single point of failure. I´m thinking on cloud
computing. Can be extended to have backup servers somehow ?
Alberto.
2010/8/3 Christopher Done chrisd...@googlemail.com
This is
Dear Haskell and Darcs community,
I have written a tool to interactively edit patches, which under the
hood uses the Darcs API. A more catchy introduction, including a
screencast, can be found on
https://www.joachim-breitner.de/blog/archives/425-ipatch,-the-interactive-patch-editor.html
which
On 03/08/2010, at 10:09 PM, Ertugrul Soeylemez wrote:
Tom Davies tgdav...@gmail.com wrote:
I find it convenient sometimes to convert a Maybe value to an Either
thus (excuse the syntax, it's CAL, not Haskell):
maybeToEither :: a - Maybe b - Either a b;
maybeToEither errorValue = maybe
Joachim Breitner m...@joachim-breitner.de writes:
Dear Haskell and Darcs community,
I have written a tool to interactively edit patches, which under the
hood uses the Darcs API. A more catchy introduction, including a
screencast, can be found on
Hi,
Am Mittwoch, den 04.08.2010, 07:42 +1000 schrieb Ivan Lazar Miljenovic:
Joachim Breitner m...@joachim-breitner.de writes:
Dear Haskell and Darcs community,
I have written a tool to interactively edit patches, which under the
hood uses the Darcs API. A more catchy introduction,
Hi all,
I am doing an Intro To Monads talk in September [1]. The audience consists
of experienced non-Haskell developers but they will be familiar with basic
functional concepts (closures, first-class functions etc.).
I am looking for suggestions on how to introduce the concept and its
Hey everyone,
Could someone explain to me the logic behind having unsafe calls block
other threads from executing? It seems to me that if anything it would
make more sense for safe calls to block other threads since the call
can call back into the Haskell runtime, as opposed to unsafe calls
It's a matter of perspective. Either the function you're FFI'ing to is
safe/unsafe or your use of it is safe/unsafe. The FFI spec seems to be using
the former, so if you think that the function you're calling is unsafe
(i.e., can call back into Haskell) then it blocks the world.
But I do think
But you've got it backwards: if the function I am calling can call
back into Haskell (i.e., is marked as safe), then GHC *doesn't* block
the world, but if the function I am calling will never call back into
Haskell (i.e., is marked as unsafe), then GHC *does* block the world.
The reasoning
On Tue, Aug 3, 2010 at 3:06 PM, Gregory Crosswhite
gcr...@phys.washington.edu wrote:
But you've got it backwards: if the function I am calling can call back
into Haskell (i.e., is marked as safe), then GHC *doesn't* block the
world, but if the function I am calling will never call back into
On Tue, Aug 03, 2010 at 02:54:40PM -0700, Gregory Crosswhite wrote:
Could someone explain to me the logic behind having unsafe calls block
other threads from executing? It seems to me that if anything it would
make more sense for safe calls to block other threads since the call
can call back
On 08/03/10 15:22, Evan Laforge wrote:
On Tue, Aug 3, 2010 at 3:06 PM, Gregory Crosswhite
gcr...@phys.washington.edu wrote:
But you've got it backwards: if the function I am calling can call back
into Haskell (i.e., is marked as safe), then GHC *doesn't* block the
world, but if the function
Just think of unsafe in relation to unsafeIndex or something.
It's faster, but you have to be sure the index is in bounds.
Yes, but the whole reason to use unsafe is to get higher performance
at the cost of safety. If the result of calling an unsafe foreign
function is that you *lose*
On 08/03/10 15:23, John Meacham wrote:
It is more an accident of ghc's design than anything, the same mechanism
that allowed threads to call back into the runtime also allowed them to
be non blocking so the previously used 'safe' and 'unsafe' terms got
re-used. personally, I really don't like
On Tue, Aug 3, 2010 at 2:51 PM, aditya siram aditya.si...@gmail.com wrote:
I am doing an Intro To Monads talk in September [1].
...what would you stay away from.
Some things to stay away from:
http://byorgey.wordpress.com/2009/01/12/abstraction-intuition-and-the-monad-tutorial-fallacy/
On 08/03/10 15:33, Evan Laforge wrote:
Just think of unsafe in relation to unsafeIndex or something.
It's faster, but you have to be sure the index is in bounds.
Yes, but the whole reason to use unsafe is to get higher performance
at the cost of safety. If the result of calling an unsafe
Thanks for reminding me. Although I wonder if there is a difference between
drawing metaphors (monads are burritos etc.) and drawing parallels. For
example in the beginning it was useful for me to think of monads (and
typeclasses really) as approximating Java interfaces. Now this parallel dies
As far as I know, it works like this:
unsafe calls are just executed directly, like any other C function
call; as a result, any lightweight haskell threads which were mapped
onto the OS thread in which the call is made are blocked for the
duration of the call; hence why it's a good idea that
O, okay, that makes a LOT more sense! I had thought
that blocking meant that *all* of the *OS* threads were halted before
making the call, but if blocking really just means that the calling
*OS* thread can't do any other work until the call returns (hence
blocking the other *IO*
On Aug 3, 2010, at 4:44 PM, aditya siram wrote:
Thanks for reminding me. Although I wonder if there is a difference between
drawing metaphors (monads are burritos etc.) and drawing parallels.
Since they are experienced developers, your audience will want to know how to
use monads to solve
Today I read this fantastic blog post:
You Could Have Invented Monads! (And Maybe You Already Have.)
http://blog.sigfpe.com/2006/08/you-could-have-invented-monads-and.html
You most probably have seen the post by now, but I just wanted to remind it,
just in case.
Best,
On 3 August 2010 22:51,
As more I learn haskell, I am more interested in this function
programming language. I am intended to more focus on haskell than other
languages like python, Java, or C++. But I am still wonder whether haskell can
do everyting
as other languages do, such as python, perl, Java and C++.
Is there
qiqi789:
As more I learn haskell, I am more interested in this function
programming language. I am intended to more focus on haskell than other
languages like python, Java, or C++. But I am still wonder whether haskell
can do everyting
as other languages do, such as python, perl, Java and
Quoth John Meacham j...@repetae.net,
It is more an accident of ghc's design than anything, the same mechanism
that allowed threads to call back into the runtime also allowed them to
be non blocking so the previously used 'safe' and 'unsafe' terms got
re-used. personally, I really don't like
On Tue, Jul 27, 2010 at 04:08:39PM -0700, Gerald Gutierrez wrote:
Reading the Control.Monad.Error documentation, I see that the Error class
has noMsg and strMsg as its only two functions.
Now, I understand that you can define your own Error instances such as in
example 1 of the
I use Haskell for everything. In fact, I will be approaching my 10
year anniversary of using Haskell as my primary development language
soon.
The only area I have had any trouble with Haskell is doing realtime
music synthesis. And only because the garbage collector is not
realtime friendly. That
On Tue, Aug 3, 2010 at 4:12 PM, Qi Qi qiqi...@gmail.com wrote:
Is there anyone happen to come into any tasks that haskell is not able
to achieve?
Haskell has very limited support for high-level Natural Language
Processing (tokenization, sentence splitting, Named-entity
recognition, etc...).
On 4 August 2010 10:42, Rogan Creswick cresw...@gmail.com wrote:
Haskell has very limited support for high-level Natural Language
Processing [snip]
This isn't a fault of the language, it just
I have some hope that jvm-bridge can be resurrected to bind to
OpenNLP, but that's something I've
On Aug 3, 2010, at 2:51 PM, aditya siram wrote:
I am looking for suggestions on how to introduce the concept and its
implications. I'd also like to include a section on why monads exist
and why we don't really see them outside of Haskell.
Start with functors (things that attach
Hi!
I need to do some image processing for an algorithm. It involves two (well,
three) different kinds of arrays. The result array I'm happy to leave as a
Data.Array for now, since it tends to be bulk updated, and involves Either
with tuples of tuples, and it's easy enough to switch to
The Haddock team has spent the last few months revamping the look of the
generated output. We're pretty close to done, but we'd like to get the
community's input before we put it in the main release.
Please take a look, and then give us your feedback through a short survey
Sample pages:
Alexander == Alexander Solla a...@2piix.com writes:
Alexander On Aug 3, 2010, at 2:51 PM, aditya siram wrote:
I am looking for suggestions on how to introduce the concept and its
implications. I'd also like to include a section on why monads
exist and why we don't really see them
Hi,
Please take a look at this video
http://videoarch1.s-inf.de/FP.2005-SS-Giesl.(COt).HD_Videoaufzeichnung/2005-SS-FP.U09.2005-07-06.HDV.avi
Here Monad's are explained as something that helps making your program
modular. The teacher gives an example implementation of an expression
evaluator with
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