Re: [Haskell-cafe] sendfile leaking descriptors on Linux?
As far as I can tell, stepcut was probably correct in his diagnosis before. I was getting two processes started because of a stray cron job. 2010/2/26 Thomas Hartman tphya...@gmail.com: Indeed, the error occurs when two processes are running at the same time. One process isn't serving anything, and the other is just looping, reported that it can't stop because the port is taken, and repeating ad infinitum. The loop I have is ulimit -v 15 while true; do echo starting patchtag: `date` ./dist/build/patchtagserver/patchtagserver --port=80 -- echo patchtag exited: `date` echo patchtag exited: `date` patch-tag.log rm -f _local/patchtagserver_state.lock The ulimit is so that it will die after consuming a reasonable amount of memory. (I seem to have a memory leak somewhere, but it takes many hours to get up to 150M.) Everything else looks pretty standard to me. It seems to work as designed most of the time, but occasionally will result in two processes. I'm baffled as to how this happens. If anybody has any idea, I would love to hear them. 2010/2/26 Jeremy Shaw jer...@n-heptane.com: Hello, It will be interesting to see if that makes any difference -- it shouldn't. In happstack-server we use 'listenOn'. According to the documentation listenOn already sets ReuseAddr: http://hackage.haskell.org/packages/archive/network/2.2.1.7/doc/html/Network.html#v%3AlistenOn A quick look at the source code confirms it is calling: setSocketOption sock ReuseAddr 1 It sounds to be like you are getting the socket in use error because you have 2 processes running. Seems like the first one hasn't really died, but the second one is started anyway. How is it that your loop starts a second server when the first one has not finished? - jeremy On Fri, Feb 26, 2010 at 1:43 PM, Thomas Hartman tphya...@gmail.com wrote: Thanks, I altered my top level request handler as follows mysmartserver conf h stateProxy = do socket - bindPort conf I added (setSocketOption socket ReuseAddr 1) here Should this be added in a comment, or even in function code, in Happstack.Server.SimpleHTTP? What are the tradeoffs, when would you *not* want ot use ReuseAddr?) webserverTid - forkIO $ simpleHTTPWithSocket socket conf h putStrLn . ( starting happs server ++ ) = time control - startSystemState stateProxy -- start the HAppS state system putStrLn . ( happs state started ++ ) = time waitForTermination killThread webserverTid stateShutdown control I can't replicate the error reliably so I won't know if it actually fixed the problem for a while, therefore just leaving this cookie crumb trail in case others may find it helpful. 2010/2/26 Brandon S. Allbery KF8NH allb...@ece.cmu.edu: On Feb 26, 2010, at 04:28 , Thomas Hartman wrote: me: Like mightybyte, I run my app in a shell loop that will just restart it after a crash. But every once in a while it won't restart because of the busy socket and I need to do a manual restart, killing multiple processes (usually 2). the error I get is: bind: resource busy (Address already in use) This is on application restart? It's not out of file descriptors, it's just the system keeping the socket around (netstat will show it in TIME_WAIT, or possibly in a shutdown negotiation state such as LAST_ACK, FIN_WAIT, etc. TCP lacks *reliable* socket shutdown negotiation). You want to configure the socket with SO_REUSEADDR before trying to bind it (setSocketOption socket ReuseAddr 1). As to the portable version of sendfile, it's because not all systems offer a sendfile() system call. Linux and *BSD do, and can use the native implementation; the portable version emulates sendfile() when it doesn't exist, at the price of additional CPU usage/system load (sendfile() having been created specifically to reduce system load in the common case for web servers). -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Real-time garbage collection for Haskell
Did you really seen 100ms pauses?! I never did extensive research on this but my numbers are rather in microseconds range (below 1ms). What causes such a long garbage collection? Lots of allocated and long-living objects? Pavel. On 28.02.2010, at 8:20, Luke Palmer wrote: I have seen some proposals around here for SoC projects and other things to try to improve the latency of GHC's garbage collector. I'm currently developing a game in Haskell, and even 100ms pauses are unacceptable for a real-time game. I'm calling out to people who have seen or made such proposals, because I would be willing to contribute funding and/or mentor a project that would contribute to this goal. Also any ideas for reducing this latency in other ways would be very appreciated. Thanks, Luke ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Real-time garbage collection for Haskell
My experience agrees with Pavel. I've never observed ones that size. I have an application that runs in 'rate equivalent real-time' (i.e. there may be some jitter in the exact time of events but it does not accumulate). It does have some visibility of likely time of future events and uses that to perform some speculative garbage collection. GC is pretty short and i've not seen an effect 1ms in those runs (all the usual caveats apply - my programs are not your programs etc). Neil On 28 Feb 2010, at 09:06, Pavel Perikov wrote: Did you really seen 100ms pauses?! I never did extensive research on this but my numbers are rather in microseconds range (below 1ms). What causes such a long garbage collection? Lots of allocated and long-living objects? Pavel. On 28.02.2010, at 8:20, Luke Palmer wrote: I have seen some proposals around here for SoC projects and other things to try to improve the latency of GHC's garbage collector. I'm currently developing a game in Haskell, and even 100ms pauses are unacceptable for a real-time game. I'm calling out to people who have seen or made such proposals, because I would be willing to contribute funding and/or mentor a project that would contribute to this goal. Also any ideas for reducing this latency in other ways would be very appreciated. Thanks, Luke ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] listing mountpoints and getting their properties in Haskell
On Sat, Feb 27, 2010 at 06:27:19PM -0500, Brandon S. Allbery KF8NH wrote: I don't know of any Haskell bindings offhand, but getmntent() and friends are the standard library interface for identifying mountpoints and statfs()/statvfs() are the interface for getting information about them. Be aware that the latter can be fairly system-dependent. getmntent() isn't in any standard I know about. IMHO, getting information about mounted filesystems will always be system dependent. Ciao, Kili ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Real-time garbage collection for Haskell
Luke Palmer wrote: I have seen some proposals around here for SoC projects and other things to try to improve the latency of GHC's garbage collector. I'm guessing making the GC concurrent (i.e., so you can perform GC without having to stop all Haskell threads) would probably help in the multithreaded case... (I'm also guessing this is slightly nontrivial to implement. :-) ) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Haskell version of Monad Transformers and Modular Interpreters
Hello, I come across the paper Monad Transformers and Modular Interpreters (http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.17.268) alas the code is in Gofer and I'm not certain how all of it translates to Haskell. Are there other papers out there that translate this to Haskell? Günther ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell version of Monad Transformers and Modular Interpreters
Hi Günther Wolfram Kahl has a tech report 'A Modular Interpreter Built with Monad Transformers' with a Haskell translation. http://www.cas.mcmaster.ca/~kahl/FP/2003/Interpreter.pdf Best wishes Stephen 2010/2/28 Günther Schmidt gue.schm...@web.de: Hello, I come across the paper Monad Transformers and Modular Interpreters (http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.17.268) alas the code is in Gofer and I'm not certain how all of it translates to Haskell. Are there other papers out there that translate this to Haskell? Günther ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] OpenSUSE 11.2
Daniel Fischer wrote: Am Mittwoch 24 Februar 2010 23:17:46 schrieb Andrew Coppin: Erlend Hamberg wrote: if you open the software manager and go to configuration → repositories, you should be able to add new software sources. i use the following repository: Server name: download.opensuse.org Directory: /repositories/devel:/languages:/haskell/openSUSE_11.2/ This repository contains GHC 6.12, alex, happy, etc. OK, I'll try that tomorrow and see where I get... Or, go to http://software.opensuse.org/search/ , type ghc [alex, happy, ...] in the search box, click the search button and 1-click-install. This works - and adds all the Haskell stuff to the respositories list, apparently. Amusingly, I installed the GHC package, and then discovered that while GHC runs, it won't compile anything. But if you (manually) install GCC as well, *then* it works. (Isn't that the package manager's job? WTF?) Anyway, I'm currently attempting to get cabal-install to work... ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: native threads vs. -threaded
Donn Cave d...@avvanta.com wrote: I imagine I'm at fault somewhere in this, since I am also responsible for the GHC port to Haiku, but just wondering if this suggests an obvious course of inquiry to anyone. I assume it's not working as intended, as from the documentation I would rather have guessed that -thread would be required in this situation. Could it be that Haiku is expecting BeOS threads but you give it UNIX processes? It might be that all threads serving a GUI app must be part of the same team. -- (c) this sig last receiving data processing entity. Inspect headers for copyright history. All rights reserved. Copying, hiring, renting, performance and/or quoting of this signature prohibited. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] OpenSUSE 11.2
Am Sonntag 28 Februar 2010 13:23:11 schrieb Andrew Coppin: Daniel Fischer wrote: Or, go to http://software.opensuse.org/search/ , type ghc [alex, happy, ...] in the search box, click the search button and 1-click-install. This works - and adds all the Haskell stuff to the respositories list, apparently. Amusingly, I installed the GHC package, and then discovered that while GHC runs, it won't compile anything. But if you (manually) install GCC as well, *then* it works. (Isn't that the package manager's job? WTF?) Wait, what? That must be the first Linux in history which didn't have gcc installed from the beginning. How on earth did you manage to do that? Another thing, you will want the devel versions of many packages for the header files, so start YaST, search for devel in name, install all you are not almost sure that you don't want. Anyway, I'm currently attempting to get cabal-install to work... What's the problem? Downloading the .tar.gz from hackage, unpacking it and running bootstrap.sh *should* get you a working cabal-install with minimum fuss. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] listing mountpoints and getting their properties in Haskell
On Feb 28, 2010, at 05:17 , Matthias Kilian wrote: On Sat, Feb 27, 2010 at 06:27:19PM -0500, Brandon S. Allbery KF8NH wrote: I don't know of any Haskell bindings offhand, but getmntent() and friends are the standard library interface for identifying mountpoints and statfs()/statvfs() are the interface for getting information about them. Be aware that the latter can be fairly system-dependent. getmntent() isn't in any standard I know about. IMHO, getting information about mounted filesystems will always be system dependent. It's more of a de-facto standard, inherited from System V but not part of SVID and successors. Between Linux/glibc and Solaris you have a goodly chunk of the GHC-relevant world. *BSD and Mac OS X should look at getmntinfo(); I suspect that'll be painful to get at via the FFI, though. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon universityKF8NH PGP.sig Description: This is a digitally signed message part ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Cabal will not find HaXml
Hi When I do: cabal list --simple-output | grep -i HaXml 1.20 I get: HaXml 1.20 HaXml 1.20.1 HaXml 1.20.2 But when running: runhaskell Setup.hs configure I get: Configuring XrcAccessors-0.0... Setup.hs: At least the following dependencies are missing: HaXml -any My cabal file looks like: snip Executable XrcAccessors Main-is: XrcAccessors.hs Build-Depends: base==3.0.*, pretty==1.0.*, HaXml hs-source-dirs:src /snip This is very confusing to me. Why will Cabal not find HaXml when running Setup.hs, but do find it when running cabal list ? My Setup.hs looks like: import Distribution.Simple main = defaultMain I have tried reinstalling HaXml, but that do not help. I have noticed one thing though, when doing: ghc-pkg I get output like: snip /home/ghc6103/lib/ghc-6.10.3/./package.conf: Cabal-1.6.0.3, HUnit-1.2.0.3, QuickCheck-1.2.0.0, array-0.2.0.0, base-3.0.3.1, base-4.1.0.0, bytestring-0.9.1.4, containers-0.2.0.1, directory-1.0.0.3, (dph-base-0.3), (dph-par-0.3), /snip snip /home/ghc6103/.ghc/x86_64-linux-6.10.3/package.conf: Cabal-1.6.0.2, Cabal-1.8.0.2, Diff-0.1.2, HDBC-2.1.1, HDBC-odbc-1.1.6.0, HDBC-odbc-2.1.0.0, HTTP-4000.0.4, HUnit-1.2.2.1, HaXml-1.20.2, MetaHDBC-0.1.0, QuickCheck-2.1.0.3, SQLLib-0.0, /snip That is, HaXml shows itself in the /home/ghc6103/.ghc/x86_64-linux-6.10.3/package.conf list, but not in the /home/ghc6103/.ghc/x86_64-linux-6.10.3/package.conf . Is this the problem and how do I fix it? Greetings, Mads Lindstrøm signature.asc Description: This is a digitally signed message part ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal will not find HaXml
Am Sonntag 28 Februar 2010 14:41:03 schrieb Mads Lindstrøm: Hi When I do: cabal list --simple-output | grep -i HaXml 1.20 I get: HaXml 1.20 HaXml 1.20.1 HaXml 1.20.2 So there are versions HaXml 1.20* available on hackage But when running: runhaskell Setup.hs configure For that, you must have one installed already, and unless you pass the -- user flag, that must be in the global package database. I get: Configuring XrcAccessors-0.0... Setup.hs: At least the following dependencies are missing: HaXml -any ghc-pkg I get output like: snip /home/ghc6103/lib/ghc-6.10.3/./package.conf: Cabal-1.6.0.3, HUnit-1.2.0.3, QuickCheck-1.2.0.0, array-0.2.0.0, base-3.0.3.1, base-4.1.0.0, bytestring-0.9.1.4, containers-0.2.0.1, directory-1.0.0.3, (dph-base-0.3), (dph-par-0.3), /snip global package database, no HaXml snip /home/ghc6103/.ghc/x86_64-linux-6.10.3/package.conf: Cabal-1.6.0.2, Cabal-1.8.0.2, Diff-0.1.2, HDBC-2.1.1, HDBC-odbc-1.1.6.0, HDBC-odbc-2.1.0.0, HTTP-4000.0.4, HUnit-1.2.2.1, HaXml-1.20.2, MetaHDBC-0.1.0, QuickCheck-2.1.0.3, SQLLib-0.0, /snip user package database, HaXml present That is, HaXml shows itself in the /home/ghc6103/.ghc/x86_64-linux-6.10.3/package.conf list, but not in the /home/ghc6103/.ghc/x86_64-linux-6.10.3/package.conf . Is this the problem Yes. and how do I fix it? a) cabal install XrcAccessors, in contrast to the runghc ./setup.hs ... route, cabal install's default is user installs b) pass the --user flag to runghc ./Setup.hs configure c) (not recommended in general) make a global install of HaXml, either by runghc ./Setup... or cabal install --global HaXml Greetings, Mads Lindstrøm ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Lists of Existential DT
Hello! I have a class Drawable, and some datatypes which are instances of it, and I would like to be able to draw them all at once! drawMany window [image, text, otherImage] I think the type of the function drawMany would be: drawMany :: Window - [forall a. (Drawable a) = a] - IO () However it doesn't work. I know one solution is to make a new datatype (e.g. DrawableObj) which will be: data DrawableObj = forall a (Drawable a) = DrawableObj a And then declare drawMany as: drawMany :: Window - [DrawableObj] - IO () But to use it I have to wrap up myself every drawable in a DrawableObj: drawMany window [DrawableObj image, DrawableObj text, DrawableObj otherImage] Is there another more suitable way to handle a list of drawables? - Yves Parès Live long and prosper -- View this message in context: http://old.nabble.com/Lists-of-Existential-DT-tp27735354p27735354.html Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal will not find HaXml
Hi The --user flag did the trick. Thank you very much. /Mads Daniel Fischer wrote: Am Sonntag 28 Februar 2010 14:41:03 schrieb Mads Lindstrøm: Hi When I do: cabal list --simple-output | grep -i HaXml 1.20 I get: HaXml 1.20 HaXml 1.20.1 HaXml 1.20.2 So there are versions HaXml 1.20* available on hackage But when running: runhaskell Setup.hs configure For that, you must have one installed already, and unless you pass the -- user flag, that must be in the global package database. I get: Configuring XrcAccessors-0.0... Setup.hs: At least the following dependencies are missing: HaXml -any ghc-pkg I get output like: snip /home/ghc6103/lib/ghc-6.10.3/./package.conf: Cabal-1.6.0.3, HUnit-1.2.0.3, QuickCheck-1.2.0.0, array-0.2.0.0, base-3.0.3.1, base-4.1.0.0, bytestring-0.9.1.4, containers-0.2.0.1, directory-1.0.0.3, (dph-base-0.3), (dph-par-0.3), /snip global package database, no HaXml snip /home/ghc6103/.ghc/x86_64-linux-6.10.3/package.conf: Cabal-1.6.0.2, Cabal-1.8.0.2, Diff-0.1.2, HDBC-2.1.1, HDBC-odbc-1.1.6.0, HDBC-odbc-2.1.0.0, HTTP-4000.0.4, HUnit-1.2.2.1, HaXml-1.20.2, MetaHDBC-0.1.0, QuickCheck-2.1.0.3, SQLLib-0.0, /snip user package database, HaXml present That is, HaXml shows itself in the /home/ghc6103/.ghc/x86_64-linux-6.10.3/package.conf list, but not in the /home/ghc6103/.ghc/x86_64-linux-6.10.3/package.conf . Is this the problem Yes. and how do I fix it? a) cabal install XrcAccessors, in contrast to the runghc ./setup.hs ... route, cabal install's default is user installs b) pass the --user flag to runghc ./Setup.hs configure c) (not recommended in general) make a global install of HaXml, either by runghc ./Setup... or cabal install --global HaXml Greetings, Mads Lindstrøm signature.asc Description: This is a digitally signed message part ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Lists of Existential DT
Sorry, no luck with that. But you can, probably, define some customized comma: data DrawPair a b = DrawPair a b (,) :: a - b - DrawPair a b (,) = DrawPair instance (Drawable a, Drawable b) = Drawable (DrawPair a b) where ... drawMany :: Drawable a = Window - a - IO () ... drawMany window $ image , text , otherImage On 28 Feb 2010, at 17:31, Yves Parès wrote: Hello! I have a class Drawable, and some datatypes which are instances of it, and I would like to be able to draw them all at once! drawMany window [image, text, otherImage] I think the type of the function drawMany would be: drawMany :: Window - [forall a. (Drawable a) = a] - IO () However it doesn't work. I know one solution is to make a new datatype (e.g. DrawableObj) which will be: data DrawableObj = forall a (Drawable a) = DrawableObj a And then declare drawMany as: drawMany :: Window - [DrawableObj] - IO () But to use it I have to wrap up myself every drawable in a DrawableObj: drawMany window [DrawableObj image, DrawableObj text, DrawableObj otherImage] Is there another more suitable way to handle a list of drawables? - Yves Parès Live long and prosper -- View this message in context: http://old.nabble.com/Lists-of-Existential-DT-tp27735354p27735354.html Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Real-time garbage collection for Haskell
Luke Palmer wrote: I have seen some proposals around here for SoC projects and other things to try to improve the latency of GHC's garbage collector. I'm currently developing a game in Haskell, and even 100ms pauses are unacceptable for a real-time game. I'm calling out to people who have seen or made such proposals, because I would be willing to contribute funding and/or mentor a project that would contribute to this goal. Also any ideas for reducing this latency in other ways would be very appreciated. Overly long garbage collection might also be a sign of space leaks. But there are many other things that can go wrong in a real time system and might explain your delays. For example, you might need to avoid amortized time data structures like Data.Sequence . Or for physics simulations, you'd need to fix the time step ∆t, as described in http://gafferongames.com/game-physics/fix-your-timestep/ or numerical integration will deteriorate rather quickly. Regards, Heinrich Apfelmus -- http://apfelmus.nfshost.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: native threads vs. -threaded
Quoth Achim Schneider bars...@web.de,
Donn Cave d...@avvanta.com wrote:
I imagine I'm at fault somewhere in this, since I am also responsible
for the GHC port to Haiku, but just wondering if this suggests an
obvious course of inquiry to anyone. I assume it's not working as
intended, as from the documentation I would rather have guessed that
-thread would be required in this situation.
Could it be that Haiku is expecting BeOS threads but you give it UNIX
processes? It might be that all threads serving a GUI app must be part
of the same team.
No, I'm not creating any other threads or processes, other than the
window thread that's implicitly created by the window API. If it
helps, a coarse outline of the API:
class W : public BWindow {
W(...params...): BWindow(...params...) {
... initialize graphic elements
}
void MessageReceived(BMessage *msg) {
... respond to event by calling Haskell function
// will lead to thread abort if linked -threaded.
}
};
main thread:
W *w = W(...params...);
w-Show(); // thread spawned by this member function.
I haven't written any code to support the above - BWindow::Show()
was provided by the platform. I did of course have to do a lot
of hacking around with FFI stuff. The BWindow-derived object
stores a table of foreign wrapper pointers to callback functions
that take a StablePtr, etc., and I wouldn't know where to start
thinking about that works with garbage collection.
Donn Cave, d...@avvanta.com
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Re: [Haskell-cafe] OpenSUSE 11.2
Daniel Fischer wrote: Am Sonntag 28 Februar 2010 13:23:11 schrieb Andrew Coppin: Amusingly, I installed the GHC package, and then discovered that while GHC runs, it won't compile anything. But if you (manually) install GCC as well, *then* it works. (Isn't that the package manager's job? WTF?) Wait, what? That must be the first Linux in history which didn't have gcc installed from the beginning. How on earth did you manage to do that? It's the default install of OpenSUSE 11.2. Nothing special there. What *does* surprise me is that GCC isn't a dependency of the GHC package, given that GHC doesn't appear to work properly without it. Anyway, I'm currently attempting to get cabal-install to work... What's the problem? Downloading the .tar.gz from hackage, unpacking it and running bootstrap.sh *should* get you a working cabal-install with minimum fuss. No problem, I just haven't finished it yet. Or at least, I hadn't when I posted that message; I've got it going now. Once GHC was actually working, the only additional thing I had to do was install zlib-devel. It also puts the binary in a strange place, but I guess I can live with that... Now, hypothetically, I should have a Linux Haskell system, so I can actually compile *anything* that's on Hackage. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] using haskell to serve with apache
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 hi i'm currently doing some work on a personal site and was considering giving a haskell web tool a spin. i have a fairly complex apache configuration, so i don't want to try to replace it with a native haskell server, but instead use haskell via an interface to apache (i.e. something like wsgi, plack, etc). some searching shows hyena and yesod in various states of development, but i can't figure out if they are appropriate or ready for use. anyone have experiences using haskell behind apache? should i just try out something based on fastcgi? any anecdotes welcome thanks brad -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.10 (FreeBSD) iEYEARECAAYFAkuKoJEACgkQxRg3RkRK91PVJwCdFD4dS47KjJuMcNVZmPkYXKyU ItsAnRoYBE39XtXyXDluh+pHSxzP+Qcd =91Ql -END PGP SIGNATURE- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] OpenSUSE 11.2
Am Sonntag 28 Februar 2010 17:52:19 schrieb Andrew Coppin:
It also puts the binary in a strange place, but I guess I can live with
that...
Which strange place? By default, it should go to ~/.cabal/bin, I think.
Anyway, you should add that to your path, put something like
if [ -z `/bin/echo ${PATH} | /usr/bin/grep cabal` ]
then
export PATH=/home/andrew/.cabal/bin:$PATH
fi
in your .bashrc
Now, hypothetically, I should have a Linux Haskell system, so I can
actually compile *anything* that's on Hackage.
Not really, you'll need to install external libraries (C stuff, mostly) for
many packages. But it should be a lot easier than on Windows.
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Re: [Haskell-cafe] OpenSUSE 11.2
Daniel Fischer wrote:
Am Sonntag 28 Februar 2010 17:52:19 schrieb Andrew Coppin:
It also puts the binary in a strange place, but I guess I can live with
that...
Which strange place? By default, it should go to ~/.cabal/bin, I think.
Indeed. You'd expect it to be in some system-wide location, but
apparently not.
Anyway, you should add that to your path, put something like
if [ -z `/bin/echo ${PATH} | /usr/bin/grep cabal` ]
then
export PATH=/home/andrew/.cabal/bin:$PATH
fi
in your .bashrc
Uh... what?
Now, hypothetically, I should have a Linux Haskell system, so I can
actually compile *anything* that's on Hackage.
Not really, you'll need to install external libraries (C stuff, mostly) for
many packages. But it should be a lot easier than on Windows.
On Linux, it seems you install the development package, rerun Cabal, and
it it somehow knows that the library is installed and how to find in.
On Windows... well, forget it. It'll never work, so you might as well
not bother trying.
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Re: [Haskell-cafe] OpenSUSE 11.2
On Sun, Feb 28, 2010 at 6:30 PM, Andrew Coppin
andrewcop...@btinternet.comwrote:
Daniel Fischer wrote:
if [ -z `/bin/echo ${PATH} | /usr/bin/grep cabal` ]
then
export PATH=/home/andrew/.cabal/bin:$PATH
fi
in your .bashrc
Uh... what?
that snippet supposes you have cabal installed in your home directory under
the directory .cabal. The binary file would be in the bin subdirectory of
.cabal
Names that start with a . are hidden files/directories on linux, by the way.
So the first line checks if you have cabal in your path list. If not, on
the 3rd line it supposes your home directory is /home/andrew and adds the
cabal binary directory to your path list.
David.
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Re: [Haskell-cafe] OpenSUSE 11.2
Am Sonntag 28 Februar 2010 18:30:59 schrieb Andrew Coppin:
Daniel Fischer wrote:
Am Sonntag 28 Februar 2010 17:52:19 schrieb Andrew Coppin:
It also puts the binary in a strange place, but I guess I can live
with that...
Which strange place? By default, it should go to ~/.cabal/bin, I
think.
Indeed. You'd expect it to be in some system-wide location, but
apparently not.
Why? It could only be in a system-wide location if you installed as root.
Not everybody who wants to install cabal is root/can sudo, so the natural
default is ~/.cabal/bin or ~/bin. Since there are advantages to keep all
cabal stuff in one place separate from whatever, ~/.cabal is preferable.
But if you want to have it system-wide (why would you, with a user cabal,
you don't have to make a complete reinstall if you bork your installation),
you can run
$ ./bootstrap.sh --global
Anyway, you should add that to your path, put something like
if [ -z `/bin/echo ${PATH} | /usr/bin/grep cabal` ]
then
export PATH=/home/andrew/.cabal/bin:$PATH
fi
in your .bashrc
Uh... what?
If the pattern cabal is not in your path, prepend ~/.cabal/bin to your
path and export it. Then you can invoke executables in that directory
without giving the path on the command line.
But yes, if you're new to shell-scripting, it all looks geek to you :)
Now, hypothetically, I should have a Linux Haskell system, so I can
actually compile *anything* that's on Hackage.
Not really, you'll need to install external libraries (C stuff,
mostly) for many packages. But it should be a lot easier than on
Windows.
On Linux, it seems you install the development package, rerun Cabal, and
it it somehow knows that the library is installed and how to find in.
Mostly - there are a few standard locations for headers and libraries where
configure looks, but stuff for some packages must be queried for by
pkg-config, only some packages where that's necessary don't come with a .pc
file, oops.
On Windows... well, forget it. It'll never work, so you might as well
not bother trying.
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Re: [Haskell-cafe] OpenSUSE 11.2
Anyway, I'm currently attempting to get cabal-install to work... What's the problem? Downloading the .tar.gz from hackage, unpacking it and running bootstrap.sh *should* get you a working cabal-install with minimum fuss. No problem, I just haven't finished it yet. I just retried this and stumbled over a problem. I did a Google search and managed to navigate to here: http://www.haskell.org/cabal/download.html But this gives a download link for cabal-install 0.6.2, which doesn't work. Performing a second Google search and finding the *latest* cabal-install works. (But... why is this page not linking to the latest one? Or to Hackage, where the latest stable version lives...) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] jQuery is a monad
Nice blog post: http://importantshock.wordpress.com/2009/01/18/jquery-is-a-monad/ #g ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Lists of Existential DT
Or like this, with the benefit of using lists. data DrawableObj a = forall a.Drawable a = DrawableObj a a , b = DrawableObj a : b drawMany (a,b,c,[]) 2010/2/28 Miguel Mitrofanov miguelim...@yandex.ru: Sorry, no luck with that. But you can, probably, define some customized comma: data DrawPair a b = DrawPair a b (,) :: a - b - DrawPair a b (,) = DrawPair instance (Drawable a, Drawable b) = Drawable (DrawPair a b) where ... drawMany :: Drawable a = Window - a - IO () ... drawMany window $ image , text , otherImage On 28 Feb 2010, at 17:31, Yves Parès wrote: Hello! I have a class Drawable, and some datatypes which are instances of it, and I would like to be able to draw them all at once! drawMany window [image, text, otherImage] I think the type of the function drawMany would be: drawMany :: Window - [forall a. (Drawable a) = a] - IO () However it doesn't work. I know one solution is to make a new datatype (e.g. DrawableObj) which will be: data DrawableObj = forall a (Drawable a) = DrawableObj a And then declare drawMany as: drawMany :: Window - [DrawableObj] - IO () But to use it I have to wrap up myself every drawable in a DrawableObj: drawMany window [DrawableObj image, DrawableObj text, DrawableObj otherImage] Is there another more suitable way to handle a list of drawables? - Yves Parès Live long and prosper -- View this message in context: http://old.nabble.com/Lists-of-Existential-DT-tp27735354p27735354.html Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Eugene Kirpichov Senior Developer, JetBrains ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Real-time garbage collection for Haskell
On Sun, Feb 28, 2010 at 10:03 AM, Heinrich Apfelmus apfel...@quantentunnel.de wrote: Luke Palmer wrote: I have seen some proposals around here for SoC projects and other things to try to improve the latency of GHC's garbage collector. I'm currently developing a game in Haskell, and even 100ms pauses are unacceptable for a real-time game. I'm calling out to people who have seen or made such proposals, because I would be willing to contribute funding and/or mentor a project that would contribute to this goal. Also any ideas for reducing this latency in other ways would be very appreciated. Overly long garbage collection might also be a sign of space leaks. But there are many other things that can go wrong in a real time system and might explain your delays. For example, you might need to avoid amortized time data structures like Data.Sequence . Or for physics simulations, you'd need to fix the time step ∆t, as described in http://gafferongames.com/game-physics/fix-your-timestep/ or numerical integration will deteriorate rather quickly. Incidentally, what's described there is a simplified version of the frequency locked loops described in Massalin's thesis on Synthesis OS, and it is used there for about the same purpose in a soft real-time context. http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.29.4871 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Lists of Existential DT
jkff wrote: Or like this, with the benefit of using lists. data DrawableObj a = forall a.Drawable a = DrawableObj a a , b = DrawableObj a : b drawMany (a,b,c,[]) I like this solution, but it's a pity I think that Haskell doesn't provide a way to use types like [forall a. (Drawable a) = a], which obligates you to declare an extra datatype... - Yves Parès Live long and prosper -- View this message in context: http://old.nabble.com/Lists-of-Existential-DT-tp27735354p27737144.html Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Lists of Existential DT
You can actually write that type with impredicative polymorphism, but it doesn't do what you seem to want: it makes a list of polymorphic values (i.e., universally quantified ones, not existentially). But that's going away soon, anyway... On Sun, Feb 28, 2010 at 1:49 PM, Yves Parès limestr...@gmail.com wrote: jkff wrote: Or like this, with the benefit of using lists. data DrawableObj a = forall a.Drawable a = DrawableObj a a , b = DrawableObj a : b drawMany (a,b,c,[]) I like this solution, but it's a pity I think that Haskell doesn't provide a way to use types like [forall a. (Drawable a) = a], which obligates you to declare an extra datatype... - Yves Parès Live long and prosper -- View this message in context: http://old.nabble.com/Lists-of-Existential-DT-tp27735354p27737144.html Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] OpenSUSE 11.2
David Virebayre wrote:
On Sun, Feb 28, 2010 at 6:30 PM, Andrew Coppin
andrewcop...@btinternet.com mailto:andrewcop...@btinternet.com wrote:
Daniel Fischer wrote:
if [ -z `/bin/echo ${PATH} | /usr/bin/grep cabal` ]
then
export PATH=/home/andrew/.cabal/bin:$PATH
fi
in your .bashrc
Uh... what?
that snippet supposes you have cabal installed in your home directory
under the directory .cabal. The binary file would be in the bin
subdirectory of .cabal
Names that start with a . are hidden files/directories on linux, by
the way.
So the first line checks if you have cabal in your path list. If
not, on the 3rd line it supposes your home directory is /home/andrew
and adds the cabal binary directory to your path list.
Oh, right. So it's checking whether it's already in the search path
before adding it. I would have just added it. ;-) [And by the looks of
it, I would have got even that wrong...]
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Re: [Haskell-cafe] Lists of Existential DT
drawMany is just sequence dressed up a bit: I assume you have this class: class Drawable a where draw :: Drawable a = a - Window - IO () So, the key is to remember that functions and IO actions are first-class values! data Box = ... instance Drawable Box where ... box :: Box box = ... data Circle = ... instance Drawable Circle where ... circle :: Circle circle = ... instance Drawable String where ... with :: b - [b - a] - [a] with w = map ($ w) manyWith :: Monad m = w - [w - m a] - m () manyWith w = sequence . with w sample :: Window - IO () sample w = manyWith w $ [draw box, draw circle, draw hello] On Sun, Feb 28, 2010 at 6:31 AM, Yves Parès limestr...@gmail.com wrote: Hello! I have a class Drawable, and some datatypes which are instances of it, and I would like to be able to draw them all at once! drawMany window [image, text, otherImage] I think the type of the function drawMany would be: drawMany :: Window - [forall a. (Drawable a) = a] - IO () However it doesn't work. I know one solution is to make a new datatype (e.g. DrawableObj) which will be: data DrawableObj = forall a (Drawable a) = DrawableObj a And then declare drawMany as: drawMany :: Window - [DrawableObj] - IO () But to use it I have to wrap up myself every drawable in a DrawableObj: drawMany window [DrawableObj image, DrawableObj text, DrawableObj otherImage] Is there another more suitable way to handle a list of drawables? - Yves Parès Live long and prosper -- View this message in context: http://old.nabble.com/Lists-of-Existential-DT-tp27735354p27735354.html Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] OpenSUSE 11.2
Am Sonntag 28 Februar 2010 20:07:28 schrieb Andrew Coppin: Oh, right. So it's checking whether it's already in the search path before adding it. Right. I would have just added it. ;-) That wouldn't do much harm, you'd just have it several times in your $PATH (which means it'll take a little longer to find things in the places listed after because ~/.cabal/bin is searched multiple times). [And by the looks of it, I would have got even that wrong...] Let me guess, you'd have tried ';' as the path-separator? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] OpenSUSE 11.2
Daniel Fischer wrote: Let me guess, you'd have tried ';' as the path-separator? I didn't know you have to use export for this to work... ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: using haskell to serve with apache
-BEGIN PGP SIGNED MESSAGE- Hash: RIPEMD160 Hello Brad, I can't provide an anecdote, but you can run a native Haskell server like Happstack behind Apache and use mod_proxy to pass all requests to a certain vhost and/or path to it. Greets Ertugrul brad clawsie claw...@fastmail.fm wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 hi i'm currently doing some work on a personal site and was considering giving a haskell web tool a spin. i have a fairly complex apache configuration, so i don't want to try to replace it with a native haskell server, but instead use haskell via an interface to apache (i.e. something like wsgi, plack, etc). some searching shows hyena and yesod in various states of development, but i can't figure out if they are appropriate or ready for use. anyone have experiences using haskell behind apache? should i just try out something based on fastcgi? any anecdotes welcome thanks brad -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.10 (FreeBSD) iEYEARECAAYFAkuKoJEACgkQxRg3RkRK91PVJwCdFD4dS47KjJuMcNVZmPkYXKyU ItsAnRoYBE39XtXyXDluh+pHSxzP+Qcd =91Ql -END PGP SIGNATURE- - -- nightmare = unsafePerformIO (getWrongWife = sex) http://blog.ertes.de/ -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.14 (GNU/Linux) iQIcBAEBAwAGBQJLitCzAAoJENVqN/rl3Y0RgYYP/ivOySp2UG1nMTt3eXi6bhFH gdrx6fkc+iHxAoOEHiBLHCnMpxVGd0OmE6AOjZJZACJzK2K+EKQnBB/J7ZhOmDVH ZPcYyc48fZmCgZ67CC31at67TIAVJcpc/ixiiVH3yN1TtwFOuWsk4VtW4tRITXtL 1rgjq0hB8vogmSZCbHDuoRsAteXorBRnm7NfYxLCqT8okQSEESgmiEXGseS9GznC Q1QfFScgSqGEMNGN5USQd9xyvGudTF72VmBl9TAFZcJ3YE14EunY1W9RSCvuFNMn xXf5rvPutJP2Fzo3LQagCBtWS/1PgjBrKMecfXBXi6vTEIhx9u70WaaXWBtENdGf G8UwykQfcw3l/gUs2pJdlNWDRYripEG1HrnXE+BiQSdwiMEFRcK54BPgGtXHFJWN 6e6LaYUJCx0cmNVj8g71IX6qqmygi6QrIPfWJEPbR0VDyjRZKNFf+ZOqSQ7brR1f aJTw3XIvZAJVta6hfVWFnqrl7fm3xB8wIb5Ilvjv5LcSTkWCHy6kthuB8D/2MybQ u9F3CQ2iXY+EXsDDC8lV0kwOLhBDasGd65V6x/PS2nG/7smYH1FUDi58ns2BwUxH YGAMWHOmVeNF7j3uIuZngoqgd8ppFvmoyORyGdLAga2LQV7/nibki54aeoq0tFjN ZS4x1/jh/nYXANajezT2 =zOei -END PGP SIGNATURE- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] OpenSUSE 11.2
Am Sonntag 28 Februar 2010 20:40:15 schrieb Andrew Coppin: Daniel Fischer wrote: Let me guess, you'd have tried ';' as the path-separator? I didn't know you have to use export for this to work... You probably wouldn't need export in SUSE, there $HOME/.bashrc is sourced in /etc/profile (I don't expect they changed that from 11.1 to 11.2) and PATH is exported afterwards, so you'd have ~/.cabal/bin in the path of every shell started from the first bash on (and without the test if it's already there, the n-th shell would have n copies of ~/.cabal/bin in its path). But in other setups, without export ~/.cabal/bin might not be in the path of non-bash subshells. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Lists of Existential DT
On Sun, Feb 28, 2010 at 6:31 AM, Yves Parès limestr...@gmail.com wrote: Hello! I have a class Drawable, and some datatypes which are instances of it, and I would like to be able to draw them all at once! drawMany window [image, text, otherImage] I think the type of the function drawMany would be: drawMany :: Window - [forall a. (Drawable a) = a] - IO () However it doesn't work. I know one solution is to make a new datatype (e.g. DrawableObj) which will be: data DrawableObj = forall a (Drawable a) = DrawableObj a And then declare drawMany as: drawMany :: Window - [DrawableObj] - IO () But to use it I have to wrap up myself every drawable in a DrawableObj: drawMany window [DrawableObj image, DrawableObj text, DrawableObj otherImage] Is there another more suitable way to handle a list of drawables? Luke Palmer has an article on his blog that proposes a different solution to the problem that I believe you're trying to solve: http://lukepalmer.wordpress.com/2010/01/24/haskell-antipattern-existential-typeclass/ You might give his approach a try and see if it's simpler and easier to work with. Good luck! Jason ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] OpenSUSE 11.2
Andrew Coppin wrote: Now, hypothetically, I should have a Linux Haskell system, so I can actually compile *anything* that's on Hackage. Heh, I forgot how much fun building Gtk2hs is. ;-) The only library I've ever seen that takes more than 11 seconds to build... (Currently at 10 *minutes* and counting!) Oh, and it seems to not want to build with GHC 6.12.1. Is that normal, or did I do something wrong? (It seems to be building just fine with GHC 6.10.4...) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] using haskell to serve with apache
I just run a happstack server on an alternative port, and then use mod_proxy to forward requests to the alternative port. For example, happstack.com is hosted at: http://src.seereason.com:9021/ but apache on that machine has a happstack.com config that looks like: VirtualHost *:80 ServerAdmin u...@example.org ServerName www.happstack.com ServerAlias happstack.com ErrorLog /var/log/apache2/happstack.com/error.log CustomLog /var/log/apache2/happstack.com/access.log combined ProxyRequests Off Proxy * AddDefaultCharset off Order deny,allow Deny from all /Proxy Proxy http://127.0.0.1:9021/* AddDefaultCharset off Order deny,allow Allow from all /Proxy ProxyPass / http://127.0.0.1:9021/ ProxyPassReverse / http://127.0.0.1:9021/ /VirtualHost - So users can just visit http://happstack.com/ Hopefully I have not done something horribly insecure (easy to do with apache), but I believe this is correct. - jeremy On Sun, Feb 28, 2010 at 10:57 AM, brad clawsie claw...@fastmail.fm wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 hi i'm currently doing some work on a personal site and was considering giving a haskell web tool a spin. i have a fairly complex apache configuration, so i don't want to try to replace it with a native haskell server, but instead use haskell via an interface to apache (i.e. something like wsgi, plack, etc). some searching shows hyena and yesod in various states of development, but i can't figure out if they are appropriate or ready for use. anyone have experiences using haskell behind apache? should i just try out something based on fastcgi? any anecdotes welcome thanks brad -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.10 (FreeBSD) iEYEARECAAYFAkuKoJEACgkQxRg3RkRK91PVJwCdFD4dS47KjJuMcNVZmPkYXKyU ItsAnRoYBE39XtXyXDluh+pHSxzP+Qcd =91Ql -END PGP SIGNATURE- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Has Try Haskell! An interactive tutorial in your browser been announced yet?
There is a link to Try Haskell! -- an interactive, online Haskell interpreter (see http://tryhaskell.org/) under February 2010 under 1 Headlines on the Haskell - HaskellWIki Web page (see http://www.haskell.org/). While I could be mistaken, there do not seem to be any announcements for February 2010 concerning this interactive tutorial on either the Haskell or Haskell-Cafe mailing lists. Has it been announced yet? If not, can I go ahead and announce it on the Haskell mailing list? -- Benjamin L. Russell -- Benjamin L. Russell / DekuDekuplex at Yahoo dot com http://dekudekuplex.wordpress.com/ Translator/Interpreter / Mobile: +011 81 80-3603-6725 Furuike ya, kawazu tobikomu mizu no oto. -- Matsuo Basho^ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal pre-compiled packages
On 28 February 2010 01:55, Diego Souza dso...@bitforest.org wrote: currently when one install a cabal package it compiles it and then install generated binaries. I wonder whether or not it would be useful to have pre-compiled binaries as many package managers usually do (e.g. apt). I often think that would save some time on the expense of a busier hackage server capable of generating packages for many different platforms. I'm particularly thinking on the following scenario: suppose that you have code that is ready for production. If cabal supported pre-compiled binaries, there is no need to install ghc or eventually any other compiler, just runtime environment and eventually cabal. I must say that I have no experience in doing this in Haskell (just personal/small projects), so I suppose one have to generate binaries and use other sort of package manager to deploy code to production (which sounds reasonable as well). Thus, if the assumption is correct, cabal is a development tool, not something one could to only deploy runtime-only packages. So, you need a binary for each version of GHC available (IIRC, Duncan is still testing new releases of Cabal for versions of GHC as old as 6.4) with and without profiling, with different possible optimization flags and for different architectures and operating systems... To me, that sounds like too much work. /me really wishes people stopped thinking of Cabal as a package manager -- Ivan Lazar Miljenovic ivan.miljeno...@gmail.com IvanMiljenovic.wordpress.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] OpenSUSE 11.2
Am Sonntag 28 Februar 2010 22:57:05 schrieb Andrew Coppin: Andrew Coppin wrote: Now, hypothetically, I should have a Linux Haskell system, so I can actually compile *anything* that's on Hackage. Heh, I forgot how much fun building Gtk2hs is. ;-) But that's not yet on hackage :) The only library I've ever seen that takes more than 11 seconds to build... (Currently at 10 *minutes* and counting!) Oh, and it seems to not want to build with GHC 6.12.1. Is that normal, Yes, as far as I know, there's no gtk2hs release for 6.12 yet. or did I do something wrong? (It seems to be building just fine with GHC 6.10.4...) There's a version for 6.10.4, so that ought to build indeed. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Has Try Haskell! An interactive tutorial in your browser been announced yet?
Benjamin L. Russell wrote: There is a link to Try Haskell! -- an interactive, online Haskell interpreter (see http://tryhaskell.org/) under February 2010 under 1 Headlines on the Haskell - HaskellWIki Web page (see http://www.haskell.org/). While I could be mistaken, there do not seem to be any announcements for February 2010 concerning this interactive tutorial on either the Haskell or Haskell-Cafe mailing lists. Has it been announced yet? If not, can I go ahead and announce it on the Haskell mailing list? I discovered this approximately 17 seconds ago, and I was just about to ask the exact same thing... This should *definitely* make it into the HWN. ;-) The tutorial is quite nice too, although rather incomplete. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] View patterns
On 28 February 2010 05:55, Andrew Coppin andrewcop...@btinternet.com wrote: It won't work for arbitrarily complex structures, however. My main point was that if you make the constructors abstract and provide functions to query the structure, now you can't pattern match against it. We do, however, have guards which helps reduce the boiler plate (nested if statements, etc.). -- Ivan Lazar Miljenovic ivan.miljeno...@gmail.com IvanMiljenovic.wordpress.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Has Try Haskell! An interactive tutorial in your browser been announced yet?
DekuDekuplex: There is a link to Try Haskell! -- an interactive, online Haskell interpreter (see http://tryhaskell.org/) under February 2010 under 1 Headlines on the Haskell - HaskellWIki Web page (see http://www.haskell.org/). While I could be mistaken, there do not seem to be any announcements for February 2010 concerning this interactive tutorial on either the Haskell or Haskell-Cafe mailing lists. Has it been announced yet? If not, can I go ahead and announce it on the Haskell mailing list? The author says it is work in progress http://www.reddit.com/r/haskell/comments/b7dil/try_haskell_now_with_t_and_wip_interactive/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Has Try Haskell! An interactive tutorial in your browser been announced yet?
Andrew Coppin andrewcop...@btinternet.com writes: Benjamin L. Russell wrote: There is a link to Try Haskell! -- an interactive, online Haskell interpreter (see http://tryhaskell.org/) under February 2010 under 1 Headlines on the Haskell - HaskellWIki Web page (see http://www.haskell.org/). While I could be mistaken, there do not seem to be any announcements for February 2010 concerning this interactive tutorial on either the Haskell or Haskell-Cafe mailing lists. Has it been announced yet? If not, can I go ahead and announce it on the Haskell mailing list? I discovered this approximately 17 seconds ago, and I was just about to ask the exact same thing... This should *definitely* make it into the HWN. ;-) The tutorial is quite nice too, although rather incomplete. Then I'll go ahead and announce this on the Haskell mailing list. -- Benjamin L. Russell -- Benjamin L. Russell / DekuDekuplex at Yahoo dot com http://dekudekuplex.wordpress.com/ Translator/Interpreter / Mobile: +011 81 80-3603-6725 Furuike ya, kawazu tobikomu mizu no oto. -- Matsuo Basho^ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal pre-compiled packages
Am Sonntag 28 Februar 2010 23:20:00 schrieb Ivan Miljenovic: /me really wishes people stopped thinking of Cabal as a package manager /me really wishes there were package managers as useful and easy as Cabal for things other than Haskell :D ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Linear programming in Haskell
Louis Wasserman schrieb: Yo, Man, I'd never used FFI before, but it's really not as scary as I'd feared. I've implemented a more comprehensive interface to GLPK's simplex solver and -- rather importantly, for my own needs -- its MIP solver. This doesn't depend on hmatrix, and in fact, it doesn't require any matrix or vector manipulation at all -- linear functions are specified as a straight-up Data.Map from an arbitrary variable type to their coefficients. The library is now available as glpk-hs on hackage. Example: import Data.LinearProgram.LPMonad import Data.LinearProgram import Data.LinearProgram.GLPK objFun :: LinFunc String Int objFun = linCombination [(10, x1), (6, x2), (4, x3)] lp :: LP String Int lp = execLPM $ dosetDirection Max setObjective objFun leqTo (varSum [x1, x2, x3]) 100 leqTo (10 *^ var x1 ^+^ 4 * x2 ^+^ 5 *^ var x3) 600 -- c *^ var v, c * v, and linCombination [(c, v)] are all equivalent. -- ^+^ is the addition operation on linear functions. leqTo (linCombination [(2, x1), (2, x2), (6, x3)]) 300 varGeq x1 0 varBds x2 0 50 varGeq x3 0 setVarKind x1 IntVar setVarKind x2 ContVar Using strings for variable names you cannot check for undefined variables. How about adding a function for generating new variables to your LP monad? The example may then look like do setDirection Max setObjective objFun x1 - newVariable x2 - newVariable x3 - newVariable leqTo (varSum [x1,x2,x3]) 100 ... ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Linear programming in Haskell
For reference: any Ord type can be used as a variable. (It's pretty sweet.) However, you have a good point. I just uploaded the newest version, which provides a newVariables monad operation for Enums. (This makes a key assumption that any element of [v..] will compare as greater than or equal to v, and that only the first element is equal to v...but that's true for most Enum implementors, and certainly most of the ones you'd be using as variables.) Now, your method would look like [x1, x2, x3] - newVariables 3 Alternately, (x1:x2:x3:_) - newVariables' -- returns an infinite list It's an expensive operation, though -- since I don't track the set of all variables as the LP is built, I need to construct the set of all variables before generating new ones -- so it's recommended that you get all the variables you need in one or two passes. (The new version has a few other neat features, like exporting/importing from CPLEX LP files. I've kind of been overdoing the Haskell lately...) Louis Wasserman wasserman.lo...@gmail.com http://profiles.google.com/wasserman.louis On Sun, Feb 28, 2010 at 5:24 PM, Henning Thielemann schlepp...@henning-thielemann.de wrote: Louis Wasserman schrieb: Yo, Man, I'd never used FFI before, but it's really not as scary as I'd feared. I've implemented a more comprehensive interface to GLPK's simplex solver and -- rather importantly, for my own needs -- its MIP solver. This doesn't depend on hmatrix, and in fact, it doesn't require any matrix or vector manipulation at all -- linear functions are specified as a straight-up Data.Map from an arbitrary variable type to their coefficients. The library is now available as glpk-hs on hackage. Example: import Data.LinearProgram.LPMonad import Data.LinearProgram import Data.LinearProgram.GLPK objFun :: LinFunc String Int objFun = linCombination [(10, x1), (6, x2), (4, x3)] lp :: LP String Int lp = execLPM $ dosetDirection Max setObjective objFun leqTo (varSum [x1, x2, x3]) 100 leqTo (10 *^ var x1 ^+^ 4 * x2 ^+^ 5 *^ var x3) 600 -- c *^ var v, c * v, and linCombination [(c, v)] are all equivalent. -- ^+^ is the addition operation on linear functions. leqTo (linCombination [(2, x1), (2, x2), (6, x3)]) 300 varGeq x1 0 varBds x2 0 50 varGeq x3 0 setVarKind x1 IntVar setVarKind x2 ContVar Using strings for variable names you cannot check for undefined variables. How about adding a function for generating new variables to your LP monad? The example may then look like do setDirection Max setObjective objFun x1 - newVariable x2 - newVariable x3 - newVariable leqTo (varSum [x1,x2,x3]) 100 ... ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Real-time garbage collection for Haskell
On Sun, Feb 28, 2010 at 2:06 AM, Pavel Perikov peri...@gmail.com wrote: Did you really seen 100ms pauses?! I never did extensive research on this but my numbers are rather in microseconds range (below 1ms). What causes such a long garbage collection? Lots of allocated and long-living objects? This is all hypothetical right now. I heard some horror stories in which people had to switch to the main game loop in C++ and only do the AI logic in Haskell because of pauses. I would rather not do that, especially because this project is *about* proving Haskell as a viable game development platform. So I am trying to be prepared if I do see something like that, so that it doesn't put the show on hold for a few months. Presumably large, long-living objects would cause the generation 0 collections to take a long time. I am not sure if we will have any said objects, but we can't rule it out... Thanks for the positive reassurances, at least. I'd like to hear from people with the opposite experience, if there are any. Luke ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] ANNOUNCE: jhc-0.7.3
It's been a long time coming, but jhc-0.7.3 is here. If you have been following the darcs repository, there are not a whole lot of new changes, but there have been substantial fixes since 0.7.2 for those that use the tarballs or rpms. http://repetae.net/computer/jhc/ One of the most important ones is I have begun the process of standardizing on YAML for all external interfaces that may be useful to automation, this should make interfacing jhc with external tools written in any language much easier, and it will prevent me from spending time trying to invent proprietary formats every time I think of something new to spit out. right now it is used in 3 places: - dumping dependency info with --deps - library dumping with --list-libraries -v - annotating source code, for inputting to documentation generators via --annotate-source The main place it isn't used yet that I desire too is to replace the 'cabal' library description format with a true YAML file. jhc cabal files were never quite compatible with cabal ones anyway and naming them the same thing has been a source of connfusion. some of the other changes have been: features: - a lot more regression tests, many user submitted bugs are now regressions (or fixed) - support for using 'mock' to build rpms - System.Exit, System.Cmd added to base - better compatibility with ghc in some library functions - ui improvements in showing progress and errors - extended --list-libraries info - --deps dependency dumping - more francise compatible thanks to patches from droundy - more instances for bigger tuples added - uses editline if readline not available - select libraries by hash as well as version - add System.IO.Pipe - detect version of gcc needed for cross compiling to windows performance: - storage analysis - a very basic region inference enabled by default - deadcode analysis can see through partial applications now - profiled and sped up some library routines that were producing inellegant core. - figure out when top level grin functions call themselves recursively and turn them into explicit loops. bug fixes: - do expression in infix - fix strict newtype bug - U2U bug fixed - desugaring inside of list comprehensions fix - c generator doesn't mess up on unknown values - the compiler version is stored in the cache files, so multiple versions of jhc don't clobber each others cache entries - Ord instance for lists fixed - recursive type synonyms detected properly - make sure errno.h is included when errno is referenced - don't give a parse error when seeing ghc extensions to INLINE - qualified method names fix John -- John Meacham - ⑆repetae.net⑆john⑈ - http://notanumber.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Haskell Weekly News: Issue 151 - February 28, 2010
--- Haskell Weekly News http://sequence.complete.org/hwn/20100228 Issue 151 - February 28, 2010 --- Welcome to issue 151 of HWN, a newsletter covering developments in the [1]Haskell community. A light HWN this week, some interesting discussion about view patterns and free monads. Also announced this week was [2]TryHaskell a work-in-progress online interactive haskell interpreter and tutorial. The author (based on his reddit post) has asked us not to post this to proggit yet, but I don't think he'll mind a plug here. So after you're done reading, give it a try! Until next week, haskellers, your Haskell Weekly News. Announcements wxHaskell for ghc-6.12.1. Daniel Fischer [3]announced a new release of wxHaskell. concurrent-extra-0.2. Roel van Dijk [4]announced a new release of concurrent-extra jhc-0.7.3. John Meacham [5]announced a new version of jhc, including many bug fixes. Try Haskell! An interactive tutorial in your browser. Benjamin L. Russell [6]told us about the TryHaskell Project, available at [7]TryHaskell.org. TryHaskell is an interactive, online Haskell interpreter and tutorial. MSFP: Call for Papers. Venanzio Capretta [8]announced a call for papers for the Third Workshop on Mathematically Structured Functional Programming. HLedger 0.8. Simon Michael [9]announced a new version of hledger last week, but it slipped through my radar. This release includes bug fixes, some refactoring, and High-Res Graphical Chart generation capability. Discussion View patterns. Andrew Coppin [10]asked about making view patterns polymorphic. What are 'free' Monads? Guenther Schmidt [11]asked what exactly it meant to be a 'free monad' Multiple Interpretations for a monad? Guenther Schmidt [12]asked about monads which can have multiple levels of meaning and interpretation. Blog noise [13]Haskell news from the [14]blogosphere. Blog posts from people new to the Haskell community are marked with , be sure to welcome them! * Joachim Breitner: [15]Exploiting sharing in arbtt. * Martijn van Steenbergen: [16]Colors in GHCi. * Don Stewart (dons): [17]Evaluation strategies and synchronization: things to watch for. * Don Stewart (dons): [18]Fusion makes functional programming fun!. * Michael Snoyman: [19]Simpler is Better. * Kevin Reid (kpreid): [20]Hvm.hs: an exercise in Haskell golf. * Bryn Keller: [21]Why Isn't Cabal Installed with GHC?. * Don Stewart (dons): [22]Modern Benchmarking in Haskell. Quotes of the Week * roconnor: sounds like you need a zygohistomorphic prepromorphism * copumpkin: These are not the monads you are looking for. * noggle: this language is like having programming super powers About the Haskell Weekly News New editions are posted to [23]the Haskell mailing list as well as to [24]the Haskell Sequence and [25]Planet Haskell. [26]RSS is also available, and headlines appear on [27]haskell.org. To help create new editions of this newsletter, please see the information on [28]how to contribute. Send stories to jfredett . at . gmail . dot . com. The darcs repository is available at darcs get [29]http://patch-tag.com/r/jfredett/HWN2/pullrepo HWN2 . References 1. http://haskell.org/ 2. http://tryhaskell.org/ 3. http://article.gmane.org/gmane.comp.lang.haskell.cafe/70857 4. http://article.gmane.org/gmane.comp.lang.haskell.cafe/70689 5. http://article.gmane.org/gmane.comp.lang.haskell.cafe/70961 6. http://article.gmane.org/gmane.comp.lang.haskell.general/17819 7. http://tryhaskell.org/ 8. http://article.gmane.org/gmane.comp.lang.haskell.general/17818 9. http://www.haskell.org/pipermail/haskell-cafe/2010-February/073185.html 10. http://article.gmane.org/gmane.comp.lang.haskell.cafe/70895 11. http://article.gmane.org/gmane.comp.lang.haskell.cafe/70874 12. http://article.gmane.org/gmane.comp.lang.haskell.cafe/70800 13. http://planet.haskell.org/ 14. http://haskell.org/haskellwiki/Blog_articles 15. https://www.joachim-breitner.de/blog/archives/381-Exploiting-sharing-in-arbtt.html 16. http://martijn.van.steenbergen.nl/journal/2010/02/27/colors-in-ghci/ 17. http://donsbot.wordpress.com/2010/02/26/evaluation-strategies-and-synchronization-things-to-watch-for/ 18. http://donsbot.wordpress.com/2010/02/26/fusion-makes-functional-programming-fun/ 19. http://snoyberg.wordpress.com/2010/02/26/simpler-is-better/ 20. http://kpreid.livejournal.com/23060.html 21. http://www.xoltar.org/?p=33 22. http://donsbot.wordpress.com/2010/02/23/modern-benchmarking-in-haskell/ 23. http://www.haskell.org/mailman/listinfo/haskell 24. http://sequence.complete.org/ 25. http://planet.haskell.org/ 26. http://sequence.complete.org/node/feed 27
[Haskell-cafe] Is the Summer of Code TRAC relevant for this years SoC?
Hello. I was looking into the possibility of doing Summer of Code as a student, when I found Haskell.org's TRAChttp://hackage.haskell.org/trac/summer-of-code/report/1. I was particularly interested in Efficient Maps using Generalised Trees and the New Purely Functional Data Structures/Containers Library. I'd love to work on either of those, but are they or any of the projects listed on the TRAC still relevant, or are they just the leftovers from SoC 2009? -Nathan Hunter ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Computer Graphics and Haskell - Radiosity Methods
Hello cafe, While I was studying for my computer graphics test I have tomorrow I realized that maybe some of the major problems I've read so far about Radiosity Rendering Algorithms may be reduced significantly if it was implemented in Haskell and taking advantage of the lazy evaluation so that only what can be seen from the viewer's perspective point of view is calculated, and the rest of the scene just remains as thunks waiting for them to be calculated in case they are needed. I guess that probably most of the people on this list doesn't really work on the computer graphics area, but if anybody out there actually does I'd really like if he or she could explain me more of why what I'm saying could be really useful and what has already been done (or why I'm so lost that I'm probably gonna fail my exam tomorrow hahaha)... One of the things I'm studying is the Monte Carlo Radiosity Methods which takes advantages of non-determinism to create stochastic algorithms, I guess this is more difficult to implement in Haskell, please if you know any of this Monte Carlo Methods for Radiosity Algorithms share that knowledge with me (and the list). Thank you, Hector Guilarte ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Is the Summer of Code TRAC relevant for this years SoC?
enferris: Hello. I was looking into the possibility of doing Summer of Code as a student, when I found Haskell.org's TRAC. I was particularly interested in Efficient Maps using Generalised Trees and the New Purely Functional Data Structures/Containers Library. I'd love to work on either of those, but are they or any of the projects listed on the TRAC still relevant, or are they just the leftovers from SoC 2009? We'll set it up for 2010. Also look at the haskell-proposals reddit for ideas people in the community have recently proposed. The key is to find something relevant to lots of people. http://www.reddit.com/r/haskell_proposals -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Computer Graphics and Haskell - Radiosity Methods
you could have a look at these ... bjpop-ray - search on web hray - http://users.elis.ugent.be/~kehoste/Haskell/HRay/ Hello cafe, While I was studying for my computer graphics test I have tomorrow I realized that maybe some of the major problems I've read so far about Radiosity Rendering Algorithms may be reduced significantly if it was implemented in Haskell and taking advantage of the lazy evaluation so that only what can be seen from the viewer's perspective point of view is calculated, and the rest of the scene just remains as thunks waiting for them to be calculated in case they are needed. I guess that probably most of the people on this list doesn't really work on the computer graphics area, but if anybody out there actually does I'd really like if he or she could explain me more of why what I'm saying could be really useful and what has already been done (or why I'm so lost that I'm probably gonna fail my exam tomorrow hahaha)... One of the things I'm studying is the Monte Carlo Radiosity Methods which takes advantages of non-determinism to create stochastic algorithms, I guess this is more difficult to implement in Haskell, please if you know any of this Monte Carlo Methods for Radiosity Algorithms share that knowledge with me (and the list). Thank you, Hector Guilarte ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
