On 2009 Apr 6, at 23:06, FFT wrote:
I remember hearing about a Haskell mode for Vim, Emacs, Yi or
VisualHaskell that inserts type declarations automatically (it's
lazier to just check the type than to write it manually), but I can't
remember any details. What editor mode / IDE was it?
I think
Jason Dagit wrote:
On Mon, Apr 6, 2009 at 10:09 PM, Eugene Kirpichov ekirpic...@gmail.com wrote:
Since the argument to sortBy must impose a linear ordering on its
arguments, and any linear ordering may as well be generated by
assigning an integer to each element of type 'a', and your sorting
On 7 Apr 2009, at 07:37, David Menendez wrote:
On Mon, Apr 6, 2009 at 1:46 PM, Luke Palmer lrpal...@gmail.com
wrote:
On Mon, Apr 6, 2009 at 11:42 AM, David Menendez d...@zednenem.com
wrote:
Of course, this suggests that mfix should be fixM, so perhaps a
better
distinction is that mplus
Is the call to go in the following code considered as tail recursion?
data DList a = DLNode (DList a) a (DList a)
mkDList :: [a] - DList a
mkDList [] = error
http://haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html#v:error
must have at least one element
mkDList xs = let (first,last
I remember hearing about a Haskell mode for Vim, Emacs, Yi or
VisualHaskell that inserts type declarations automatically (it's
lazier to just check the type than to write it manually), but I can't
remember any details. What editor mode / IDE was it?
As far as I know, my haskellmode plugins for
On Tue, 7 Apr 2009, Stephan Friedrichs wrote:
Henning Thielemann wrote:
is there a monad transformer to consume an input list? I've got external
events streaming into the monad that are consumed on demand and I'm
not sure if there's something better than a StateT.
I wondered that, too. I
From: Jeff Heard jefferson.r.he...@gmail.com
Is there a way to do something like autoconf and configure
dependencies at install time? Building buster, I keep adding
dependencies and I'd like to keep that down to a minimum without the
annoyance of littering Hackage with dozens of packages.
I have become aware that many Haskellers are not aware of the
Haskell mode plugins for Vim, in spite of the 100 downloads
per month I saw when I last checked. Since the plugins have just
completed their move to their new home at
http://projects.haskell.org/haskellmode-vim/
this seems to be a
John Lato wrote:
From: Jeff Heard jefferson.r.he...@gmail.com
Is there a way to do something like autoconf and configure
dependencies at install time? Building buster, I keep adding
dependencies and I'd like to keep that down to a minimum without the
annoyance of littering Hackage with dozens
2009/4/6 Marko Schütz markoschu...@web.de:
I have an application where some simple data extracted from some
source files is inserted into a PostgreSQL database. The application
uses Takusen and is compiled with GHC 6.8.3. Some (59 in the test
data) of the selects take on average 460ms each
Hi Claus,
http://projects.haskell.org/haskellmode-vim/
The download link on this page seems to use \ instead of /, making it not
work.
For anyone eager to download it, just replace \ (or %5C) in your address bar
with \ and it should work.
Gr.
Matthijs
signature.asc
Description: Digital
Daryoush Mehrtash wrote:
Is the call to go in the following code considered as tail recursion?
data DList a = DLNode (DList a) a (DList a)
mkDList :: [a] - DList a
mkDList [] = error must have at least one element
mkDList xs = let (first,last) = go last xs first
in first
Matt Morrow:
On Mon, Apr 6, 2009 at 7:39 PM, Manuel M T Chakravarty c...@cse.unsw.edu.au
wrote:
Peter Berry:
3) we apply appl to x, so Memo d1 a = Memo d a. unify d = d1
But for some reason, step 3 fails.
Step 3 is invalid - cf,
Hello.
I am writing a simple game in Haskell as an exercise, and in the
rendering loop I want to cap the framerate to 60fps. I had planned to do
this with GHC.Conc.threadDelay, but looking at it's documentation, I
discovered that it can only delay the thread in time spans that are
multiples of
Hi.
I'm still working on my Netflix Prize project.
For a function I wrote, I really need a data structure that is both
space efficient (unboxed elements) and with an efficient snoc operation.
I have pasted a self contained module with the definition of the
function I'm using:
http://projects.haskell.org/haskellmode-vim/
The download link on this page seems to use \ instead of /, making it not work.
For anyone eager to download it, just replace \ (or %5C) in your address bar
with \ and it should work.
argh, thanks, now fixed (filename completion in Vim, :help
Hi Claus,
I've installed the vimball, and it spit a few errors at me. In particular, it
couldn't find the haddock documentation directory. A quick look at
haskell_doc.vim shows that it should autodetect the directory. However, for
some reason my ghc-pkg command returns the doc directory twice:
Henning Thielemann wrote:
is there a monad transformer to consume an input list? I've got external
events streaming into the monad that are consumed on demand and I'm
not sure if there's something better than a StateT.
I wondered that, too. I wondered whether there is something inverse to
You create one MVar for each task in order to ensure all the tasks are done.
This is pretty heavyweight.
You could create a single Control.Concurrent.QSemN to count the completed tasks,
starting with 0.
Each task is followed by signalQSemN with a value of 1. (I would use
finally).
As
On Mon, Apr 6, 2009 at 7:39 PM, Manuel M T Chakravarty c...@cse.unsw.edu.au
wrote:
Peter Berry:
3) we apply appl to x, so Memo d1 a = Memo d a. unify d = d1
But for some reason, step 3 fails.
Step 3 is invalid - cf,
http://www.haskell.org/pipermail/haskell-cafe/2009-April/059196.html.
Hi,
I've written a parallel_ function, code attached. I'm looking for
criticism, suggestions etc on how to improve the performance and
fairness of this parallel construct. (If it turns out this construct
is already in a library somewhere, I'd be interested in that too!)
The problem I'm trying to
Hello Neil,
Tuesday, April 7, 2009, 2:25:12 PM, you wrote:
The problem I'm trying to solve is running system commands in
parallel.
system commands means execution of external commands or just system
calls inside Haskell?
Running a benchmark of issuing 1 million trivial tasks (create,
I think this is an RTS option.
http://www.haskell.org/ghc/docs/latest/html/users_guide/using-concurrent.html
On Tue, Apr 7, 2009 at 1:41 PM, Ulrik Rasmussen hask...@utr.dk wrote:
Hello.
I am writing a simple game in Haskell as an exercise, and in the
rendering loop I want to cap the
Hello,
is there a monad transformer to consume an input list? I've got external
events streaming into the monad that are consumed on demand and I'm
not sure if there's something better than a StateT.
I wondered that, too. I wondered whether there is something inverse to
Writer, and Reader is
Bulat Ziganshin wrote:
Hello Cristiano,
Sunday, April 5, 2009, 12:05:02 AM, you wrote:
Is it me or the above package is not included in Hoogle?
afair, Neil, being windows user, includes only packages available for
his own system
there was a large thread a few months ago and many
John Lato wrote:
I think that the proper solution is to break up libraries into
separate packages as Jeff suggests (buster, buster-ui, etc.), but then
the total packages on hackage would explode. I don't feel great about
I thought about this a while back and came to the conclusion that the
Hi Matthijs,
I've installed the vimball, and it spit a few errors at me. In particular, it
couldn't find the haddock documentation directory. A quick look at
haskell_doc.vim shows that it should autodetect the directory. However, for
some reason my ghc-pkg command returns the doc directory
Neil Mitchell wrote:
Sorry, accidentally sent before finishing the response! I also noticed
you sent this directly to me, not to -cafe, was that intentional?
The mail/news gateway makes it look like that, but I also sent to the mailing
list.
You mean something like:
parallel_ xs =
sem
Hi Claus,
I've found two more little bugs. The first is that version comparison is
incorrect. It now requires that all components are greater, so comparing
6.10.1 = 6.8.2 returns false (since 1 2).
Also, there is a ghc-pkg field * haddock-html call, but here the * will be
expanded by the shell
On Tue, 2009-04-07 at 14:31 +0100, Neil Mitchell wrote:
Hi
Is it me or the above package is not included in Hoogle?
afair, Neil, being windows user, includes only packages available for
his own system
there was a large thread a few months ago and many peoples voted for
excluding
Basically, type checking proceeds in one of two modes: inferring or
checking. The former is when there is no signature is given; the
latter, if there is a user-supplied signature. GHC can infer
ambiguous signatures, but it cannot check them. This is of course
very confusing and we need
Hi
Is it me or the above package is not included in Hoogle?
afair, Neil, being windows user, includes only packages available for
his own system
there was a large thread a few months ago and many peoples voted for
excluding any OS-specific packages at all since this decreases
portability
On Tue, Apr 7, 2009 at 3:31 PM, Neil Mitchell ndmitch...@gmail.com wrote:
I was implementing full package support last weekend. With any luck,
I'll manage to push the changes tonight. If not, I'll push them as
soon as I get back from holiday (a week or so)
Thank you, Neil.
Cristiano
Matthijs,
thanks for the reports, and analyses and suggested patches are even
better! We should probably take this offlist at some point, though.
I've found two more little bugs. The first is that version comparison is
incorrect. It now requires that all components are greater, so comparing
This has been a lot on my mind lately as my current library provides
additional functionality to data types from a wide array of other packages.
I face a version of Wadler's expression problem.
I provide a set of classes for injecting into monoids/seminearrings/etc. to
allow for quick reductions
Hi
The problem I'm trying to solve is running system commands in
parallel.
system commands means execution of external commands or just system
calls inside Haskell?
Calls to System.Cmd.system, i.e. running external console processes.
It's a make system I'm writing, so virtually all the
On Tue, Apr 07, 2009 at 04:01:01PM +0200, Peter Verswyvelen wrote:
Are you on Windows? Because this might be because GHC is not using a high
resolution timer for doing its scheduling, I don't know...
No, Ubuntu 8.10. That may very well be, I'm not that much into the
details of GHC.
I'm
Do you want to cap the rendering framerate at 60FPS or the animation
framerate?
Because when you use OpenGL and GLFW, you can just
GLFW.swapInterval $= 1
to cap the rendering framerate at the refresh rate of your monitor or LCD
screen (usually 60Hz)
On Tue, Apr 7, 2009 at 1:41 PM, Ulrik
I'm in the process of adding a Data.Sequence.Unboxed to unboxed-containers.
I hope to have it in hackage today or tomorrow, should its performance work
out as well as Data.Set.Unboxed.
Be warned the API will likely be shifting on you for a little while, while I
figure out a better way to manage
| Here is a variation to make this point clearer:
|
| {-# LANGUAGE NoMonomorphismRestriction #-}
| {-# LANGUAGE TypeFamilies, ScopedTypeVariables #-}
|
| class Fun d where
| type Memo d :: * - *
| abst :: (d - a) - Memo d a
| appl :: Memo d a - (d - a)
|
| f = abst . appl
|
| -- f' ::
OPEN CALL FOR PAPERS
JFP Special Issue on Generic Programming
Deadline: 1 October 2009
http://www.comlab.ox.ac.uk/ralf.hinze/JFP/cfp.html
Scope
-
Generic programming is about making programs more
Hello Neil,
Tuesday, April 7, 2009, 6:13:29 PM, you wrote:
Calls to System.Cmd.system, i.e. running external console processes.
It's a make system I'm writing, so virtually all the time is spent in
calls to ghc etc.
To Bulat: I should have been clearer with the spec. The idea is that
On 07/04/2009, Ryan Ingram ryani.s...@gmail.com wrote:
On Mon, Apr 6, 2009 at 2:36 PM, Peter Berry pwbe...@gmail.com wrote:
As I understand it, the type checker's thought process should be along
these lines:
1) the type signature dictates that x has type Memo d a.
2) appl has type Memo d1 a
| Here is a variation to make this point clearer:
|
| {-# LANGUAGE NoMonomorphismRestriction #-}
| {-# LANGUAGE TypeFamilies, ScopedTypeVariables #-}
|
| class Fun d where
| type Memo d :: * - *
| abst :: (d - a) - Memo d a
| appl :: Memo d a - (d - a)
|
| f = abst . appl
|
| -- f' ::
Hello Bulat,
Tuesday, April 7, 2009, 6:50:14 PM, you wrote:
tid - forkIO (executing commands from chan...)
waitQSem sem
killThread tid
instead of killThread we really should send pseudo-job (like my
Nothing value) that will led to self-killing of job that gets this
signal
this
Neil Mitchell wrote:
I guess the nested calls to parallel_ bit is the part of the spec
that makes everything much harder!
Thanks
Neil
Yes. Much more annoying.
But the problem here is generic. To avoid it you must never allow all thread to
block at once.
The parallel_ function is
This is a random idea, that's probably not going to work, but I don't have a
way of testing it so I'll just post it!
How about using unsafeInterleaveIO to get a lazy suspension of the result of
each action, and then using par to spark off each of them? If that works you
can reuse the existing
Edward Kmett ha scritto:
I'm in the process of adding a Data.Sequence.Unboxed to
unboxed-containers. I hope to have it in hackage today or tomorrow,
should its performance work out as well as Data.Set.Unboxed.
Looking at the data definition of Data.Sequence I suspect that it is not
really
On Mon, Apr 6, 2009 at 7:39 PM, Manuel M T Chakravarty
c...@cse.unsw.edu.au wrote:
Peter Berry:
3) we apply appl to x, so Memo d1 a = Memo d a. unify d = d1
But for some reason, step 3 fails.
Step 3 is invalid - cf,
http://www.haskell.org/pipermail/haskell-cafe/2009-April/059196.html.
Hello Neil,
Tuesday, April 7, 2009, 6:13:29 PM, you wrote:
Consider a thread pool with 2 threads and the call parallel_ [parallel_
[b,c],a]
You get the sequence:
enqueue (parallel_ [b,c])
a
wait on parallel_ [b,c]
While you are executing a, a thread pool starts:
enqueue b
c
wait for
On Tue, Apr 07, 2009 at 04:34:22PM +0200, Peter Verswyvelen wrote:
Do you want to cap the rendering framerate at 60FPS or the animation
framerate?
Because when you use OpenGL and GLFW, you can just
GLFW.swapInterval $= 1
to cap the rendering framerate at the refresh rate of your monitor
Hi
Sebastian:
How about using unsafeInterleaveIO to get a lazy suspension of the result of
each action,
and then using par to spark off each of them? If that works you can reuse
the existing
task-parallel system of GHC to do the heavily lifting for you, instead of
having to write your
Hello Neil,
Tuesday, April 7, 2009, 6:13:29 PM, you wrote:
Calls to System.Cmd.system, i.e. running external console processes.
It's a make system I'm writing, so virtually all the time is spent in
calls to ghc etc.
btw, if all that you need is to limit amount of simultaneous
Hi Bulat,
btw, if all that you need is to limit amount of simultaneous
System.Cmd.system calls, you may go from opposite side: wrap this call
into semaphore:
sem = unsafePerformIO$ newQSem numCapabilities
mysystem = bracket_ (waitQSem sem) (signalQSem sem) . system
and implement para as
Hello Neil,
Tuesday, April 7, 2009, 7:33:25 PM, you wrote:
How about using unsafeInterleaveIO to get a lazy suspension of the result of
each action,
and then using par to spark off each of them? If that works you can reuse
the existing
task-parallel system of GHC to do the heavily lifting
Hello Neil,
Tuesday, April 7, 2009, 7:33:25 PM, you wrote:
parallel_ (x1:xs) = do
sem - newQSem $ 1 - length xs
forM_ xs $ \x -
writeChan queue (x signalQSem sem, False)
x1
addWorker
waitQSem sem
writeChan queue (signalQSem sem, True)
waitQSem sem
Hello Neil,
Tuesday, April 7, 2009, 7:47:17 PM, you wrote:
para = mapM_ forkIO
I might try that tomorrow and see if it makes a difference to the
performance. While the majority of computation is in system calls,
quite a few of the threads open files etc, and having them all run in
parallel
The Hipmunk 2D physics engine comes with a playground app which
includes the following function:
-- | Advances the time.
advanceTime :: IORef State - Double - KeyButtonState - IO Double
advanceTime stateVar oldTime slowKey = do
newTime - get time
-- Advance simulation
let slower = if
Hello Bulat,
Tuesday, April 7, 2009, 7:50:08 PM, you wrote:
parallel_ (x1:xs) = do
sem - newQSem $ 1 - length xs
forM_ xs $ \x -
writeChan queue (x signalQSem sem, False)
x1
addWorker
waitQSem sem
writeChan queue (signalQSem sem, True)
waitQSem sem
Hi
par is likely to spark all the computations, and then switch between
them - which will mean I've got more than N things running in
parallel.
| par/GHC RTS limits amount of Haskell threads running simultaneously.
| with a system call marked as safe, Capability will be freed while we
|
yes get time comes from GLFW; that is get comes from OpenGL, time from
GLFW.
I think the time provided by GLFW has a very high resolution but is not very
accurate in the long run, which is not a real problem for games I guess
On Tue, Apr 7, 2009 at 6:09 PM, Duane Johnson
Hello Bulat,
Tuesday, April 7, 2009, 8:10:43 PM, you wrote:
parallel_ (x1:xs) = do
sem - newQSem $ 1 - length xs
forM_ xs $ \x -
writeChan queue (x signalQSem sem, False)
x1
addWorker
waitQSem sem
writeChan queue (signalQSem sem, True)
waitQSem sem
Edward,
Thanks for straightening me out; I see the problems better now. In
particular I was missing:
1) Orphaned types (and related design issues) get in the way of
splitting the package.
2) Viral dependencies work in two directions, since upstream packages
must pick up your deps to
I'm facing this problem too, with hledger. It has optional happstack and
vty interfaces which add to the difficulty and platform-specificity of
installation. Currently I publish all in one package with a cabal flag
for each interface, with happstack off and vty on by default. vty isn't
My solution is this transformer:
newtype ConsumerT c m a
= ConsumerT { runConsumerT :: [c] - m (a, [c]) }
instance (Monad m) = Monad (ConsumerT c m) where
return x = ConsumerT $ \cs - return (x, cs)
m = f = ConsumerT $ \cs - do
~(x, cs') - runConsumerT m cs
On Tue, 7 Apr 2009, Stephan Friedrichs wrote:
My solution is this transformer:
newtype ConsumerT c m a
= ConsumerT { runConsumerT :: [c] - m (a, [c]) }
instance (Monad m) = Monad (ConsumerT c m) where
return x = ConsumerT $ \cs - return (x, cs)
m = f = ConsumerT $ \cs - do
The problem of type class instances for third-party types is exactly
how I ran into this. Currently I don't know of a good solution, where
good means that it meets these criteria:
1. Does not introduce orphan instances
2. Allows for instances to be provided based upon the user's
installed
split n [] = []
split n xs = take n xs : split n (drop n xs)
main = do
text - readFile source
mapM_ (\(n,dat) - writeFile (dest ++ show n) dat) . zip [0..] . split
1 . lines $ text
Modulo brainos... but you get the idea. This is lazy (because readFile is).
Luke
On Tue, Apr 7, 2009
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