2009/4/28 Thomas Hartman
I suppose this means that the points-free/pattern binding-style
> version is a bit less work for ghc to execute (fewer reductions),
> whereas the version with lambda bound variables is easier to debug.
I don't think there is any (significant) difference between them in
Slides from last week's London HUG http://www.londonhug.net/ talk are
now online. The talk attempts to document some of the tips and tricks
Galois has accumulated using Haskell commercially for the past 10 years.
You can now read the slides of the talk here:
http://www.galois.com/blog/2009/0
When I try to install Phooey I get the following error:
cabal install --constraint="Stream == 0.3" phooey
Resolving dependencies...
[1 of 1] Compiling Main (
/tmp/phooey-2.016943/phooey-2.0/Setup.lhs,
/tmp/phooey-2.016943/phooey-2.0/dist/setup/Main.o )
Linking /tmp/phooey-2.016943/pho
On Apr 27, 2009, at 18:55 , Vasili I. Galchin wrote:
["-p blastn"] -- CLI args
createProcess expects a list of individual argument strings. You're
sending it a single argument ["-p blastn"]; you want to send it two
arguments ["-p", "blastn"] (or ["-pblastn"] without the spa
I don't have experience solving this problem, but I've read a few
horror stories from people who had state affect the results of parsing
in Parsec.
Haskell's layout rules replace indentation levels with braces and
semicolons; you could run an initial "tokenizing" parser that builds
tokens includin
On Mon, Apr 27, 2009 at 06:00:52PM -0500, Vasili I. Galchin wrote:
> I feel that it has something to do with double quotes in Haskell ...
> probably something obviously silly that I am doing.
The problem is that ["-p blastn"] means that there's only one
argument, while ["-p", "blastn"] means what
Hi Vasili,
Vasili I. Galchin wrote:
> [snip]
>
import System.Process
main = do
handle <- runProcess
"blastall" -- executable
["-p blastn"] -- CLI args
Try:
["-p", "blastn"]
This passes multiple command line arguments instead of just one that
contain
Hello,
I am trying to use createProcess. Following is a small fragment. I am trying
to run a program called blastall (a bio-informatics program). It is kind of
like mv/cp/ln on Unix platforms (where the executable examines the program,
i.e. arg[0], and then provides appropriate behavior/semantics
Quoth siki ,
> The actual problem is quite similar to the one that I provided or to the one
> in the description of the proposed extension that you linked.
>
> Someone on another forum suggested record functions but I'm not sure I
> understood correctly how that would work around this problem. An
Hello,
I am trying to use createProcess. Following is a small fragment. I am trying
to run a program called blastall (a bio-informatics program). It is kind of
like mv/cp/ln on Unix platforms (where the executable examines the program,
i.e. arg[0], and then provides appropriate behavior/semantics
I no longer have the time to continue development of the (apparently,
judging from the number of emails I'm getting, rather popular) graphviz
package. Fortunately, Ivan Lazar Miljenovic who has extended it himself
and sent me patches (some of which I did get round to folding in) has
agreed to take
Basically, I have a bunch of instances that have a common functionality but
I'd like to be able to group those instances and give each group a different
default implementation of that functionality. It's so easy to do this in
Java, for example, but I have no idea how to do it in Haskell. The above
Dear Haskellers,
It is not yet too late to contribute to the May 2009 edition of the
Haskell Communities and Activities Report.
If you haven't already, please write an entry for your new project, or
update your old entry.
Please mail your entries to h...@haskell.org in LaTeX format. More
informa
On Mon, Apr 27, 2009 at 2:41 PM, Bas van Gijzel wrote:
> Hello everyone,
>
> I'm doing a bachelor project focused on comparing parsers. One of the parser
> libraries I'm using is Parsec (2) and I'm going to implement a very small
> subset of haskell with it, with as most important feature the off-
Hello everyone,
I'm doing a bachelor project focused on comparing parsers. One of the parser
libraries I'm using is Parsec (2) and I'm going to implement a very small
subset of haskell with it, with as most important feature the off-side rule
(indentation based parsing) used in function definition
The actual problem is quite similar to the one that I provided or to the one
in the description of the proposed extension that you linked.
Someone on another forum suggested record functions but I'm not sure I
understood correctly how that would work around this problem. Any suggestion
is greatl
No, but functionality similar to this has been proposed several times,
under the name "Class Aliases" [1].
The big problem is in the definition of B:
class (A a) => B a where ...
In this case, you must make something an instance of A before it can
be an instance of B, and, in order to make som
siki wrote:
I'm not sure if this is possible at all. I'd like to do something like this:
class A a where
foo :: a -> Double
foo a = 5.0
class (A a) => B a where
foo a = 7.0
This is currently not possible in Haskell. It's been proposed, though:
http://haskell.org/haskellwik
2009/04/21 Manlio Perillo :
> Luke Palmer ha scritto:
>> And many other permutations, with differing degrees of
>> laziness and parametericity.
>
> As long as you stricly read a string from the socket, this is
> ok. But you can not read a string lazily.
Why not? It changes the way in which the p
I'm not sure if this is possible at all. I'd like to do something like this:
class A a where
foo :: a -> Double
foo a = 5.0
class (A a) => B a where
foo a = 7.0
data Blah = Blah
data Bar = Bar
instance A Blah
instance B Bar
let blah = Blah
bar = Bar
foo blah -- should
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
On Apr 27, 2009, at 12:25 , Thomas Hartman wrote:
One reason it would be nice to be able to do this, is you could then
get lambdabot :src style listings of prelude function definitions by
using the ghci debugger and :list for prelude functions.
I t
Most enlightening, thanks.
The same effect can be seen with Debug.Trace.trace around the two versions of f.
I suppose this means that the points-free/pattern binding-style
version is a bit less work for ghc to execute (fewer reductions),
whereas the version with lambda bound variables is easier t
Tillmann Rendel wrote:
Achim Schneider wrote:
In other words:
1) Explain Pointed
2) Explain Functor
3) Explain Applicative
4) Explain Monad
Why Pointed first? Functor seems more useful and more basic.
They are in order of power: every monad is an applicative; every
applicative is a functor
Achim Schneider wrote:
In other words:
1) Explain Pointed
2) Explain Functor
3) Explain Applicative
4) Explain Monad
Why Pointed first? Functor seems more useful and more basic.
Tillmann
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http:
Matthew Brecknell brecknell.org> writes:
> [...]
> Nest ((,) (l b) (l b)) ~ Nest (l' b')
> l' ~ (,) (l b)
> b' ~ (l b) -- (5)
>
> Unifying (2) and the result type from (3):
>
> n ((,) (z b) (z b)) ~ n (z' b')
> z' ~ (,) (z b)
> b' ~ (z b) -- (6)
>
> >From (5) and
semanticphilosopher:
> Count me in too
>
> I've got a library that endeavours to deliver 'rate-equivalence' - i.e
> there may be some jitter in when the events should have occurred but
> their long term rate of progress is stable.
>
> Testing has shown that I can get events to occur at the righ
semanticphilosopher:
> Count me in too
>
> I've got a library that endeavours to deliver 'rate-equivalence' - i.e
> there may be some jitter in when the events should have occurred but
> their long term rate of progress is stable.
>
> Testing has shown that I can get events to occur at the righ
lane:
>
> Is there any interest or movement in developing thread priority or any
> other realtime support in Haskell?
I think thread priorities would be really cool :)
-- Don
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Am Montag, 27. April 2009 00:11:20 schrieb Duncan Coutts:
> On Sun, 2009-04-26 at 19:03 +0200, Sven Panne wrote:
> [...]
> >* How to link programs using OpenGL
>
> This is because the GL libs are called different names on different
> platforms right? But they're consistent within each platform,
On Mon, Apr 27, 2009 at 02:10:28PM +0100, Duncan Coutts wrote:
> If you're using ghc 6.10 then the solution is to update to cabal-install
> 0.6.x. If you're quite sure you are using 6.8 then the bug is unknown.
> It may still be worth trying upgrading to cabal-install 0.6.x.
I've upgraded to caba
tomahawkins:
> Atom is a DSL in Haskell for designed hard realtime embedded programs.
> At Eaton, we are using it to control hydraulic hybrid refuse trucks
> and shuttle buses. After my talk at CUFP
> (http://cufp.galois.com/2008/schedule.html), a few people inquired
> about atom -- I finally had
One reason it would be nice to be able to do this, is you could then
get lambdabot :src style listings of prelude function definitions by
using the ghci debugger and :list for prelude functions.
is this possible? so far I have tried
thart...@ubuntu:~/haskellInstalls/ghcInstalls/source/ghc-6.10.1/
Michael P Mossey wrote:
> Michael P Mossey wrote:
>> However, I would like some ability to subscribe to specific comments. I
>> want to see if people have replied to me or what the latest discussion is.
>
> Okay, to follow up my own post, I discovered the subscription
> button for each chapter.
On Mon, Apr 27, 2009 at 02:10:28PM +0100, Duncan Coutts wrote:
> > [...]
> > Increasing verbosity does not help, memory consumption goes up after the
> > message "Resolving dependencies..." shows up.
> >
> > I use ghc 6.8.2 and cabal-install version 0.5.1 using version 1.4.0.1 of
> > the Cabal li
Richard O'Keefe wrote:
>
> On 25 Apr 2009, at 8:59 pm, Miguel Mitrofanov wrote:
>
>> Something like
>>
>> newtype MyCoolMonad = MyCoolMonad (FirstTransformer (SecondTransformer
>> (ThirdTransformer Whatever))) deriving (Functor, Monad, FirstClass,
>> SecondClass, ThirdClass, SomeOtherClass)
[...]
On Sun, 2009-04-26 at 21:49 -0700, Daryoush Mehrtash wrote:
>
> When I try to install phooey I get conflict with old-time that I am
> not sure how to resolve. Any ideas?
>
>
> > cabal install phooey
> Resolving dependencies...
> cabal: dependencies conflict: ghc-6.10.1 requires old-time ==1.0.
On Mon, 2009-04-27 at 12:56 +0200, Krzysztof Kościuszkiewicz wrote:
> Hello Haskell-Café,
>
> I have a problem with high memory usage of cabal-install. Whenever I
> try to install or upgrade a package, cabal manages to consume 1,3G of
> memory before I killed it (on a 32-bit machine with 1 GB of
Jakiej platformy dokładnie dotyczy Twój problem?
Proponuję upgrade do najnowszej wersji - można ją ściągnąć ze strony GHC.
Pozdrawiam
Krzysztof Skrzętnicki
2009/4/27 Krzysztof Kościuszkiewicz :
> Hello Haskell-Café,
>
> I have a problem with high memory usage of cabal-install. Whenever I
> try
Hello Haskell-Café,
I have a problem with high memory usage of cabal-install. Whenever I
try to install or upgrade a package, cabal manages to consume 1,3G of
memory before I killed it (on a 32-bit machine with 1 GB of memory).
Increasing verbosity does not help, memory consumption goes up after
Is there a Haskell Wiki page on extensible exceptions? The paper is a fine
reference, it'd be cool to have a wiki page giving programmer-oriented
guidance, saying
what comes with GHC
what other packages are available
and some simple examples of how to use them.
Simon
| -Or
Hi,
Daryoush Mehrtash writes:
> When I try to install phooey I get conflict with old-time that I am not sure
> how to resolve. Any
> ideas?
>
>> cabal install phooey
> Resolving dependencies...
> cabal: dependencies conflict: ghc-6.10.1 requires old-time ==1.0.0.2 however
> old-time-1.0.0.2 wa
Keith Battocchi wrote:
> data Nest a = Nil | Cons(a, (Nest (Pair a)))
> type Pair a = (a,a)
>
> pair f (a,b) = (f a, f b)
>
> efold :: forall n m b.
> (forall a. n a)
> -> (forall a . (m a, n (Pair a)) -> n a)
> -> (forall a. Pair (m a) -> m (Pair a))
> -> (forall l z. (l b -> m (z b))
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