Re: [Haskell-cafe] Dual-licensing the package on Hackage
Perhaps it would be best if .cabal allowed to have more than one license listed. Another solution would be to use custom field, for example: License: GPL x-Other-License: Commercial, see License-Commercial.txt All best, Krzysztof Skrzętnicki On Tue, Jul 30, 2013 at 11:44 AM, David Sorokin david.soro...@gmail.comwrote: Thanks Thu, I agree with you. Just I don't know what to write in the license field of the .cabal file: GPL or OtherLicense. The both choices seem correct to me and misleading at the same time. Cheers, David 30.07.2013, в 12:53, Vo Minh Thu написал(а): 2013/7/30 David Sorokin david.soro...@gmail.com: Hi, Cafe! Probably, it was asked before but I could not find an answer with help of Google. I have a library which is hosted on Hackage. The library is licensed under BSD3. It is a very specialized library for a small target group. Now I'm going to relicense it and release a new version already under the dual-license: GPLv3 and commercial. In most cases GPL will be sufficient as this is not a library in common sense. Can I specify the GPL license in the .cabal file, or should I write OtherLicense? I'm going to add the information about dual-licensing in the description section of the .cabal file, though. Although you can indeed license your software under different licences, in the case of your question it doesn't seem to be a concern with Hackage: The license displayed on Hackage is the one for the corresponding .cabal file (or at least I think it is). So you issue your new version with the changed license, the new version is available with the new license, the old versions are still available with the old license. Everything is fine. Now about the dual licensing. It seems it is again not a problem with Hackage: you are not granting through Hackage such a commercial license. I guess you provide it upon request (for some money). I.e. when I download your library from Hackage, I receive it under the terms of the BSD (or GPL) license you have chosen, not under a commercial license that I would have to receive through other means. Otherwise the semantic of the license field on Hackage would mean the library is available under such and such licenses, which are not granted to you when you download the library on Hackage. Only when you download the package you can actually find the licensing terms (e.g. in the LICENSE file). But this seems unlikely to me. Cheers, Thu ___ 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] Performance difference between Linux and Windows?
The difference is roughly 2x, which suggests difference in Int/pointer sizes: 32bit vs 64bit. Indeed, only since 7.6.1. GHC supports compiling 64 bit executables on Windows ( http://hackage.haskell.org/trac/ghc/wiki/WindowsGhc). That means that in fact you compare 32 bit vs 64 bit programs. I didn't have a look at the code so this is just a wild guess. Best regards, Krzysztof Skrzętnicki On Fri, May 31, 2013 at 3:26 PM, James Jones jejones3...@gmail.com wrote: I've been having a great deal of fun writing a program to solve this year's Code Jam Fair and Squareproblem in Haskell (and learning about Haskell in the process). Having gotten it to work, I've been optimizing it as best I can. I'm not quite in Captain Ahab mode, but before I let it go I would like to find out what's behind a difference I've seen compiling and running the program under Linux and under Windows 7. Profiling it under Linux (compiled with GHC 7.4.1), it had a total allocation of 165,375,112 bytes. I had an opportunity to compile and run on Windows 7, with GHC 7.4.2. I expected it to run faster, since the Windows computer had a 3.1 GHz i7 and my Linux computer has a 2.8 GHz AMD Propus, but what I didn't expect was that the total allocation on the Windows version was 88,438,372 bytes! Thinking it might be due to a compiler improvement, I upgraded my Linux computer to Ubuntu 13.04 so I could get a newer GHC, but it didn't make much difference: total allocation 163,248,688 bytes. So, I'm wondering: what is it about either the Windows implementation or GHC 7.4.2 in particular that would make a factor of two difference in memory allocation? Should anyone wish to compile the program, let me know the best way to make the source available and I will happily do so; I also use Twan van Laarhoven's semilattice search tree code available at http://twanvl.nl/blog/haskell/SemilatticeSearchTree. James Jones ___ 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] using a win32 dll
My first guess would be missing -l parameter. The examples you have linked
read:
ghc --make compname.hs -lkernel32
Best regards,
Krzysztof Skrzętnicki
On Wed, May 29, 2013 at 9:13 AM, Kees Bleijenberg
k.bleijenb...@lijbrandt.nl wrote:
I made a Delphi dll (32 bits windows). This dll exports a function named
getPngVersion. This is a function with no arguments that returns a pointer
to a array of chars.
If I examine the dll with a tools like tdump, I can see the function
getPngVersion on index 1.
Now I want to use this dll in Haskell:
** **
{-# LANGUAGE ForeignFunctionInterface #-}
module Main(
main
)
** **
where
import Control.Monad
import Foreign.C
import Foreign.Marshal.Alloc
import Foreign.Marshal.Array
import System.Win32.Types
** **
foreign import stdcall glasPng getPngVersion getPngDllVersion :: IO
CString
** **
main :: IO ()
main = do
s - getPngDllVersion
putStrLn (show s)
** **
Compiling this with ghc --make glasPng.hs gives:
GlasPng.o: fake: (.text +0x82): undefined reference to ‘getPngVersion@0’
collect2 : Id returned 1 exit status
** **
I wonder what went wrong. In the foreign import line I use “glasPng…. “ to
tell ghc, it has to searh in glasPng.dll (changing glasPng to glasPng.dll
doesn’t help). I’ve changed the name of the function in the dll to
getPngVersion@0 but no luck. I’ve read and tested the last example at
http://stackoverflow.com/questions/1027246/haskell-foreign-import-stdcall-on-dll-function
(win32_getComputername, this works!). I wonder how haskell knows which
dll to use in this example?)
Probably I’am doing something wrong with the way I tell ghc which dll to
link or….
** **
Any ideas?
** **
Kees
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[Haskell-cafe] Reinventing a solution to configuration problem
Hello Cafe,
I came up with (actually reinvented [1]) a solution to configuration
problem. For example configuration:
data Config = Config { port :: Int, verbosity :: Int, logfile :: FilePath }
deriving Show
the basic idea is to use implicit parameters:
runServer :: (?config :: Config) = IO ()
The problem is that it is tiresome to decorate all functions in this way.
It is also non composable. For example if we switch to using two separate
configuration entities like this:
data LogConfig = LogConfig { verbosity :: Int, logfile :: FilePath }
data NetConfig = NetConfig { port :: Int }
we suddenly have to fix types all over the place. Yuck.
The extended idea here (compared to [2]) is to use type synonym with all
required parameters. This is simple (but requires at least Rank2Types):
type ConfIO a = (?config :: Config) = IO a
All the functions requiring config will now be simply in ConfIO monad which
is really IO with a bonus. A great feature of this solution is that we
don't need to use liftIO anywhere.
The core *problem* with this approach is that at least current version of
GHC fails to propagate implicit parameters the way it propagate typeclass
requirements. For example I would like the following function to have
(inferred) type
-- printConfig :: (?config :: Config) = IO ()
printConfig = print (?config :: Config)
Instead GHC will complain about unbound implicit parameter. Similar problem
from GHCi session:
Prelude let f = print (?conf :: Int)
interactive:11:16:
Unbound implicit parameter (?conf::Int)
arising from a use of implicit parameter `?conf'
In the first argument of `print', namely `(?conf :: Int)'
In the expression: print (?conf :: Int)
In an equation for `f': f = print (?conf :: Int)
For reason I don't fully understand this is fixed by disabling monomorphic
restriction. The documentation mentions the problem but in a different
context:
http://www.haskell.org/ghc/docs/latest/html/users_guide/other-type-extensions.html#idp49108928
*TL;DR*: A nice solution to configuration problem is to use implicit
parameters and type synonym for IO monad extended with implicit
configuration parameters. It requires Rank2Types for defining the synonym
and NoMonomorphismRestriction for lightweight use.
Best regards,
Krzysztof Skrzętnicki
[1] I only realised this after starting the writing of this email. The
implicit parameters solution is given at least in [2]. Somehow I didn't
came across it before.
[2] Global Variables in Haskell
(2004)http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.23.145rep=rep1type=ps
by
John Hughes
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Re: [Haskell-cafe] ghc-7 -fPIC error
Hello, please see this thread which I think is about the same issue you are seeing: http://www.haskell.org/pipermail/haskell-cafe/2012-June/102023.html In short, this is apparently caused by broken GCC. The solution is to use build.mk with disable optimizations or download from http://justhub.org/download which packages GHC for RHEL/CentOS/... GhcLibWays = v SRC_HC_OPTS= -H64m -O0 -fasm# -O -H64m GhcStage1HcOpts= -O -fasm GhcStage2HcOpts= -O0 -fasm # -O2 -fasm GhcLibHcOpts = -O -fasm # -O2 -XGenerics GhcHcOpts = -Rghc-timing # GhcLibWays += p # GhcLibWays += dyn NoFibWays = STRIP_CMD = : Also cc-ing Chris Dornan of justhub.org. Best regards, Krzysztof Skrzętnicki On Tue, Apr 30, 2013 at 4:05 AM, Christopher Howard christopher.how...@frigidcode.com wrote: Hey guys, this probably isn't the official GHC mailing list, but I've been trying to build and install a new GHC on an old RHEL5 system, as mentioned in my previous Cafe thread. I was able to make some good headway: I installed a ghc-6.8 binary, and then used that to build ghc-6.10 source, and then used that to build ghc-6.12 source. The idea is to keep going until I get to ghc-7.6. However, when I get to 7.0, my builds all eventually die with this error: quote: /usr/bin/ld: rts/dist/build/RtsStartup.dyn_o: relocation R_X86_64_PC32 against `StgRun' can not be used when making a shared object; recompile with -fPIC /usr/bin/ld: final link failed: Bad value collect2: ld returned 1 exit status After this failed the first time, I tried adding -fPIC to SRC_HC_OPTS, GhcStage1HcOpts, and so forth in build.mk. But ultimately I get the same error. I tried skipping a version and building ghc-7.2 instead, but the same error pops up. -- frigidcode.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] how do i get cabal to reinstall dependencies with profiling enabled?
Another option: use cabal-dev with --enable-library-profiling. It should do the trick. Best regards, Krzysztof Skrzętnicki On Wed, Apr 17, 2013 at 11:13 PM, Anatoly Yakovenko aeyakove...@gmail.comwrote: ___ 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] GSoC Project Proposal: Markdown support for Haddock
I think this thread has went to became a quest for One True Markup Language... I would like to propose a different approach: while we are at extending Haddock why not make it possible to choose from a set of different documentation plugins? Something that works akin to the type: Text - Environment - Documentation, where Documentation is Haddock AST (possibly extended)? That would make most people happy and put the source code writer in power: they could choose the syntax they would like to write their docs. Whether it is Haddock markup, Github Markdown, RST or OneTrueMarkup (c) (r) (patented). The task of defining such an API could be actually harder than writing support for any particular syntax but I think it is more beneficiary in the long run. *Bonus points:* provide the integration with .cabal files so that each package can inform which plugins it expects. *Extra bonus points:* let the plugin be simply the name of a function (or datatype that implements a typeclass) which in turn would be taken from a well-defined scope. (think: library that can provide its own plugin for documenting itself). Best regards, Krzysztof Skrzętnicki On Fri, Apr 5, 2013 at 4:24 AM, Richard A. O'Keefe o...@cs.otago.ac.nzwrote: On 5/04/2013, at 2:00 PM, Johan Tibell wrote: Would it be too much to ask that a notation be used which has a formal syntax and a formal semantics? We will document our superset, sure. That's what others did as well. The point is using Markdown as the shared base. Nononono. Sure, the others documented their supersets. But they did *NOT* provide what I am asking for: - a FORMAL SYNTAX and - a FORMAL SEMANTICS. I tried to use one of these systems, and found myself unable to determine which combinations of features were legal and what legal combinations of features *meant*. I corresponded with some people who had built markdown parsers, and the answer was the same each time: they had reversed engineered some other parser (typically a Perl one) and bashed on it until they were bug-compatible. If I want to get a particular effect in LaTeX or even in HTML+CSS, I can usually figure it out *without* having to run any program. If I want to get a particular effect in Markdown, I flounder around and end up doing without. I am sick of documentation that vaguely hints at things, and I am especially sick of Markdown so-called documentation. To say it one more time: I was unable to use the official Markdown documentation, http://daringfireball.net/projects/markdown/syntax, to guide the construction of a parser. For example, br is a valid URL enclosed in . . ., so is it a link, as the Automatic Links section would suggest, or is it embedded HTML, as the Inline HTML section would suggest? Can you tell *from the documentation*? For another example, is *foo**bar**ugh* supposed to map to emfoostrongbar/strongugh/em or to emfoo/emembar/ememugh/em? Again, I'm not asking what does this or that *program* do, I'm asking can you tell from the documentation what they *ought* to do? If there is an unambiguous specification of Markdown somewhere (specification; not program), I would be glad to see it. ___ 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] Error when building executable with profiling enabled
You are using TemplateHaskell (-fth switch) which can be tricky. Please see this documentation on profiling with TH: http://www.haskell.org/ghc/docs/7.6.1/html/users_guide/template-haskell.html#id624714. Other than following the documentation I would recommend using Cabal which handles the necessary flags and double-compilation process itself. Best regards, Krzysztof Skrzętnicki On Fri, Apr 5, 2013 at 4:41 PM, Nikolaos Bezirgiannis bez...@gmail.comwrote: Hello, i have an executable where i want to run profiling on. I do: ghc --make -prof -auto-all -fth Custom.hs but it does not built and the output is: bench\HLogo\Custom\Custom.hs:1:1: Dynamic linking required, but this is a non-standard build (eg. prof). You need to build the program twice: once the normal way, and then in the desired way using -osuf to set the object file suffix. I tried googling on the error with no success. What can I do to compile this file for profiling? Cheers, Nikos ___ 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] Compiled code
They are used: any library installed with e.g. cabal-install is kept around not in source form but with .hi and .o files (and perhaps some metadata as well.) Best regards, Krzysztof Skrzętnicki On Fri, Mar 22, 2013 at 11:04 PM, MigMit miguelim...@yandex.ru wrote: Suppose I compiled some module and kept it's .hi and .o files. Is it possible to use this module in my program if the source code was deleted for some reason? Seems like the answer is yes — by creating a fake .hs file (with no real content) and touch-in .hi and .o files I tricked ghc so that it didn't attempt to recompile the module, so the information in .hi and .o files is sufficient. But ghc insists on having the .hs file around, and I didn't find a way to turn it off. Is there any? Or there is a specific reason not to allow this? ___ 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] How to return a network connection to C
If I understand you correctly you need a StablePtr to your Connection value. Please see: http://www.haskell.org/ghc/docs/latest/html/libraries/base-4.6.0.1/Foreign-StablePtr.html Best regards, Krzysztof Skrzętnicki On Thu, Feb 28, 2013 at 6:31 PM, C K Kashyap ckkash...@gmail.com wrote: I am using http://hackage.haskell.org/package/connection. So I create network connection in Haskell getConnection :: IO Connection I'd like this connection to be returned to C so that subsequent calls from C can send in the connection handle. Regards, Kashyap On Thu, Feb 28, 2013 at 9:04 PM, Niklas Hambüchen m...@nh2.me wrote: What data type are you dealing with exactly? If you have a socket, I guess you can just use it from C (via FFI). PS: By Network.Connection, do you mean http://hackage.haskell.org/package/network-connection-0.1.1 ? Seems deprecated. On 28/02/13 06:14, C K Kashyap wrote: Hi, I am using Network.Connection to connect to gmail in my Haskell module - that's compiled to DLL and invoked from C. I need a mechanism to return the connection handle to C so that it can pass it in the subsequent calls. How can I achieve this? Regards, Kashyap ___ 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] FunPtr to C function with #arguments determined at runtime?
Hi, I think libffi might be the answer here. Please see Hackage and Haskell wiki for details. Cheers, Krzysztof Skrzetnicki 17-02-2013 12:18, Ryan Newton rrnew...@gmail.com napisał(a): Hello cafe, I've been poking around and I haven't seen this addressed anywhere except obliquely in the end of section 8.5.1 of the report, where it says that variable argument C functions aren't supported: http://www.haskell.org/onlinereport/haskell2010/haskellch8.html The scenario is pretty simple. I generate C code at runtime. I compile it to a .so. I know how many arguments it expects (but only at runtime), and I get a FunPtr back from 'dlsym'. How do I call it? I was hoping there would be some Raw lower level FFI layer that I could use to invoke a C function without automagic marshaling and all the other goodness provided by the normal foreign import mechanism. Failing that, will I just have to generate complex wrappers on the C side which I call N times to load up N arguments into some stateful container before finally launching the function? Thanks, -Ryan ___ 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] ifdef based on which OS you're on
Well, for sure you can in define that in .cabal file: if !os(windows) CC-Options: -DWINDOWS or something. See: http://www.haskell.org/cabal/users-guide/developing-packages.html#configurations On Fri, Feb 15, 2013 at 3:05 PM, Andrew Cowie and...@operationaldynamics.com wrote: I've got a piece of code that looks like this: baselineContextSSL :: IO SSLContext baselineContextSSL = do ctx - SSL.context SSL.contextSetDefaultCiphers ctx #if defined __MACOSX__ SSL.contextSetVerificationMode ctx SSL.VerifyNone #elif defined __WIN32__ SSL.contextSetVerificationMode ctx SSL.VerifyNone #else SSL.contextSetCADirectory ctx /etc/ssl/certs SSL.contextSetVerificationMode ctx $ SSL.VerifyPeer True True Nothing #endif return ctx all very nice (this being necessary because apparently the non-free operating systems don't store their certs in a reliably discoverable place; bummer). That, however, is not the problem. After all, this sort of thing is what #ifdefs are for. The problem is needing to get an appropriate symbol based on what OS you're using defined. I naively assumed there would be __LINUX__ and __MACOSX__ and __WIN32__ defined by GHC because, well, that's just the sort of wishful thinking that powers the universe. So my question is: what's an appropriate Haskell mechanism for building code that is OS / arch / distro specific? It's not like I have autoconf running generating me a config.h I could #include, right? This feels simple and an appropriate use of CPP; even the symbol names look just about like what I would have expected; stackoverflow said so, must be true. Just need to get the right symbol defined at build time. Any suggestions? AfC Sydney ___ 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] Teaching haskell and fuzzy logic to high school students
You can get the paper here for free: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.40.1464 On Thu, Jan 31, 2013 at 12:02 PM, claudio wbig...@gmail.com wrote: I'm an Italian IT teacher and I would like to introduce functional programming using haskell. As classroom activity, I would like to build-up a simple fuzzy inference engine. Does anyone know if someone has experience in teaching haskell to high school students or something has already been done with fuzzy logic and haskell? I found only this page: http://www.haskell.org/haskellwiki/AI/Logic/Fuzzy with some information and a link to a pubblication (with fee, I didn't download yet). Thanks Claudio ___ 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] ANN: wizards-1.0: A High level, generic library for interrogative user interfaces
Hello, This library looks very nice. Thank you for realeasing it! I realise it took quite an effort to write it. Looking from examples on Github I noticed that you use -XOverlappingInstances. Why do you need such extension? Best regards, Krzysztof Skrzętnicki On Sun, Jul 1, 2012 at 10:17 AM, Liam O'Connor lia...@cse.unsw.edu.auwrote: Hi all, wizards is an Haskell library designed for the quick and painless development of interrogative programs, which revolve around a dialogue with the user, who is asked a series of questions in a sequence much like an installation wizard. Everything from interactive system scripts, to installation wizards, to full-blown shells can be implemented with the support of wizards. It is developed transparently on top of a free monad (see Swierstra's excellent paper on this topic at http://www.cs.ru.nl/~W.Swierstra/Publications/DataTypesALaCarte.pdf), which separates out the semantics of the program from the wizards interface. A variety of backends exist, including a full featured backend for Haskeline, a debug-friendly simpler implementation in terms of System.IO primitives, and a completely pure implementation modelled as a function from an input string to output. It is also possible to write your own backends, or extend the existing back-ends with new features. While both built-in IO backends operate on a console, there is no reason why wizards cannot also be used for making GUI wizard interfaces. The library is highly extensible - back-ends can be written or extended with the type system helpfully tracking what features are supported by which back-ends. Installation instructions and some educational examples are at the github page: https://github.com/liamoc/wizards Information on how to write backends or extend backends, as well as structured API documentation is available on Hackage: http://hackage.haskell.org/package/wizards (Or, you can just run cabal haddock to generate the documentation from the source). Regards, Liam O'Connor ___ 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] Data.Bitmap, readBitmap exception
That bitmap must be pretty weird. 'file' command reports 'data', so headers must be off. Image viewer OTOH does handle the file. Best regards, Krzysztof Skrzętnicki On Thu, Jun 28, 2012 at 2:03 PM, Brandon Allbery allber...@gmail.comwrote: On Thu, Jun 28, 2012 at 7:34 AM, Alexander Foremny alexanderfore...@gmail.com wrote: I am using bitmap-0.2 [1] to load a Bitmap file [2]. However, the following sample GHCi session fails for me. For what it's worth, my system doesn't recognize your bitmap as a valid image file. -- brandon s allbery allber...@gmail.com wandering unix systems administrator (available) (412) 475-9364 vm/sms ___ 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] Hackage 2 maintainership
Hi, Are there any news how things are going? What remains there to be done to get us to Hackage 2? I found this list of tickets: https://github.com/haskell/cabal/issues?labels=hackage2page=1state=open Is there anything more to be done? Best regards, Krzysztof Skrzętnicki On Tue, Feb 14, 2012 at 12:44 AM, Ben Gamari bgamari.f...@gmail.com wrote: Hey all, Those of you who follow the Haskell subreddit no doubt saw today's post regarding the status of Hackage 2. As has been said many times in the past, the primary blocker at this point to the adoption of Hackage 2 appears to be the lack of an administrator. It seems to me this is a poor reason for this effort to be held up. Having taken a bit of time to consider, I would be willing to put in some effort to get things moving and would be willing to maintain the haskell.org Hackage 2.0 instance going forward if necessary. I currently have a running installation on my personal machine and things seem to be working as they should. On the whole, installation was quite trivial, so it seems likely that the project is indeed at a point where it can take real use (although a logout option in the web interface would make testing a bit easier). That being said, it would in my opinion be silly to proceed without fixing the Hackage trac. It was taken down earlier this year due to spamming[1] and it seems the recovery project has been orphaned. I would be willing to help with this effort, but it seems like the someone more familiar with the haskel.org infrastructure might be better equipped to handle the situation. It seems that this process will go something like this, 1) Bring Hackage trac back from the dead 2) Bring up a Hackage 2 instance along-side the existing hackage.haskell.org 3) Enlist testers 4) Let things simmer for a few weeks/months ensuring nothing explodes 5) After it's agreed that things are stable, eventually swap the Hackage 1 and 2 instances This will surely be a non-trivial process but I would be willing to move things forward. Cheers, - Ben [1] http://www.haskell.org/pipermail/cabal-devel/2012-January/008427.html ___ 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] [Haskell] JustHub 'Sherkin' Release
To be honest I did try to use Nix for exactly this purpose. For some reason things started to break and since I couldnt find any documentation on how to do stuff with it, I just abandonded the idea. Also tried out NixOS: pretty much the same story. Everything appears to be fine at the start, but then after few upgrades things start to fail. I know its very vague but really this is how I remember this experience. For one thing there was lack of how tos related to Haskell stuff anywhere. Just some general documentation that really have some gaps. You end up digging up some implementation details just because you wanted to install a new package. I'm not trying to spread FUD: only telling my not-so-success story with Nix. I'm sure Nix/NixOS has some potential but clearly it's not there yet for some reason. Best regards, Krzysztof Skrzętnicki On Fri, Jun 15, 2012 at 9:10 PM, Peter Simons sim...@cryp.to wrote: Hi Chris, I cannot see how it can address any of the user-level Haskell package database management and sandboxing mechanisms that I mentioned in the announcement and subsequent emails. have you ever actually used Nix? Take care, Peter ___ 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] Data.Bitmap question
There is module with a set of unsafeFoo functions here: http://hackage.haskell.org/packages/archive/bitmap/0.0.2/doc/html/Data-Bitmap-Pure-Pixels.html I guess you can use them, but I haven't personally used it. I have, with great success, used different package: JuicyPixels (here: http://hackage.haskell.org/package/JuicyPixels). Best regards, Krzysztof Skrzętnicki On Thu, Jun 7, 2012 at 2:59 PM, Anders Lyckegaard anders.lyckega...@gmail.com wrote: Hi, I have a short question on using Data.Bitmap. I have imported an image using STB-image. img - loadImage filename Now I get img which is a Bitmap data structure. How do I access individual pixels? Thank you in advance, Anders ___ 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] Google Summer of Code - Lock-free data
Hi, I was interested in Distruptor few months ago and started to write a Haskell implementation. Soon I discovered the lack of native CAS operations and abandoned project for a while. I don't really have time to develop it further right now, but the code is available: https://github.com/Tener/disruptor-hs The code as it is now is mostly benchmarking code. I think it is worth trying out. You mention benchmarking TChans: one particular problem with TChans and Chans is that they are unbounded. If the producers outpace consumers it soon ends with memory exhaustion. In the process of writing above code I discovered particularly simple data structure that performs suprisingly well (full implementation: https://github.com/Tener/disruptor-hs/blob/master/Test/ManyQueue.hs) : type Queue a = [MVar a] mkQueue size = cycle `fmap` (replicateM size newEmptyMVar) The throutput is very high, it is bounded and scales well with the number of producer/consumers threads. In the presence of multiple consumers/producers it's not a FIFO queue though, but rather a kind of buffer with funny ordering. Best regards, Krzysztof Skrzętnicki On Fri, Mar 30, 2012 at 00:03, John Lato jwl...@gmail.com wrote: Slightly related: I think it would be interesting to compare a Disruptor-based concurrency communications mechanism and compare it to e.g. TChans 1. Disruptor - http://code.google.com/p/disruptor/ From: Ryan Newton rrnew...@gmail.com I think so. Atomically reading and writing a single memory location (which CAS does) is just a very simple transaction. But using a CAS instruction should be more efficient, since STM has to maintain a transaction log and commit transactions, which creates some overhead. Ah, I see. In that case, it may be worthwhile to implement the CAS instruction in terms of STM as well and measure the performance difference this makes for the final data structure. After all, STM is a lot more compositional than CAS, so I'd like to know whether the loss of expressiveness is worth the gain in performance. There's one annoying hitch with doing apples-to-apples comparisons here. The problem is that CAS falls short of being a hardware-accelerated version of a simple transaction (read TVar, (==) against expected value, conditionally update TVar), because CAS is based on pointer equality rather than true equality. (eq? rather than equal? for any Schemers out there.) For this reason our Fake version of CAS -- for older GHCs and for performance comparison -- has to use reallyUnsafePointerEquality#: http://hackage.haskell.org/packages/archive/IORefCAS/0.2/doc/html/Data-CAS-Internal-Fake.html But we do provide a CASable type class in that package which is precisely for comparing the performance of: - Hardware CAS - Fake CAS -- atomicModifyIORef + ptrEquality - Foreign CAS -- gcc intrinsic + function call ___ 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] Increase GHC stack size?
No, you supply -rtsopts along with --make. Actually --make is just a shorthand for a few other options, you can see which with --verbose. See the documentation too. One important thing though: very often stack overflows come from bad code. See the wiki for more info: http://www.haskell.org/haskellwiki/Stack_overflow Best regards, Krzysztof Skrzętnicki On Sun, Feb 5, 2012 at 20:50, Michael Rice limitc...@gmail.com wrote: I'm using ghc --make... -rtsopts seems to be a link directive. The GHC docs seem to be project oriented. What's the two step process to compile and link a simple .hs file? ghc source.hs (to compile) link step? Michael On Sun, Feb 5, 2012 at 2:21 PM, Mathijs Kwik math...@bluescreen303.nlwrote: ./myProgram +RTS -K1600 If that gives an error, you're program was probably compiled without support for setting RTS options from the command line. Recompile with -rtsopts. Then the above should work On Sun, Feb 5, 2012 at 8:16 PM, Michael Rice limitc...@gmail.com wrote: Stack space overflow: current size 8388608 bytes. Use `+RTS -Ksize -RTS' to increase it. == Couldn't find much on the man or info pages. Example please, say double it (1600) for starters. Michael ___ 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] Serialize instance for System.Posix.Files.FileStatus
I assume you speak about Serialize typeclass from cereal package and FileStatus from unix package. There are several problems with implementing such instance: - FileStatus doesn't export the fact it's a newtype around Ptr CStat - CStat isn't exported either - there are no constructors for FileStatus or any way to change the value of it - it could be implemented internally in unix but then it would have to depend on cereal which is non-trivial change So implementing such instance would basically mean heavy changes to unix package. My advice: implement your own datatype with information equivalent to FileStatus, say FileStatusData, along with function mkFileStatusData :: FileStatus - FileStatusData and provide instance for Serialize for FileStatusData. As for efficiency: I'm not sure it can be done in any better way. In particular you can't be sure that on the system on which you are going to deserialize the value the CStat structure has the same memory layout. So you have to use proper serialization on Haskell side to achieve correctness. Best regards, Krzysztof Skrzętnicki On Wed, Feb 1, 2012 at 15:02, Johan Brinch brin...@gmail.com wrote: Are there plans on implementing an efficient Serialize instance of the FileStatus type? I'm aware that it's just a wrapper around a C stat structure, and I reckon it can be done more efficiently than copying from C to Haskell for every value. -- Johan Brinch ___ 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] Efficient temporary file storage??
From my experience I can recommend msgpack ( http://hackage.haskell.org/package/msgpack) as being extremely fast. It comes with optimized prepared instances for common data structures which is very nice, because you don't have to roll your own version with library like cereal (which is indeed very fast, but simply less convenient). Best regards, Krzysztof Skrzętnicki On Tue, Jan 24, 2012 at 00:37, Nick Rudnick nick.rudn...@googlemail.comwrote: Dear all, if you want to temporarily store haskell data in a file – do you have a special way to get it done efficiently? In an offline, standalone app, I am continuously reusing data volumes of about 200MB, representing Map like tables of a rather simple structure, key: (Int,Int,Int) value: [((Int,Int),LinkId)] which take quite a good deal of time to produce. Is there a recommendation about how to 'park' such data tables most efficiently in files – any format acceptable, quick loading time is the most desirable thing. Thanks a lot in advance, Nick ___ 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] Poll: Do you want a mascot? -- please stop this
I second this. One way is to use Forms from Google Docs. 1. They have been used with success before for similar pools 2. Can provide more elaborate questions 3. Automatically put results into a spreadsheet, which is useful 4. Protect against double-voters (sort of) 5. No spam Best regards, Krzysztof Skrzętnicki On Wed, Nov 23, 2011 at 21:25, Giovanni Tirloni gtirl...@sysdroid.comwrote: On Wed, Nov 23, 2011 at 5:52 PM, heathmatlock heathmatl...@gmail.comwrote: On Wed, Nov 23, 2011 at 1:40 PM, Alexander Bernauer alex-hask...@copton.net wrote: Yes PS: Why not using Doodle for the poll? Email is an easy way to make sure nobody votes twice. 1. It's unlikely to get feedback from the larger Haskell community 2. It floods people with email they don't care (unless they care to keep track of the results) 3. One can just as easily create throw-away emails, subscribe to the list and answer the poll 4. etc... My suggestion is to create a poll somewhere else and let it run for at least a month. Or a more elaborated survey with additional questions trying to capture the community's feeling toward a masket and what kind. I don't think we are in a hurry to get a mascot here so let's take the time and do it properly. -- Giovanni ___ 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] Yesod 0.7.1 using GHC 7.0.2 on Arch Linux
You can also download binary tarball, untar, ./configure --prefix=$HOME/ghc-7.0.2, make install, export PATH=$PATH:$HOME/ghc-7.0.2 and you will be good to go. Best regards, Krzysztof Skrzętnicki On Mon, Mar 14, 2011 at 02:15, Ertugrul Soeylemez e...@ertes.de wrote: I know, but at least I can go on with development. I hope, the problem will be fixed soon. vagif.ve...@gmail.com wrote: No, it is not solved. With -fproduction flag you are loosing devel-server functionality. On Saturday, March 12, 2011 02:45:11 PM Ertugrul Soeylemez wrote: Oh, I just noticed the other thread about this issue. Compiling Yesod with the -fproduction flag solved it. Thanks to Michael for that. Greets, Ertugrul Ertugrul Soeylemez e...@ertes.de wrote: Hello Ryan, thanks a lot. Is there a workaround for this, until it's fixed? Greets, Ertugrul Ryan Yates fryguy...@gmail.com wrote: Looks to be reported here: http://hackage.haskell.org/trac/ghc/ticket/5004 http://hackage.haskell.org/trac/ghc/ticket/5004Ryan On Sat, Mar 12, 2011 at 3:26 PM, Ertugrul Soeylemez e...@ertes.de wrote: Hello there, today I have upgraded to GHC 7.0.2 by doing a system update on my Arch Linux box (x86, 32 bits), and I'm having difficulties to install Yesod. Its dependencies seem to have been installed without problems, but the Yesod package itself fails. The complete build log follows: % cabal install yesod Resolving dependencies... Configuring yesod-0.7.1... Preprocessing library yesod-0.7.1... Preprocessing executables for yesod-0.7.1... Building yesod-0.7.1... [1 of 1] Compiling Yesod( Yesod.hs, dist/build/Yesod.o ) Registering yesod-0.7.1... [1 of 2] Compiling CodeGen ( CodeGen.hs, dist/build/yesod/yesod-tmp/CodeGen.o ) [2 of 2] Compiling Main ( scaffold.hs, dist/build/yesod/yesod-tmp/Main.o ) Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. Loading package bytestring-0.9.1.10 ... linking ... done. Loading package base64-bytestring-0.1.0.2 ... linking ... done. Loading package array-0.3.0.2 ... linking ... done. Loading package containers-0.4.0.0 ... linking ... done. Loading package cereal-0.3.0.0 ... linking ... done. Loading package filepath-1.2.0.0 ... linking ... done. Loading package old-locale-1.0.0.2 ... linking ... done. Loading package old-time-1.0.0.6 ... linking ... done. Loading package unix-2.4.2.0 ... linking ... done. Loading package directory-1.1.0.0 ... linking ... done. Loading package binary-0.5.0.2 ... linking ... done. Loading package data-default-0.2.0.1 ... linking ... done. Loading package tagged-0.2 ... linking ... done. Loading package crypto-api-0.5.2 ... linking ... done. Loading package pureMD5-2.1.0.3 ... linking ... done. Loading package pretty-1.0.1.2 ... linking ... done. Loading package template-haskell ... linking ... done. Loading package transformers-0.2.2.0 ... linking ... done. Loading package deepseq-1.1.0.2 ... linking ... done. Loading package text-0.11.0.5 ... linking ... done. Loading package blaze-builder-0.2.1.4 ... linking ... done. Loading package blaze-html-0.4.1.0 ... linking ... done. Loading package file-embed-0.0.3.1 ... linking ... done. Loading package time-1.2.0.3 ... linking ... done. Loading package unix-compat-0.2.1.1 ... linking ... done. Loading package enumerator-0.4.7 ... linking ... done. Loading package mtl-2.0.1.0 ... linking ... done. Loading package parsec-3.1.1 ... linking ... done. Loading package network-2.2.1.10 ... linking ... done. Loading package wai-0.3.2 ... linking ... done. Loading package utf8-string-0.3.6 ... linking ... done. Loading package web-routes-0.23.4 ... linking ... done. Loading package wai-app-static-0.0.1.1 ... linking ... done. Loading package random-1.0.0.3 ... linking ... done. Loading package clientsession-0.4.1 ... linking ... done. Loading package cookie-0.0.0 ... linking ... done. Loading package failure-0.1.0.1 ... linking ... done. Loading package extensible-exceptions-0.1.1.2 ... linking ... done. Loading package QuickCheck-2.4.0.1 ... linking ... done. Loading package blaze-builder-enumerator-0.2.0.1 ... linking ... done. Loading package json-types-0.1 ... linking ... done. Loading package json-enumerator-0.0.1 ... linking
[Haskell-cafe] Possible bug in Control.Concurrent
Hello Cafe, Here is a simple program that yields strange results: module Main where import Control.Concurrent import Control.Concurrent.Chan import Control.Monad main = do c - newChan writeChan c 1 forkIO $ forever $ do i - readChan c print (forkio,i) isEmptyChan c = print First of all, if we try to run it via runhaskell, it will hang: runhaskell deadlock.hs (forkio,1) -- no more output -- Compiled version OTOH behaves differently dependent on compilation flags. Without -threaded: ./deadlock (forkio,1) False With -threaded: ./deadlock False Now, this is strange thing: we put single element into the channel. We take it out. And then we see the channel isn't really empty. Perhaps there is a race condition here? So we put an delay, so that we will be sure the check for empty channel occurs 1 second later than the channel is emptied. import Control.Concurrent import Control.Concurrent.Chan import Control.Monad main = do c - newChan writeChan c 1 forkIO $ forever $ do i - readChan c print (forkio,i) threadDelay 100 isEmptyChan c = print This program will misbehave. Invariably of -threaded flag it will go like this: ./deadlock (forkio,1) deadlock: thread blocked indefinitely in an MVar operation I have no idea what is the problem here. Perhaps I'm not using the library in the right way. Does anyone has any idea what's going on here? Best regards, Krzysztof Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Possible bug in Control.Concurrent
Shame on me, I forgot to include the software versions I use: $ ghc --version The Glorious Glasgow Haskell Compilation System, version 6.12.3 $ uname -a Linux raptor 2.6.37-ARCH #1 SMP PREEMPT Sat Jan 29 20:00:33 CET 2011 x86_64 Intel(R) Core(TM) i7 CPU 870 @ 2.93GHz GenuineIntel GNU/Linux This is a normal Arch Linux setup with GHC installed via pacman. Best regards, Krzysztof Skrzętnicki 2011/2/9 Krzysztof Skrzętnicki gte...@gmail.com Hello Cafe, Here is a simple program that yields strange results: module Main where import Control.Concurrent import Control.Concurrent.Chan import Control.Monad main = do c - newChan writeChan c 1 forkIO $ forever $ do i - readChan c print (forkio,i) isEmptyChan c = print First of all, if we try to run it via runhaskell, it will hang: runhaskell deadlock.hs (forkio,1) -- no more output -- Compiled version OTOH behaves differently dependent on compilation flags. Without -threaded: ./deadlock (forkio,1) False With -threaded: ./deadlock False Now, this is strange thing: we put single element into the channel. We take it out. And then we see the channel isn't really empty. Perhaps there is a race condition here? So we put an delay, so that we will be sure the check for empty channel occurs 1 second later than the channel is emptied. import Control.Concurrent import Control.Concurrent.Chan import Control.Monad main = do c - newChan writeChan c 1 forkIO $ forever $ do i - readChan c print (forkio,i) threadDelay 100 isEmptyChan c = print This program will misbehave. Invariably of -threaded flag it will go like this: ./deadlock (forkio,1) deadlock: thread blocked indefinitely in an MVar operation I have no idea what is the problem here. Perhaps I'm not using the library in the right way. Does anyone has any idea what's going on here? Best regards, Krzysztof Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Review request for platform independent interactive graphics with VNC
One thing to notice: $ cabal install network-server is needed. Best regards, Krzysztof Skrzętnicki On Thu, Feb 3, 2011 at 12:15, C K Kashyap ckkash...@gmail.com wrote: Hi, I've been working on a Haskell based platform independent graphics rendering using VNC. I'd like it very much if you could take a look at it and give me feedback. Using it is straight forward - git clone g...@github.com:ckkashyap/Chitra.git cd Chitra make ./Main 100 100 5900 Main starts off a vncserver listening on port 5900. A standard vncviewer can be used to connect to 'localhost' and you can see a 100 x 100 screen. Clicking on the screen will set the pixel on the click location. What I eventually want to do is somehow integrate this piece with GHCI in such a manner that one can use GHCI to draw things on the VNC buffer. Regards, Kashyap ___ 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] Packages all screwed up
This is the easiest way conceptually. You can also try to --reinstall every package that 'ghc-pkg check' report is broken. If you pick up the right version and compilation options will match there is a high chance you can fix this state. I've done this before and it worked. Best regards, Krzysztof Skrzętnicki On Tue, Feb 1, 2011 at 08:16, Arnaud Bailly arnaud.oq...@gmail.com wrote: Hi, Thanks for your answers. I did cabal upgrade yesod As for the user/global issue, I think I tried a user install, this is default isn't it? Looks like I will have to reinstall everything :-( Arnaud On Tue, Feb 1, 2011 at 1:34 AM, Antoine Latter aslat...@gmail.com wrote: On Mon, Jan 31, 2011 at 4:59 PM, Arnaud Bailly arnaud.oq...@gmail.com wrote: Hello, I recently tried to upgrade some package (eg. yesod) and it seems that, in the process, I screwed up my Haskell packages setup. When I am trying to do a simple: ghc --make Crete1941 What command(s) did you issue to upgrade some packages? Were you trying to do a user or global install? When ghc loads packages, I've had cases where packages in the user db would shadow packages in the global db, causing *other* packages in the global db to report as broken. Thanks, Antoine ___ 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] Packages all screwed up
AFAIK GHC on Windows comes with it's own mingw, but I'm not sure if the toolchain is complete. But I wouldn't try to reinstall core packages anyway. They are best picked from installation package. Best regards, Krzysztof Skrzętnicki 2011/2/1 Arnaud Bailly arnaud.oq...@gmail.com I started that way but quickly ran into issues about compilers toolchain for certain packages: I am on windows and some core packages require mingw toolchain. 2011/2/1 Krzysztof Skrzętnicki gte...@gmail.com: This is the easiest way conceptually. You can also try to --reinstall every package that 'ghc-pkg check' report is broken. If you pick up the right version and compilation options will match there is a high chance you can fix this state. I've done this before and it worked. Best regards, Krzysztof Skrzętnicki On Tue, Feb 1, 2011 at 08:16, Arnaud Bailly arnaud.oq...@gmail.com wrote: Hi, Thanks for your answers. I did cabal upgrade yesod As for the user/global issue, I think I tried a user install, this is default isn't it? Looks like I will have to reinstall everything :-( Arnaud On Tue, Feb 1, 2011 at 1:34 AM, Antoine Latter aslat...@gmail.com wrote: On Mon, Jan 31, 2011 at 4:59 PM, Arnaud Bailly arnaud.oq...@gmail.com wrote: Hello, I recently tried to upgrade some package (eg. yesod) and it seems that, in the process, I screwed up my Haskell packages setup. When I am trying to do a simple: ghc --make Crete1941 What command(s) did you issue to upgrade some packages? Were you trying to do a user or global install? When ghc loads packages, I've had cases where packages in the user db would shadow packages in the global db, causing *other* packages in the global db to report as broken. Thanks, Antoine ___ 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] Behaviour of System.Directory.getModificationTime
If this is not a toy program I would really suggest using something that is builtin in the OS of choice. On Linux there is inotify ( http://en.wikipedia.org/wiki/Inotify), but I'm pretty sure that other OSes have similar interfaces. The modification time method seems really fragile and I probably not very efficient as well. Best regards, Krzysztof Skrzętnicki On Thu, Dec 16, 2010 at 17:50, Arnaud Bailly arnaud.oq...@gmail.com wrote: actually, IRL the code works as expected. Might it be possible that the speed of test execution is greater than the granularity of the system's modification timestamp? ___ 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] ANN: mute-unmute-0.2.0.0
*
Hello!
I'm pleased to announce a small utility program I wrote recently. Today I
pushed version 0.2.0.0 of mute-unmute to Hackage, from with you can
cabal-install it right now (following the usual 'update' step). What it
does? It's simple: it will mute the sound when you lock your screen and
unmute it back again when you unlock it.
Why anyone would need such program? Well, this is a little bit
more complicated.
I work in open space kind of office. It can get quite noisy there. I often
sit with headphones on, but when I walk away from my desk I put them down
and lock my screen. Here comes uncomfortable moment: when I remove my
headphones suddenly people around me who doesn't use their headphones now
start to hear the music I listen to. And they don't always like it, so I
manually mute the sound to make happy.
But now, instead of doing this task by hand I have a program do it for me
:-)
Unfortunately this kind of programs tend to be pretty much platform
specific. Current version supports the recent versions of Gnome and KDE, but
needs ALSA. It's quite common setup, but if you happen to have a different
one you can easily hack the code (it's very straightforward) and send me
patches. Patches are always welcome. The source repo is on Github and
released versions are on Hackage:
Github:
http://github.com/Tener/mute-unmute http://github.com/Tener/mute-unmute#
Hackage:
http://hackage.haskell.org/package/mute-unmute
Example use:
~/ mute-unmute # first session, it will ask for configuration options
mute-unmute: Creating config directory...
mute-unmute: Mute config is missing...
Mute sound card and press RETURN
mute-unmute: Unmute config is missing...
Unmute sound card and press RETURN
mute-unmute: Session: UnixAbstract {addrPath = /tmp/dbus-1tB1AEUcgg,
addrGuid = Just 19ec85e3778816ad38a77bbf003f}
mute-unmute: Connected
mute-unmute: Handler added: [MatchType Signal,MatchInterface
org.gnome.ScreenSaver,MatchMember ActiveChanged,MatchPath
/org/gnome/ScreenSaver]
mute-unmute: Handler added: [MatchType Signal,MatchInterface
org.freedesktop.ScreenSaver,MatchMember ActiveChanged,MatchPath
/ScreenSaver]
^C
~/ mute-unmute # remembers previous options which can be changed by calling
with --store switch
mute-unmute: Session: UnixAbstract {addrPath = /tmp/dbus-1tB1AEUcgg,
addrGuid = Just 19ec85e3778816ad38a77bbf003f}
mute-unmute: Connected
mute-unmute: Handler added: [MatchType Signal,MatchInterface
org.gnome.ScreenSaver,MatchMember ActiveChanged,MatchPath
/org/gnome/ScreenSaver]
mute-unmute: Handler added: [MatchType Signal,MatchInterface
org.freedesktop.ScreenSaver,MatchMember ActiveChanged,MatchPath
/ScreenSaver]
mute-unmute: Message {mType = Signal, mFlags = [NoReplyExpected], mSerial =
31, mPath = Just /org/gnome/ScreenSaver, mInterface = Just
org.gnome.ScreenSaver, mMember = Just ActiveChanged, mErrorName =
Nothing, mReplySerial = Nothing, mDestination = Nothing, mSender = Just
:1.19, mBody = [Variant (True) {- b -}]}
mute-unmute: Lock screen
mute-unmute: Message {mType = Signal, mFlags = [NoReplyExpected], mSerial =
32, mPath = Just /org/gnome/ScreenSaver, mInterface = Just
org.gnome.ScreenSaver, mMember = Just ActiveChanged, mErrorName =
Nothing, mReplySerial = Nothing, mDestination = Nothing, mSender = Just
:1.19, mBody = [Variant (False) {- b -}]}
mute-unmute: Unlock screen
^C
*
You can get usage information with --help switch:
*~/ mute-unmute --help
*mute-unmute
--store ask for mute and unmute configurations
--store-muteask for mute configuration
--store-unmute ask for unmute configuration
-d --daemonwait for screensaver state changes
-h, -? --help show help
There isn't much more I can say. I hope you find the program at least
educational (as a simple example of DBus usage) if not useful.
Best regards,
Krzysztof Skrzętnicki
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Re: [Haskell-cafe] Installing encoding package from Hackage
I was able to build encoding-0.6.2. My steps: (0. Update package list with 'cabal update') 1. Unpack package with 'cabal unpack encoding' 2. Edit encoding.cabal. We need to add HaXml as dependency. It should be added to 'Build-Depends' field. I've added below HaXml == 1.20.2 because 1.20.2. is the latest version available at the time of writing. Library if flag(splitBase) if flag(newGHC) Build-Depends:bytestring, base = 3 5, binary, mtl, containers, extensible-exceptions, array, template-haskell, regex-compat, ghc-prim, ghc = 6.10, HaXml == 1.20.2 else Build-Depends:bytestring, base = 3 5, binary, mtl, containers, extensible-exceptions, array, template-haskell, regex-compat, ghc 6.10, HaXml == 1.20.2 else Build-Depends: base 3, binary, extensible-exceptions, template-haskell 3. Instal with cabal install run in the directory next to encoding.cabal. It looks like package maintainer forgot to specify this dependency. Best regards Krzysztof Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] ANN: readline-statevar-1.0.1.0
Hello I am happy to announce a release of small package called readline-statevar. It's a small wrapping library around readline, which in turn wraps libreadline. The reason I wrote it is because I wasn't happy with the API of readline. It was composed of tons of functions like setX/getX, where there could be just one StateVar instead, yielding OpenGL-kind API. This version aims to match readline-1.0.1.0. (Hence the version number chosen). I wrote it mostly manually, with a little help from my emacs-fu, so there is a chance I missed a thing or two. There is git repo available [1], along with issue tracker [2] and Hackage page [3]. Feel encouraged to: cabal update cabal install readline-statevar And give it a try! Best regards Krzysztof Skrzętnicki [1] http://github.com/Tener/haskell-readline-statevar/ [2] http://github.com/Tener/haskell-readline-statevar/issues [3] http://hackage.haskell.org/package/readline-statevar ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] ANN: package-vt-0.1.3.3, Haskell Package Versioning Tool
Hi!
I'm pleased to announce the first release of my program package-vt. It's
role is to detect changes between two versions of package that should cause
version bump.
Recommended versioning policy for Haskell packages is on the wiki [1].
The ultimate goal is to get as good approximation of the algorithm specified
there as possible. Currently the tool is far from being complete: it only
detects changes to exports in .cabal and module files, but doesn't take any
types into consideration, not to mention other possible heuristics.
This tool is not meant as a replacement for developer's own brain. It can
only detect a subset of changes, and there will always be some important
changes it won't catch, like adding such line:
head (_:y:_) = y
However, it can be used for some quality checks.
Thing that needs improving is user interface. No options are currently
accepted. This, and a lot more, will change in future versions.
You can find a Git repo here [2]. The repo contains 'tests' directory with
two useful scripts. You can use them to run package-vt on anything from
Hackage.
Here are a few random usage examples:
1) Detect small change within module
package-vt packages/HCL/1.1/HCL-1.1/HCL.cabal
packages/HCL/1.2/HCL-1.2/HCL.cabal
Single changes:
ChangeABC : Entity added to module ModuleName HCL
---
EVar (UnQual (Ident prompt1))
---
Biggest change comes from:
ChangeABC : Entity added to module ModuleName HCL
---
EVar (UnQual (Ident prompt1))
2) Detect new module added to .cabal
package-vt 0.2.0/AERN-Net-0.2.0/AERN-Net.cabal
0.2.1/AERN-Net-0.2.1/AERN-Net.cabal
Single changes:
ChangeABC : Entity added to module ModuleName
Control.ERNet.Foundations.Process
---
EThingAll (UnQual (Ident ERProcessAction))
---ChangeABC : Module(s) added.(Consider AB change if new modules are likely
to cause name collisions)
---
Control/ERNet/Blocks/Real/LFT
---
Biggest change comes from:
ChangeABC : Module(s) added.(Consider AB change if new modules are likely to
cause name collisions)
---
Control/ERNet/Blocks/Real/LFT
---
3) Using testing script: package-vt correctly detects that AERN-RnToRM-0.4.9
should rather be 0.5.0 because the module
Data.Number.ER.RnToRm.UnitDom.ChebyshevBase.Polynom.Field
has been removed.
./test-on-package.lhs AERN-RnToRm
--cut--
Testing package-vt on AERN-RnToRm-0.4.2 and AERN-RnToRm-0.4.9
Parse error: VarSym # : SrcLoc {srcFilename =
0.4.2/AERN-RnToRm-0.4.2/src/Data/Number/ER/RnToRm/Approx/DomTransl.hs,
srcLine = 174, srcColumn = 1}
Single changes:
ChangeABC : Entity added to module ModuleName Data.Number.ER.RnToRm.Approx
---
EVar (UnQual (Ident keyPointsConsistencyCheck))
EVar (UnQual (Ident keyPointsPointwiseConsistencyCheck))
---ChangeABC : Entity added to module ModuleName
Data.Number.ER.RnToRm.UnitDom.Approx
---
EVar (UnQual (Ident keyPointsConsistencyCheck))
EVar (UnQual (Ident keyPointsPointwiseConsistencyCheck))
---ChangeAB : Module(s) removed/renamed.
---
Data/Number/ER/RnToRm/UnitDom/ChebyshevBase/Polynom/Field
---
Biggest change comes from:
ChangeAB : Module(s) removed/renamed.
---
Data/Number/ER/RnToRm/UnitDom/ChebyshevBase/Polynom/Field
---
ExitSuccess
--cut--
In case of any trouble please email me or report an issue here [3].
In the near future I'll post more specific plans about development on my
blog [4].
I hope you will find it useful.
Best regards,
Krzysztof Skrzętnicki
[1] http://www.haskell.org/haskellwiki/Package_versioning_policy
[2] http://github.com/Tener/haskell-package-vt
[3] http://github.com/Tener/haskell-package-vt/issues
[4] http://mostlycode.wordpress.com
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Re: [Haskell-cafe] Installing documentation with cabal
It is. From command line: cabal install package --enable-documentation or add line documentation: True to .cabal/config or equivalent. Best regards Krzysztof Skrzętnicki On Tue, Aug 18, 2009 at 22:29, Maciej Piechotka uzytkown...@gmail.comwrote: Is it possible to automatically (or non-automatically) install documentation when installing package with cabal-install? Regards ___ 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] How to know the build dependencies?
If your module compiles, you can get the info by passing '-ddump-types': TYPE SIGNATURES numbersTests :: Test testAverage :: Test testBindInt :: Test TYPE CONSTRUCTORS Dependent modules: [(MoresmauJP.Util.Numbers, False)] Dependent packages: [HUnit-1.2.0.3, base, ghc-prim, integer] It is, however, available only after your code has successfully compiled. Best regards Krzysztof Skrzętnicki On Sun, Jun 14, 2009 at 04:22, Magicloud Magicloudsmagicloud.magiclo...@gmail.com wrote: Hi, I am learning to use cabal for my code. Just when I start, I met a question, is there an easy way to find out what packages my code depends? Thanks. ___ 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] Re: [Haskell] ANNOUNCE: OpenGLRaw 1.0.0.0
On Thu, Jun 11, 2009 at 19:37, Felipe Lessafelipe.le...@gmail.com wrote: On Thu, Jun 11, 2009 at 06:56:01PM +0200, Sven Panne wrote: Version 1.0.0.0 covers the OpenGL 3.1 core, all ARB extensions and all EXT extensions. What about OpenGL 2.1? As I understand, Linux won't have OpenGL 3.0 or 3.1 for at least some months, $ glxinfo | grep 'OpenGL version' OpenGL version string: 2.1 Mesa 7.5-rc3 On my machine I get: $ glxinfo | grep -i version server glx version string: 1.4 client glx version string: 1.4 GLX version: 1.3 OpenGL version string: 3.0.0 NVIDIA 180.51 OpenGL shading language version string: 1.30 NVIDIA via Cg compiler So it doesn't appear to be true. Best regards Krzysztof Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Incremental XML parsing with namespaces?
On Mon, Jun 8, 2009 at 20:39, John Millikinjmilli...@gmail.com wrote:
I'm trying to convert an XML document, incrementally, into a sequence
of XML events. A simple example XML document:
doc xmlns=org:myproject:mainns xmlns:x=org:myproject:otherns
titleDoc title/title
x:refabc1234/x:ref
html xmlns=http://www.w3.org/1999/xhtml;bodyHello world!/body/html
/doc
The document can be very large, and arrives in chunks over a socket,
so I need to be able to feed the text data into a parser and receive
a list of XML events per chunk. Chunks can be separated in time by
intervals of several minutes to an hour, so pausing processing for the
arrival of the entire document is not an option. The type signatures
would be something like:
type Namespace = String
type LocalName = String
data Attribute = Attribute Namespace LocalName String
data XMLEvent =
EventElementBegin Namespace LocalName [Attribute] |
EventElementEnd Namespace LocalName |
EventContent String |
EventError String
parse :: Parser - String - (Parser, [XMLEvent])
I've looked at HaXml, HXT, and hexpat, and unless I'm missing
something, none of them can achieve this:
+ HaXml and hexpat seem to disregard namespaces entirely -- that is,
the root element is parsed to doc instead of
(org:myproject:mainns, doc), and the second child is x:ref
instead of (org:myproject:otherns, ref). Obviously, this makes
parsing mixed-namespace documents effectively impossible. I found an
email from 2004[1] that mentions a filter for namespace support in
HaXml, but no further information and no working code.
I would recommend hexpat to do the job. Contrary to what you are
saying, hexpat does offer namespace handling:
http://hackage.haskell.org/packages/archive/hexpat/0.8/doc/html/Text-XML-Expat-Namespaced.html
Perhaps you need more than that?
Personally I found hexpat to be fast, space efficient and easy to use.
Here is the representation I got for your example. Please note the
namespaces in right places.
* (toNamespaced ( toQualified t'))
Element {eName = NName {nnNamespace = Just org:myproject:mainns,
nnLocalPart = doc}, eAttrs = [(NName {nnNamespace = Just
http://www.w3.org/2000/xmlns/;, nnLocalPart =
x},org:myproject:otherns),(NName {nnNamespace = Just
org:myproject:mainns, nnLocalPart =
xmlns},org:myproject:mainns)], eChildren = [Text \n,Text
,Element {eName = NName {nnNamespace = Just org:myproject:mainns,
nnLocalPart = title}, eAttrs = [], eChildren = [Text Doc
title]},Text \n,Text ,Element {eName = NName {nnNamespace =
Just org:myproject:otherns, nnLocalPart = ref}, eAttrs = [],
eChildren = [Text abc1234]},Text \n,Text ,Element {eName =
NName {nnNamespace = Just http://www.w3.org/1999/xhtml;, nnLocalPart
= html}, eAttrs = [(NName {nnNamespace = Just
http://www.w3.org/1999/xhtml;, nnLocalPart =
xmlns},http://www.w3.org/1999/xhtml;)], eChildren = [Element {eName
= NName {nnNamespace = Just http://www.w3.org/1999/xhtml;,
nnLocalPart = body}, eAttrs = [], eChildren = [Text Hello
world!]}]},Text \n]}
Best regards
Krzysztof Skrzętnicki
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Re: [Haskell-cafe] Incremental XML parsing with namespaces?
And just to provide an example of working program:
---
module Main where
import Text.XML.Expat.Qualified
import Text.XML.Expat.Namespaced
import Text.XML.Expat.Tree
import qualified Data.ByteString.Lazy as BSL
main = do
f - BSL.readFile doc1.xml
let (tree,error) = parseTree Nothing f
case error of
Nothing - putStrLn Here you are: (print . toNamespaced .
toQualified $ (tree :: Node String String))
Just err - putStrLn Error! print err
---
$ ./hexpat-test
Here you are:
Element {eName = NName {nnNamespace = Just org:myproject:mainns,
nnLocalPart = doc}, eAttrs = [(NName {nnNamespace = Just
http://www.w3.org/2000/xmlns/;, nnLocalPart =
x},org:myproject:otherns),(NName {nnNamespace = Just
org:myproject:mainns, nnLocalPart =
xmlns},org:myproject:mainns)], eChildren = [Text \n,Text
,Element {eName = NName {nnNamespace = Just org:myproject:mainns,
nnLocalPart = title}, eAttrs = [], eChildren = [Text Doc
title]},Text \n,Text ,Element {eName = NName {nnNamespace =
Just org:myproject:otherns, nnLocalPart = ref}, eAttrs = [],
eChildren = [Text abc1234]},Text \n,Text ,Element {eName =
NName {nnNamespace = Just http://www.w3.org/1999/xhtml;, nnLocalPart
= html}, eAttrs = [(NName {nnNamespace = Just
http://www.w3.org/1999/xhtml;, nnLocalPart =
xmlns},http://www.w3.org/1999/xhtml;)], eChildren = [Element {eName
= NName {nnNamespace = Just http://www.w3.org/1999/xhtml;,
nnLocalPart = body}, eAttrs = [], eChildren = [Text Hello
world!]}]},Text \n]}
# we mess with doc1.xml and exchange /doc for /do
$ ./hexpat-test
Error!
XMLParseError mismatched tag (XMLParseLocation {xmlLineNumber = 5,
xmlColumnNumber = 2, xmlByteIndex = 205, xmlByteCount = 0})
Best regards
Krzysztof Skrzętnicki
2009/6/9 Krzysztof Skrzętnicki gte...@gmail.com:
On Mon, Jun 8, 2009 at 20:39, John Millikinjmilli...@gmail.com wrote:
I'm trying to convert an XML document, incrementally, into a sequence
of XML events. A simple example XML document:
doc xmlns=org:myproject:mainns xmlns:x=org:myproject:otherns
titleDoc title/title
x:refabc1234/x:ref
html xmlns=http://www.w3.org/1999/xhtml;bodyHello
world!/body/html
/doc
The document can be very large, and arrives in chunks over a socket,
so I need to be able to feed the text data into a parser and receive
a list of XML events per chunk. Chunks can be separated in time by
intervals of several minutes to an hour, so pausing processing for the
arrival of the entire document is not an option. The type signatures
would be something like:
type Namespace = String
type LocalName = String
data Attribute = Attribute Namespace LocalName String
data XMLEvent =
EventElementBegin Namespace LocalName [Attribute] |
EventElementEnd Namespace LocalName |
EventContent String |
EventError String
parse :: Parser - String - (Parser, [XMLEvent])
I've looked at HaXml, HXT, and hexpat, and unless I'm missing
something, none of them can achieve this:
+ HaXml and hexpat seem to disregard namespaces entirely -- that is,
the root element is parsed to doc instead of
(org:myproject:mainns, doc), and the second child is x:ref
instead of (org:myproject:otherns, ref). Obviously, this makes
parsing mixed-namespace documents effectively impossible. I found an
email from 2004[1] that mentions a filter for namespace support in
HaXml, but no further information and no working code.
I would recommend hexpat to do the job. Contrary to what you are
saying, hexpat does offer namespace handling:
http://hackage.haskell.org/packages/archive/hexpat/0.8/doc/html/Text-XML-Expat-Namespaced.html
Perhaps you need more than that?
Personally I found hexpat to be fast, space efficient and easy to use.
Here is the representation I got for your example. Please note the
namespaces in right places.
* (toNamespaced ( toQualified t'))
Element {eName = NName {nnNamespace = Just org:myproject:mainns,
nnLocalPart = doc}, eAttrs = [(NName {nnNamespace = Just
http://www.w3.org/2000/xmlns/;, nnLocalPart =
x},org:myproject:otherns),(NName {nnNamespace = Just
org:myproject:mainns, nnLocalPart =
xmlns},org:myproject:mainns)], eChildren = [Text \n,Text
,Element {eName = NName {nnNamespace = Just org:myproject:mainns,
nnLocalPart = title}, eAttrs = [], eChildren = [Text Doc
title]},Text \n,Text ,Element {eName = NName {nnNamespace =
Just org:myproject:otherns, nnLocalPart = ref}, eAttrs = [],
eChildren = [Text abc1234]},Text \n,Text ,Element {eName =
NName {nnNamespace = Just http://www.w3.org/1999/xhtml;, nnLocalPart
= html}, eAttrs = [(NName {nnNamespace = Just
http://www.w3.org/1999/xhtml;, nnLocalPart =
xmlns},http://www.w3.org/1999/xhtml;)], eChildren = [Element {eName
= NName {nnNamespace = Just http://www.w3.org/1999/xhtml;,
nnLocalPart = body}, eAttrs = [], eChildren = [Text Hello
world!]}]},Text \n]}
Best regards
Krzysztof Skrzętnicki
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Re: [Haskell-cafe] Convert IO Int to Int
On Tue, Jun 9, 2009 at 16:14, Daniel Fischerdaniel.is.fisc...@web.de wrote: Am Dienstag 09 Juni 2009 15:57:24 schrieb Magnus Therning: On Tue, Jun 9, 2009 at 2:52 PM, ptrashptr...@web.de wrote: Hmm...it am not getting through it. I just want to generate a random number and then compare it with other numbers. Something like r = randomRIO (1, 10) if (r 5) then... else ... You have to do it inside the IO monad, something like myFunc = do r - randomRIO (1, 10 if r 5 then ... else ... /M Or make the source of the pseudo-random numbers explicit: import System.Random function :: (RandomGen g, Random a) = g - other args - result function gen whatever | r 5 = blah newgen something | r 3 = blub newgen somethingElse | otherwise = bling where (r,newgen) = randomR (lo,hi) gen and finally, when the programme is run: main = do args - getArgs sg - getStdGen foo - thisNThat print $ function sg foo If you're doing much with random generators, wrap it in a State monad. To avoid reinventing the wheel one can use excellent package available on Hackage: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/MonadRandom The die function simulates the roll of a die, picking a number between 1 and 6, inclusive, and returning it in the Rand monad. Notice that this code will work with any source of random numbers g. die :: (RandomGen g) = Rand g Int die = getRandomR (1,6) The dice function uses replicate and sequence to simulate the roll of n dice. dice :: (RandomGen g) = Int - Rand g [Int] dice n = sequence (replicate n die) To extract a value from the Rand monad, we can can use evalRandIO. main = do values - evalRandIO (dice 2) putStrLn (show values) Best regards Krzysztof Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Random Number
On Sun, Jun 7, 2009 at 21:33, ptrashptr...@web.de wrote: Hi, is the are way (or a build in method) in haskell to get a random number from a number bottom to a number top? Something like let randomNumber = random 1 30 to get a random number between 1 and 30. I don't mean to be rude, but did you even tried to read the documentation? The function you want is here: http://www.haskell.org/ghc/docs/latest/html/libraries/random/System-Random.html Before you ask any other questions please read this essay: http://mattgemmell.com/2008/12/08/what-have-you-tried Best regards Krzysztof Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Stack overflow
On Thu, May 28, 2009 at 14:41, Bertram Felgenhauer bertram.felgenha...@googlemail.com wrote: Krzysztof Skrzętnicki wrote: 2009/5/27 Bertram Felgenhauer bertram.felgenha...@googlemail.com: I wrote: Krzysztof Skrzętnicki wrote: The code for modifying the counter: (\ msg - atomicModifyIORef ioref (\ cnt - (cntMsg cnt msg,( atomicModifyIORef does not force the new value of the IORef. If the previous contents of the IORef is x, the new contents will be a thunk, (\ cnt - (cntMsg cnt msg,())) x Sorry, it's slightly worse than that. The contents becomes sel_0 (\ cnt - (cntMsg cnt msg, ())) x where sel_0 is basically an RTS internal version of fst. Instead of reading the new value of the IORef, you could also force the old one: atomicModifyIORef ioref (\ cnt - (cntMsg cnt msg, msg)) = (return $!) Thanks for the tip, although it seems tricky to get it right. I wonder why there is no strict version of atomicModifyIORef? Something like this? -- | Stricter version of 'atomicModifyIORef', which prevents building -- up huge thunks in the 'IORef' due to repeated modification. -- Unlike 'atomicModifyIORef', 'atomicModifyIORef'' may block. atomicModifyIORef' :: IORef a - (a - (a, b)) - IO b atomicModifyIORef' ioref f = do res - atomicModifyIORef ioref f new - readIORef ioref new `seq` return res (The step that may block is forcing the new value - if another thread is already evaluating part of the thunk, the currently executing thread will block, waiting for the other thread to finish.) Dually there might be a strict version of IORef datatype. One interesting feature of atomicModifyIORef is that its implementation is lock-free, and never blocks (which affects exception handling): replacing the old value by the new value is done with compare-and-swap operation in a tight loop. Each iteration executes very quickly because all it does is replace the reference to the old value in the new thunk. With a strict IORef, the time window between reading the old value and storing the new value would become arbitrarily large, because you'd have to force the new value before exchanging it with the old value. So a reasonable implementation would have to use locks instead, I think, making atomicModifyIORef more expensive, and less useful in contexts that block exceptions. We may as well drop the 'atomic' keyword and provide a warning about possible blocking of thread. The end user may forkIO the modification if he wants to. I modified the code as follows, it works now: (\ msg - atomicModifyIORef ioref (\ cnt - (cntMsg cnt msg,cnt)) = (return $!)) Thank you all for your help! Best regards Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Stack overflow
Hello Cafe I'm currently writing an app with heavy use of message passing. To see which messages takes most of the bandwidth I wrote the following code: -- data Counter = CNT !Int !Int !Int !Int cntMsg (CNT a b c d) (MoveOther _ _) = (CNT a+1 b c d) cntMsg (CNT a b c d) (MoveSelf _) = (CNT a b+1 c d) cntMsg (CNT a b c d) (NilMsg) = (CNT a b c+1 d) cntMsg (CNT a b c d) (RoundEnd) = (CNT a b c d+1) emptyCnt = CNT 0 0 0 0 showCnt (CNT a b c d) = printf CNT MoveOther=%d MoveSelf=%d NilMsg=%d RoundEnd=%d a b c d -- The code for modifying the counter: (\ msg - atomicModifyIORef ioref (\ cnt - (cntMsg cnt msg,( Running it without increased stack blows it. With 200M stack I get after a second or so: CNT MoveOther=2125764 MoveSelf=0 NilMsg=0 RoundEnd=2916 The datatype itself is strict. So where is the thunk actually accumulating? Best regards Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Stack overflow
2009/5/27 Bertram Felgenhauer bertram.felgenha...@googlemail.com: I wrote: Krzysztof Skrzętnicki wrote: The code for modifying the counter: (\ msg - atomicModifyIORef ioref (\ cnt - (cntMsg cnt msg,( atomicModifyIORef does not force the new value of the IORef. If the previous contents of the IORef is x, the new contents will be a thunk, (\ cnt - (cntMsg cnt msg,())) x Sorry, it's slightly worse than that. The contents becomes sel_0 (\ cnt - (cntMsg cnt msg, ())) x where sel_0 is basically an RTS internal version of fst. Instead of reading the new value of the IORef, you could also force the old one: atomicModifyIORef ioref (\ cnt - (cntMsg cnt msg, msg)) = (return $!) Thanks for the tip, although it seems tricky to get it right. I wonder why there is no strict version of atomicModifyIORef? Dually there might be a strict version of IORef datatype. Best regards Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Example code won't compile
The one important line is import Control.Monad.Error It adds dependancy on mtl package, which is not used by default (contrary to 'base' package, which includes Monad, System and IO modules). With --make GHC adds it automatically. Therefore $ ghc -package mtl ex14.hs compiles fine. I'd recommend using --make. In rare occasions when there is a namespace clash between packages one can simply hide offending packages or specify preferred ones. Best regards Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Vector-like data structure
Thank both of you for your responses. Unfortunately I decided to switch to Python for this project, as I plan to use BerkeleyDB and Haskell bindings for it are poorly written. Best regards Christopher Skrzętnicki 2009/5/3 Don Stewart d...@galois.com: gtener: Hi I'm looking for a data structure with following characteristics: 1. O(1) lookup 2. O(1) modification 3. amortized O(1) append 4. O(1) size query This roughly characterizes C++ vector class. I'm ready to implement it myself, but first I would like to ask if anyone knows package with similar data structure. If there are many, which one would you choose and why? A number of the array packages behave like this. The trie packages are O(log(wordsize)), so another option (they tend to have better append complexity as well). -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Vector-like data structure
Hi I'm looking for a data structure with following characteristics: 1. O(1) lookup 2. O(1) modification 3. amortized O(1) append 4. O(1) size query This roughly characterizes C++ vector class. I'm ready to implement it myself, but first I would like to ask if anyone knows package with similar data structure. If there are many, which one would you choose and why? Best regards Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Array Binary IO molecular simulation
On Sat, May 2, 2009 at 11:12, Jason Dusek jason.du...@gmail.com wrote: I believe Data.Binary includes a header with the data it serializes. In consequence, the second and all following arrays will be invisible. [Apologies for Jason for sending this twice to him] I didn't check the Binary instance for arrays, however I belive it's not true. Consider Binary instances for tuples: instance (Binary a, Binary b) = Binary (a,b) where put (a,b) = put a put b get = liftM2 (,) get get instance (Binary a, Binary b, Binary c) = Binary (a,b,c) where put (a,b,c) = put a put b put c get = liftM3 (,,) get get get If what you are saying would be true, the tuple instances would be incorrect for array tuples. Best regards Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Memory usage of cabal install
Jakiej platformy dokładnie dotyczy Twój problem? Proponuję upgrade do najnowszej wersji - można ją ściągnąć ze strony GHC. Pozdrawiam Krzysztof Skrzętnicki 2009/4/27 Krzysztof Kościuszkiewicz k.kosciuszkiew...@gmail.com: Hello Haskell-Café, I have a problem with high memory usage of cabal-install. Whenever I try to install or upgrade a package, cabal manages to consume 1,3G of memory before I killed it (on a 32-bit machine with 1 GB of memory). Increasing verbosity does not help, memory consumption goes up after the message Resolving dependencies... shows up. I use ghc 6.8.2 and cabal-install version 0.5.1 using version 1.4.0.1 of the Cabal library. Is there a workaround? I would like to avoid fetching building packages manually. -- Krzysztof Kościuszkiewicz Simplicity is the ultimate sophistication -- Leonardo da Vinci ___ 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] Binary I/O options
There is already a network-bytestring package: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/network-bytestring Regards Christopher Skrzętnicki On Fri, Apr 24, 2009 at 16:20, David Leimbach leim...@gmail.com wrote: Sounds like the endorsement I was looking for :-) On Fri, Apr 24, 2009 at 7:18 AM, John Van Enk vane...@gmail.com wrote: I use Data.Binary to encode/decode all messages/packets in my P2P VPN application (http://code.google.com/p/scurry/). It's been quite fast and has be suitable for all my needs thus far. On Fri, Apr 24, 2009 at 10:15 AM, David Leimbach leim...@gmail.comwrote: I see that there are a few approaches to doing Binary I/O with Haskell, and the one I'm currently looking at using is Data.Binary from Hackage. I was just wondering what folks were choosing for building networked applications and doing Binary I/O. The approach I was about to take was to use Data.Binary to create ByteString for Network calls with a standard I/O package. Are there other good options? Dave ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- /jve ___ 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] Template Haskell + Profiling
Hi I'm trying to build some modules that use TH with profiling enabled. The normal build works: $ ghc -fforce-recomp --make -cpp -O -DXQUERY2_TEST Main [1 of 8] Compiling Text.XML.Expat.FormatCustom ( Text/XML/Expat/FormatCustom.hs, Text/XML/Expat/FormatCustom.o ) [2 of 8] Compiling DataStructures ( DataStructures.hs, DataStructures.o ) Loading package ghc-prim ... linking ... done. Loading package integer ... linking ... done. Loading package base ... linking ... done. Loading package syb ... linking ... done. Loading package array-0.2.0.0 ... linking ... done. Loading package packedstring-0.1.0.1 ... linking ... done. Loading package containers-0.2.0.1 ... linking ... done. Loading package pretty-1.0.1.0 ... linking ... done. Loading package template-haskell ... linking ... done. Loading package mtl-1.1.0.2 ... linking ... done. Loading package filepath-1.1.0.2 ... linking ... done. Loading package old-locale-1.0.0.1 ... linking ... done. Loading package old-time-1.0.0.2 ... linking ... done. Loading package unix-2.3.2.0 ... linking ... done. Loading package directory-1.0.0.3 ... linking ... done. Loading package process-1.0.1.1 ... linking ... done. Loading package random-1.0.0.1 ... linking ... done. Loading package derive-0.1.4 ... linking ... done. [3 of 8] Compiling Utils( Utils.hs, Utils.o ) [4 of 8] Compiling Semantics.Pure ( Semantics/Pure.hs, Semantics/Pure.o ) [5 of 8] Compiling Database ( Database.hs, Database.o ) [6 of 8] Compiling XPathDSL ( XPathDSL.hs, XPathDSL.o ) [7 of 8] Compiling QueryParse ( QueryParse.hs, QueryParse.o ) [8 of 8] Compiling Main ( Main.hs, Main.o ) Linking Main ... But profiling one fails: $ ghc -prof -auto -auto-all -fforce-recomp --make -cpp -O -DXQUERY2_TEST Main [1 of 8] Compiling Text.XML.Expat.FormatCustom ( Text/XML/Expat/FormatCustom.hs, Text/XML/Expat/FormatCustom.o ) [2 of 8] Compiling DataStructures ( DataStructures.hs, DataStructures.o ) Loading package ghc-prim ... linking ... done. Loading package integer ... linking ... done. Loading package base ... linking ... done. DataStructures.hs:1:0: Dynamic linking required, but this is a non-standard build (eg. prof). You need to build the program twice: once the normal way, and then in the desired way using -osuf to set the object file suffix. The error message is somewhat cryptic to me. Does anyone know how to perform profiling build when using TH? Regards Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell Weekly News: Issue 111 - March 28, 2009
This paper from 1994: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.36.5611 begins point 1.1 with exactly that sentence. It doesn't seem to be quoted there, so one can assume this is the original source of that sentence. I'm not sure dough. Regards Christopher Skrzętnicki 2009/3/28 Conal Elliott co...@conal.net: conal: Recursion is the goto of functional programming BTW, I certainly did not mean to take credit for this wonderful quote. I don't know the origin. I first heard it from Erik Meijer. - Conal ___ 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] Telnet handshaking
On Sun, Feb 15, 2009 at 10:25, Martijn van Steenbergen mart...@van.steenbergen.nl wrote: Are there any Haskell libraries out there that implement telnet? Bare sockets are a good approximation, but I'm looking for a library that understands the escape sequences specific to telnet. I think Yogurt http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Yogurt should implement this. If I'm right then you could simply extract necessary code. All best Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Overloading functions based on arguments?
On Fri, Feb 13, 2009 at 22:37, John A. De Goes j...@n-brain.net wrote: On Feb 13, 2009, at 2:11 PM, Jonathan Cast wrote: The compiler should fail when you tell it two mutually contradictory things, and only when you tell it two mutually contradictory things. By definition, it's not a contradiction when the symbol is unambiguously typeable. Do you think math textbooks are filled with contradictions when they give '+' a different meaning for vectors than matrices or real numbers??? I can easily imagine a book which uses some operator in ambiguous way yet relies on readers' intelligence in solving that issue. It is OK to do that as long as it is easy. However: it can get arbitrarily worse. I would consider any book which is hard to read because of that badly written. Things are quite similar with the code. Type is implicitly or explicitly a part of the definition of every function. It's not the name that need be unique, but the name over a given domain. When two functions have different domains, the same name can be unambiguously used to describe both of them. I think the whole point is not about what is and what isn't possible to implement. For example GHC often can do just fine with undecidable instances despite the problems they may cause. Programming language should be easy to reason about for both computers and humans. Compiler should therefore disallow programming style that is inaccessible for potential readers. Want to overload something? Well, use typeclasses to be explicit about it. All best Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: [Haskell] Google Summer of Code 2009
On Thu, Feb 12, 2009 at 11:36, Malcolm Wallace malcolm.wall...@cs.york.ac.uk wrote: Gwern Branwen gwe...@gmail.com wrote: * A GUI interface to Darcs (http://hackage.haskell.org/trac/summer-of-code/ticket/17); I wonder whether darcs ought to apply to be a GSoC mentoring organisation in its own right this year? It would be good to attempt to get a couple of dedicated slots for darcs only (in addition to any that haskell.org may get). * Optimization of containers (http://hackage.haskell.org/trac/summer-of-code/ticket/1549). Would benefit every Haskell user very quickly. This was Jamie Brandon's GSoC project last year, and although that is not yet in wide use, I suspect there is very little extra effort needed to get it out there into the average Haskell user's hands. * XMonad compositing support (http://hackage.haskell.org/trac/summer-of-code/ticket/1548). Maybe XMonad should also think about whether to apply to GSoC in their own right as a mentoring org? As a project, it seems to have a lot of life independent of the Haskell community. By the way: I think it may be worthwile to contact Google to point out the recent growth of Haskell community. I don't know on what basis they assign the slots, but it may be beneficial to do so. All best Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to deal with utf-8?
On Fri, Feb 13, 2009 at 08:06, Magicloud magicloud.magiclo...@gmail.com wrote: Hi, I am using Text.CSV to read and using gtk2hs to display csv files using utf-8 encode. Well, it displays broken strings, seems like it cannot deal with utf-8. What should I do? You should try using functions from utf8-string package (find it on Hackage) to read UTF-8 encoded data. That's about reading data in. I'm not so sure however about the gtk2hs part. Experts should tell you if it is possible or not. (I think it is.) All best Christopher Skrzętnicki P.S. I think beginn...@haskell.org is a better place to ask such questions. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Gtk2HS 0.10.0 Released
2009/2/11 Gwern Branwen gwe...@gmail.com:
touch tools/c2hs/c2hsLocal.deps; /home/gwern/bin/bin/ghc -M -dep-makefile
-optdeptools/c2hs/c2hsLocal.deps -fglasgow-exts -O
-itools/c2hs/base/admin:tools/c2hs/base/errors:tools/c2hs/base/general:tools/c2hs/base/state:tools/c2hs/base/syms:tools/c2hs/base/syntax:tools/c2hs/c:tools/c2hs/chs:tools/c2hs/gen:tools/c2hs/state:tools/c2hs/toplevel
-package-conf package.conf.inplace -hide-all-packages -package base-4.0.0.0
-package haskell98-1.0.1.0 -package pretty-1.0.1.0 -package
containers-0.2.0.0 -package array-0.2.0.0
tools/c2hs/base/admin/BaseVersion.hs tools/c2hs/base/admin/Config.hs
tools/c2hs/base/errors/Errors.hs tools/c2hs/base/general/DLists.hs
tools/c2hs/base/general/FileOps.hs tools/c2hs/base/general/FNameOps.hs
tools/c2hs/base/general/Map.hs tools/c2hs/base/general/Position.hs
tools/c2hs/base/general/Set.hs tools/c2hs/base/general/UNames.hs
tools/c2hs/base/general/Binary.hs tools/c2hs/base/general/FastMutInt.hs
tools/c2hs/base/state/CIO.hs tools/c2hs/base/state/StateBase.hs
tools/c2hs/base/state/State.hs tools/c2hs/base/state/StateTrans.hs
tools/c2hs/base/syms/Attributes.hs tools/c2hs/base/syms/Idents.hs
tools/c2hs/base/syms/NameSpaces.hs tools/c2hs/base/syntax/Lexers.hs
tools/c2hs/c/CAST.hs tools/c2hs/c/CAttrs.hs tools/c2hs/c/CBuiltin.hs
tools/c2hs/c/C.hs tools/c2hs/c/CLexer.hs tools/c2hs/c/CNames.hs
tools/c2hs/c/CParser.hs tools/c2hs/c/CParserMonad.hs tools/c2hs/c/CPretty.hs
tools/c2hs/c/CTokens.hs tools/c2hs/c/CTrav.hs tools/c2hs/chs/CHS.hs
tools/c2hs/chs/CHSLexer.hs tools/c2hs/gen/CInfo.hs tools/c2hs/gen/GBMonad.hs
tools/c2hs/gen/GenBind.hs tools/c2hs/gen/GenHeader.hs
tools/c2hs/state/C2HSState.hs tools/c2hs/state/Switches.hs
tools/c2hs/toplevel/Main.hs tools/c2hs/toplevel/Version.hs
tools/c2hs/toplevel/C2HSConfig.hs;
gcc -E -x c -traditional-cpp -I/usr/include/glib-2.0
-I/usr/lib/glib-2.0/include -DGTK2HS_HS_PREPROC -include gtk2hs-config.h
glib/System/Glib/GObject.chs.pp -o glib/System/Glib/GObject.chs
glib/System/Glib/GObject.chs.pp:38: error: missing expression between '('
and ')'
glib/System/Glib/GObject.chs.pp:91: error: missing expression between '('
and ')'
make: *** [glib/System/Glib/GObject.chs] Error 1
Ah, It feels familiar. I'm didn't get this error, but I do recall a
recent thread with similar error. However AFAIR that thread was about
building on Windows, not Ubuntu. It turned out that configure script
was somewhat broken and specific symbols needed for CPP where declared
to be empty strings. This might be happening in your case too. I
think.
All best
Christopher Skrzętnicki
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Re: [Haskell-cafe] Re: [Haskell] Google Summer of Code 2009
On Wed, Feb 11, 2009 at 21:00, Jamie hask...@datakids.org wrote: Hi Gwern, On Wed, 11 Feb 2009, Gwern Branwen wrote: I just checked H.263 and it looks like it does not require patent licensing at all (it is created by ITU-T Video Coding Experts Group (VCEG)) so one can write H.263 in Haskell and release freely without patent licensing issues. So writing H.263 in Haskell could be a good GSoC project. One mentioned that GHC produce slow code, well H.263 could be a good test case to improve GHC optimization over time. In The Computer Language Benchmarks Game, Haskell has some catching up to do. :) It does sound like a reasonably discrete task, and it sounds like you have a use for it; but I wonder if it's doable in a single summer? I have no idea, I have not dig deeper into H.263 C source code but I guess it should be quite trivial as it is a black box with video frame input and output with several parameters for encoding and just frame in/out for decoding. I didn't dig into the source code either, but I've just skimmed through Wikipedia page on that codec: http://en.wikipedia.org/wiki/H.263 and in seems far from trivial. Anything that has 23 annexes is likely to be quite complex :-) Therefore I seriously doubt chances for success of such project. I did some checks: in libavcodec at least following files consist of implementation of H.263: h263.c h263data.h h263dec.c h263.h h263_parser.c h263_parser.h How many lines are there? [te...@laptener libavcodec]$ wc h263* 6295 19280 218932 h263.c 314 2117 10423 h263data.h 816 2171 26675 h263dec.c 46217 2032 h263.h 91282 2361 h263_parser.c 29165 1047 h263_parser.h 7591 24232 261470 razem In Haskell project one would also need to provide some additional utility code which is part of libavcodec. Fast grep shows the tip of an iceberg: [te...@laptener libavcodec]$ grep include h263* | grep -v h263.c:#include dsputil.h h263.c:#include avcodec.h h263.c:#include mpegvideo.h h263.c:#include h263data.h h263.c:#include mpeg4data.h h263.c:#include mathops.h h263data.h:#include mpegvideo.h h263dec.c:#include avcodec.h h263dec.c:#include dsputil.h h263dec.c:#include mpegvideo.h h263dec.c:#include h263_parser.h h263dec.c:#include mpeg4video_parser.h h263dec.c:#include msmpeg4.h h263.h:#include config.h h263.h:#include msmpeg4.h h263_parser.c:#include parser.h h263_parser.h:#include parser.h Bottom line: I don't think it is reasonable to assume anyone without previous knowledge of H.263 is able to fit that project into one summer. But! It's Haskell community, and people here see the impossible happen from time to time ;-) All best Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] type metaphysics
Do they? Haskell is a programing language. Therefore legal Haskell types has to be represented by some string. And there are countably many strings (of which only a subset is legal type representation, but that's not important). All best Christopher Skrzętnicki On Mon, Feb 2, 2009 at 17:09, Gregg Reynolds d...@mobileink.com wrote: On Mon, Feb 2, 2009 at 10:05 AM, Andrew Butterfield andrew.butterfi...@cs.tcd.ie wrote: Martijn van Steenbergen wrote: To my naive mind this sounds suspiciously like the set of all sets, so it's too big to be a set. Here you're probably thinking about the distinction between countable and uncountable sets. See also: http://en.wikipedia.org/wiki/Countable_set No - it's even bigger than those ! He is thinking of proper classes, not sets. http://en.wikipedia.org/wiki/Class_(set_theory) Yes, that's my hypothesis: type constructors take us outside of set theory (ZF set theory, at least). I just can't prove it. Thanks, g ___ 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] GHC 6.11 missing time package?
It looks that you need MSYS or Cygwin to complete this build. Here you can find instructions regarding MSYS (and also GLUT, but you can ignore that part): http://www.haskell.org/pipermail/haskell-cafe/2007-September/031535.html All best Christopher Skrzętnicki 2009/2/1 Lyle Kopnicky li...@qseep.net I tried building it from hackage. I got an error: Setup.hs: sh: createProcess: does not exist (No such file or directory) ...which is very similar to the error I get if I try to build it using 6.10: Setup.hs: sh: runGenProcess: does not exist (No such file or directory) I don't know if there's something wrong with the package, or I don't have something set up right to build it on Windows. On Sat, Jan 31, 2009 at 10:13 PM, Antoine Latter aslat...@gmail.comwrote: 2009/1/31 Lyle Kopnicky li...@qseep.net: Hi folks, I'm getting ready to release a piece of software. Unfortunately due to a bug in GHC 6.10 on Windows it does not handle Ctrl+C properly. Since the bug has been fixed (thank you Simon Marlow), I figured I'd download a 6.11 build (I grabbed the 2009-01-29 version). Unfortunately, my project won't build with it because it's missing the time-1.1 package. This is sad because I had gone through the trouble to rewrite my use of oldtime to use time, thinking it was more future-proof. Is this an oversight in the nightly build, or is this package going out of GHC? Thanks, Lyle Hackage seems to have it: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/time Does that work? -Antoine ___ 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] ANN: HDBC v2.0 now available
On Sat, Jan 31, 2009 at 04:01, John Goerzen jgoer...@complete.org wrote: On Sat, Jan 31, 2009 at 01:51:54AM +0100, Krzysztof Skrz??tnicki wrote: The following change in .cabal file may solve the problems:--- flag base4 description: Choose base-4 if possible default: True library if flag(splitBase) if flag(base4) Build-Depends: base=4, old-time, time, bytestring, containers, old-locale else Build-Depends: base=3, old-time, time, bytestring, containers, old-locale else Build-Depends: base3 Build-Depends: mtl, convertible = 1.0.1, utf8-string --- It works for me and I *think* will also work for other setups, most notably GHC 6.8.*. Not out of the box. The base4 flag will be on by default for GHC 6.8.x too, and they'll get the base = 4 dep, which will break. They'd have to configure with the option to disable a flag (-f -base4 if memory serves), which is neither intuitive nor automatic. No, not really. I downloaded GHC 6.8.3 to test it, and it works: D:\biblioteki\HDBC-2.0.0cabal install -w c:\ghc\ghc-6.8.3\bin\ghc Resolving dependencies... Configuring HDBC-2.0.0.2... Preprocessing library HDBC-2.0.0.2... Preprocessing executables for HDBC-2.0.0.2... Building HDBC-2.0.0.2... [1 of 7] Compiling Database.HDBC.SqlValue ( Database/HDBC/SqlValue.hs, dist\build/Database/HDBC/SqlValue.o ) [2 of 7] Compiling Database.HDBC.ColTypes ( Database/HDBC/ColTypes.hs, dist\build/Database/HDBC/ColTypes.o ) [3 of 7] Compiling Database.HDBC.Statement ( Database/HDBC/Statement.hs, dist\build/Database/HDBC/Statement.o ) Database/HDBC/Statement.hs:15:0: Warning: Module `Control.Exception' is imported, but nothing from it is used, except perhaps instances visible in `Control.Exception' To suppress this warning, use: import Control.Exception() [4 of 7] Compiling Database.HDBC.Types ( Database/HDBC/Types.hs, dist\build/Database/HDBC/Types.o ) [5 of 7] Compiling Database.HDBC.Utils ( Database/HDBC/Utils.hs, dist\build/Database/HDBC/Utils.o ) [6 of 7] Compiling Database.HDBC.DriverUtils ( Database/HDBC/DriverUtils.hs, dist\build/Database/HDBC/DriverUtils.o ) [7 of 7] Compiling Database.HDBC( Database/HDBC.hs, dist\build/Database/HDBC.o ) C:\ghc\ghc-6.10.1\bin\ar.exe: creating dist\build\libHSHDBC-2.0.0.2.a Installing library in C:\Program Files\Haskell\HDBC-2.0.0.2\ghc-6.8.3 Registering HDBC-2.0.0.2... Reading package info from dist\\installed-pkg-config ... done. Saving old package config file... done. Writing new package config file... done. Checking: C:\ghc\ghc-6.8.3\binghc-pkg list HDBC C:/ghc/ghc-6.8.3\package.conf: HDBC-2.0.0.2 So both 6.8.3 and 6.10.1 work as expected. I can't remember the exact page in docs, but as far as i remember if Cabal fails to satisfy conditions with certain flag on its default settings the flag is changed and dependency calculation restarts. All best Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] can't build testpack
This error is due to usage of old base package in version 3.In .cabal file add dependency on base-4, in form base = 4. All best Christopher Skrzętnicki 2009/2/1 Ezekiel Smithburg tehgeekmeis...@gmail.com this is the error message i get: ezekiel-smithburgs-macbook-pro-15% runhaskell Setup.* build Preprocessing library testpack-1.0.0... Building testpack-1.0.0... [1 of 3] Compiling Test.QuickCheck.Instances ( src/Test/QuickCheck/Instances.hs, dist/build/Test/QuickCheck/Instances.o ) [2 of 3] Compiling Test.QuickCheck.Tools ( src/Test/QuickCheck/Tools.hs, dist/build/Test/QuickCheck/Tools.o ) [3 of 3] Compiling Test.HUnit.Tools ( src/Test/HUnit/Tools.hs, dist/build/Test/HUnit/Tools.o ) src/Test/HUnit/Tools.hs:28:36: Class `Control.Exception.Exception' used as a type In the type `Control.Exception.Exception' In the type `Control.Exception.Exception - IO a - IO ()' In the type `String - Control.Exception.Exception - IO a - IO ()' what should i do? need this in order to build hdbc 2.0, which i'm hoping solves a problem i was having earlier (memory leak). ___ 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] can't build testpack
2009/2/1 Ezekiel Smithburg tehgeekmeis...@gmail.com solution to that problem: deleted the lines from If flag(splitBase) on and changed base in Build-Depends to base = 4. Well, this is exactly what I suggested in the first place: This error is due to usage of old base package in version 3. In .cabal file add dependency on base-4, in form base = 4. Regarding second qustion: random 1.0.0.1 is installed, i've verified that. what does this error mean? It means that .cabal file fails to specify dependancy on random package. Add dependancy on random package next to base=4. This should help. All best Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] can't build testpack
testpack builds fine for me. In the original .cabal file there are following lines: If flag(splitBase) Build-Depends: base = 3, containers, random Else Build-Depends: base 3 Now that I think about it you didn't actually said what is your GHC version. Knowing that you can replace lines above with one line that matches your specific configuration. GHC 6.8.3 : Build-Depends: base = 4, containers, random GHC 6.10.1 : Build-Depends: base = 3, containers, random Please take care to restore and modify the original file. I think you should read Cabal user guide. This will save your time in the future: http://www.haskell.org/ghc/docs/latest/html/Cabal/index.html I *hope* those changes will fix your installation. I can't really test it, because testpack build fine with my version of cabal: C:\Documents and Settings\Methariuscabal install testpack --reinstall Resolving dependencies... 'testpack-1.0.0' is cached. Configuring testpack-1.0.0... Preprocessing library testpack-1.0.0... Building testpack-1.0.0... [1 of 3] Compiling Test.QuickCheck.Instances ( src\Test\QuickCheck\Instances.hs, dist\build\Test\QuickCheck\Instances.o ) [2 of 3] Compiling Test.QuickCheck.Tools ( src\Test\QuickCheck\Tools.hs, dist\build\Test\QuickCheck\Tools.o ) [3 of 3] Compiling Test.HUnit.Tools ( src\Test\HUnit\Tools.hs, dist\build\Test\HUnit\Tools.o ) C:\ghc\ghc-6.10.1\bin\ar.exe: creating dist\build\libHStestpack-1.0.0.a Installing library in C:\Program Files\Haskell\testpack-1.0.0\ghc-6.10.1 Registering testpack-1.0.0... Reading package info from dist\\installed-pkg-config ... done. Writing new package config file... done. C:\Documents and Settings\Methariuscabal install -w c:\ghc\ghc-6.8.3\bin\ghc testpack --reinstall Resolving dependencies... 'testpack-1.0.0' is cached. Configuring testpack-1.0.0... Preprocessing library testpack-1.0.0... Building testpack-1.0.0... [1 of 3] Compiling Test.QuickCheck.Instances ( src/Test/QuickCheck/Instances.hs, dist\build/Test/QuickCheck/Instances.o ) [2 of 3] Compiling Test.QuickCheck.Tools ( src/Test/QuickCheck/Tools.hs, dist\build/Test/QuickCheck/Tools.o ) [3 of 3] Compiling Test.HUnit.Tools ( src/Test/HUnit/Tools.hs, dist\build/Test/HUnit/Tools.o ) C:\ghc\ghc-6.10.1\bin\ar.exe: creating dist\build\libHStestpack-1.0.0.a Installing library in C:\Program Files\Haskell\testpack-1.0.0\ghc-6.8.3 Registering testpack-1.0.0... Reading package info from dist\\installed-pkg-config ... done. Saving old package config file... done. Writing new package config file... done. Perhaps it may also be the difference of installing with cabal install and runhaskell Setup build. All best Christopher Skrzętnicki 2009/2/1 Ezekiel Smithburg tehgeekmeis...@gmail.com oddly, when i do that, i'm back to the original error message. and sorry, i didn't understand what you meant, apparently. On Sat, Jan 31, 2009 at 7:41 PM, Krzysztof Skrzętnicki gte...@gmail.comwrote: 2009/2/1 Ezekiel Smithburg tehgeekmeis...@gmail.com solution to that problem: deleted the lines from If flag(splitBase) on and changed base in Build-Depends to base = 4. Well, this is exactly what I suggested in the first place: This error is due to usage of old base package in version 3. In .cabal file add dependency on base-4, in form base = 4. Regarding second qustion: random 1.0.0.1 is installed, i've verified that. what does this error mean? It means that .cabal file fails to specify dependancy on random package. Add dependancy on random package next to base=4. This should help. All best Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] can't build testpack
Trying to follow Ezekiel's steps I bumped into this: D:\biblioteki\testpack-1.0.0cabal configure Configuring testpack-1.0.0... D:\biblioteki\testpack-1.0.0cabal build Preprocessing library testpack-1.0.0... Building testpack-1.0.0... [1 of 3] Compiling Test.QuickCheck.Instances ( src\Test\QuickCheck\Instances.hs, dist\build\Test\QuickCheck\Instances.o ) [2 of 3] Compiling Test.QuickCheck.Tools ( src\Test\QuickCheck\Tools.hs, dist\build\Test\QuickCheck\Tools.o ) [3 of 3] Compiling Test.HUnit.Tools ( src\Test\HUnit\Tools.hs, dist\build\Test\HUnit\Tools.o ) src\Test\HUnit\Tools.hs:28:36: Class `Control.Exception.Exception' used as a type In the type `Control.Exception.Exception' In the type `Control.Exception.Exception - IO a - IO ()' In the type `String - Control.Exception.Exception - IO a - IO ()' D:\biblioteki\testpack-1.0.0cabal install Resolving dependencies... Configuring testpack-1.0.0... Preprocessing library testpack-1.0.0... Building testpack-1.0.0... [3 of 3] Compiling Test.HUnit.Tools ( src\Test\HUnit\Tools.hs, dist\build\Test\HUnit\Tools.o ) C:\ghc\ghc-6.10.1\bin\ar.exe: creating dist\build\libHStestpack-1.0.0.a Installing library in C:\Program Files\Haskell\testpack-1.0.0\ghc-6.10.1 Registering testpack-1.0.0... Reading package info from dist\\installed-pkg-config ... done. Writing new package config file... done. In short: cabal configure cabal build fails, whereas cabal install builds fine. Looks like a bug in cabal-install. Am I right? All best Christopher Skrzętnicki On Sun, Feb 1, 2009 at 03:01, Krzysztof Skrzętnicki gte...@gmail.comwrote: testpack builds fine for me. In the original .cabal file there are following lines: If flag(splitBase) Build-Depends: base = 3, containers, random Else Build-Depends: base 3 Now that I think about it you didn't actually said what is your GHC version. Knowing that you can replace lines above with one line that matches your specific configuration. GHC 6.8.3 : Build-Depends: base = 4, containers, random GHC 6.10.1 : Build-Depends: base = 3, containers, random Please take care to restore and modify the original file. I think you should read Cabal user guide. This will save your time in the future: http://www.haskell.org/ghc/docs/latest/html/Cabal/index.html I *hope* those changes will fix your installation. I can't really test it, because testpack build fine with my version of cabal: C:\Documents and Settings\Methariuscabal install testpack --reinstall Resolving dependencies... 'testpack-1.0.0' is cached. Configuring testpack-1.0.0... Preprocessing library testpack-1.0.0... Building testpack-1.0.0... [1 of 3] Compiling Test.QuickCheck.Instances ( src\Test\QuickCheck\Instances.hs, dist\build\Test\QuickCheck\Instances.o ) [2 of 3] Compiling Test.QuickCheck.Tools ( src\Test\QuickCheck\Tools.hs, dist\build\Test\QuickCheck\Tools.o ) [3 of 3] Compiling Test.HUnit.Tools ( src\Test\HUnit\Tools.hs, dist\build\Test\HUnit\Tools.o ) C:\ghc\ghc-6.10.1\bin\ar.exe: creating dist\build\libHStestpack-1.0.0.a Installing library in C:\Program Files\Haskell\testpack-1.0.0\ghc-6.10.1 Registering testpack-1.0.0... Reading package info from dist\\installed-pkg-config ... done. Writing new package config file... done. C:\Documents and Settings\Methariuscabal install -w c:\ghc\ghc-6.8.3\bin\ghc testpack --reinstall Resolving dependencies... 'testpack-1.0.0' is cached. Configuring testpack-1.0.0... Preprocessing library testpack-1.0.0... Building testpack-1.0.0... [1 of 3] Compiling Test.QuickCheck.Instances ( src/Test/QuickCheck/Instances.hs, dist\build/Test/QuickCheck/Instances.o ) [2 of 3] Compiling Test.QuickCheck.Tools ( src/Test/QuickCheck/Tools.hs, dist\build/Test/QuickCheck/Tools.o ) [3 of 3] Compiling Test.HUnit.Tools ( src/Test/HUnit/Tools.hs, dist\build/Test/HUnit/Tools.o ) C:\ghc\ghc-6.10.1\bin\ar.exe: creating dist\build\libHStestpack-1.0.0.a Installing library in C:\Program Files\Haskell\testpack-1.0.0\ghc-6.8.3 Registering testpack-1.0.0... Reading package info from dist\\installed-pkg-config ... done. Saving old package config file... done. Writing new package config file... done. Perhaps it may also be the difference of installing with cabal install and runhaskell Setup build. All best Christopher Skrzętnicki 2009/2/1 Ezekiel Smithburg tehgeekmeis...@gmail.com oddly, when i do that, i'm back to the original error message. and sorry, i didn't understand what you meant, apparently. On Sat, Jan 31, 2009 at 7:41 PM, Krzysztof Skrzętnicki gte...@gmail.comwrote: 2009/2/1 Ezekiel Smithburg tehgeekmeis...@gmail.com solution to that problem: deleted the lines from If flag(splitBase) on and changed base in Build-Depends to base = 4. Well, this is exactly what I suggested in the first place: This error is due to usage of old base package in version 3. In .cabal file add dependency on base-4, in form base = 4
Re: [Haskell-cafe] can't build testpack
You need to reinstall random package with profiling libraries enabled. This is simple: cabal install random --reinstall --enable-library-profiling I think all libraries that ships with GHC should have profiling libraries build too, but for some reason it is not so. All best Christopher Skrzętnicki On Sun, Feb 1, 2009 at 03:32, Ezekiel Smithburg tehgeekmeis...@gmail.comwrote: tried that version, it gets rid of that error message but now i have this one: ezekiel-smithburgs-macbook-pro-15% cabal --flag=split-base configure -p Configuring testpack-1.0.0... ezekiel-smithburgs-macbook-pro-15% cabal build Preprocessing library testpack-1.0.0... Building testpack-1.0.0... [1 of 3] Compiling Test.QuickCheck.Instances ( src/Test/QuickCheck/Instances.hs, dist/build/Test/QuickCheck/Instances.o ) [2 of 3] Compiling Test.QuickCheck.Tools ( src/Test/QuickCheck/Tools.hs, dist/build/Test/QuickCheck/Tools.o ) [3 of 3] Compiling Test.HUnit.Tools ( src/Test/HUnit/Tools.hs, dist/build/Test/HUnit/Tools.o ) src/Test/HUnit/Tools.hs:23:7: Could not find module `System.Random': Perhaps you haven't installed the profiling libraries for package random-1.0.0.1? Use -v to see a list of the files searched for. i'll start reading the cabal user guide and see if i can figure it out on my own, but i figure progress on this should be up on the list so if someone else has this problem, they can find this and solve it on their own. also, if someone else can figure it out before i do, that's cool too. thanks for your help so far! On Sat, Jan 31, 2009 at 8:14 PM, Krzysztof Skrzętnicki gte...@gmail.comwrote: Ok, sorry for the confusion, I should have checked it before: testpack doesn't really need base-4, it needs base-3.The right dependency line is (for both 6.10.1 and 6.8.3): Build-Depends: base = 3 4 , containers, random I really need to get some sleep... All best Christopher Skrzętnicki On Sun, Feb 1, 2009 at 03:07, Krzysztof Skrzętnicki gte...@gmail.comwrote: Trying to follow Ezekiel's steps I bumped into this: D:\biblioteki\testpack-1.0.0cabal configure Configuring testpack-1.0.0... D:\biblioteki\testpack-1.0.0cabal build Preprocessing library testpack-1.0.0... Building testpack-1.0.0... [1 of 3] Compiling Test.QuickCheck.Instances ( src\Test\QuickCheck\Instances.hs, dist\build\Test\QuickCheck\Instances.o ) [2 of 3] Compiling Test.QuickCheck.Tools ( src\Test\QuickCheck\Tools.hs, dist\build\Test\QuickCheck\Tools.o ) [3 of 3] Compiling Test.HUnit.Tools ( src\Test\HUnit\Tools.hs, dist\build\Test\HUnit\Tools.o ) src\Test\HUnit\Tools.hs:28:36: Class `Control.Exception.Exception' used as a type In the type `Control.Exception.Exception' In the type `Control.Exception.Exception - IO a - IO ()' In the type `String - Control.Exception.Exception - IO a - IO ()' D:\biblioteki\testpack-1.0.0cabal install Resolving dependencies... Configuring testpack-1.0.0... Preprocessing library testpack-1.0.0... Building testpack-1.0.0... [3 of 3] Compiling Test.HUnit.Tools ( src\Test\HUnit\Tools.hs, dist\build\Test\HUnit\Tools.o ) C:\ghc\ghc-6.10.1\bin\ar.exe: creating dist\build\libHStestpack-1.0.0.a Installing library in C:\Program Files\Haskell\testpack-1.0.0\ghc-6.10.1 Registering testpack-1.0.0... Reading package info from dist\\installed-pkg-config ... done. Writing new package config file... done. In short: cabal configure cabal build fails, whereas cabal install builds fine. Looks like a bug in cabal-install. Am I right? All best Christopher Skrzętnicki On Sun, Feb 1, 2009 at 03:01, Krzysztof Skrzętnicki gte...@gmail.comwrote: testpack builds fine for me. In the original .cabal file there are following lines: If flag(splitBase) Build-Depends: base = 3, containers, random Else Build-Depends: base 3 Now that I think about it you didn't actually said what is your GHC version. Knowing that you can replace lines above with one line that matches your specific configuration. GHC 6.8.3 : Build-Depends: base = 4, containers, random GHC 6.10.1 : Build-Depends: base = 3, containers, random Please take care to restore and modify the original file. I think you should read Cabal user guide. This will save your time in the future: http://www.haskell.org/ghc/docs/latest/html/Cabal/index.html I *hope* those changes will fix your installation. I can't really test it, because testpack build fine with my version of cabal: C:\Documents and Settings\Methariuscabal install testpack --reinstall Resolving dependencies... 'testpack-1.0.0' is cached. Configuring testpack-1.0.0... Preprocessing library testpack-1.0.0... Building testpack-1.0.0... [1 of 3] Compiling Test.QuickCheck.Instances ( src\Test\QuickCheck\Instances.hs, dist\build\Test\QuickCheck\Instances.o ) [2 of 3] Compiling Test.QuickCheck.Tools ( src\Test\QuickCheck\Tools.hs, dist\build\Test\QuickCheck\Tools.o
Re: [Haskell-cafe] ANN: HDBC v2.0 now available
On Sat, Jan 31, 2009 at 00:07, Valentyn Kamyshenko kam...@kamysh.orgwrote: Hello John, I'm trying to install the new version of HDBC on my Mac (ghc version is 6.10.1), and get the following error: # cabal upgrade --global Resolving dependencies... 'HDBC-2.0.0' is cached. Configuring HDBC-2.0.0... Preprocessing library HDBC-2.0.0... Preprocessing executables for HDBC-2.0.0... Building HDBC-2.0.0... [1 of 7] Compiling Database.HDBC.SqlValue ( Database/HDBC/SqlValue.hs, dist/build/Database/HDBC/SqlValue.o ) [2 of 7] Compiling Database.HDBC.ColTypes ( Database/HDBC/ColTypes.hs, dist/build/Database/HDBC/ColTypes.o ) [3 of 7] Compiling Database.HDBC.Statement ( Database/HDBC/Statement.hs, dist/build/Database/HDBC/Statement.o ) Database/HDBC/Statement.hs:113:9: Type constructor `Exception' used as a class In the instance declaration for `Exception SqlError' cabal: Error: some packages failed to install: HDBC-2.0.0 failed during the building phase. The exception was: exit: ExitFailure 1 I got the same error: Windows XP, GHC 6.10.1. For some reason imported Control.Exception module appears to be 6.8.* version. All best Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANN: HDBC v2.0 now available
On Sat, Jan 31, 2009 at 00:45, Krzysztof Skrzętnicki gte...@gmail.comwrote: On Sat, Jan 31, 2009 at 00:07, Valentyn Kamyshenko kam...@kamysh.orgwrote: Hello John, I'm trying to install the new version of HDBC on my Mac (ghc version is 6.10.1), and get the following error: # cabal upgrade --global Resolving dependencies... 'HDBC-2.0.0' is cached. Configuring HDBC-2.0.0... Preprocessing library HDBC-2.0.0... Preprocessing executables for HDBC-2.0.0... Building HDBC-2.0.0... [1 of 7] Compiling Database.HDBC.SqlValue ( Database/HDBC/SqlValue.hs, dist/build/Database/HDBC/SqlValue.o ) [2 of 7] Compiling Database.HDBC.ColTypes ( Database/HDBC/ColTypes.hs, dist/build/Database/HDBC/ColTypes.o ) [3 of 7] Compiling Database.HDBC.Statement ( Database/HDBC/Statement.hs, dist/build/Database/HDBC/Statement.o ) Database/HDBC/Statement.hs:113:9: Type constructor `Exception' used as a class In the instance declaration for `Exception SqlError' cabal: Error: some packages failed to install: HDBC-2.0.0 failed during the building phase. The exception was: exit: ExitFailure 1 I got the same error: Windows XP, GHC 6.10.1. For some reason imported Control.Exception module appears to be 6.8.* version. I found a (temporary) fix: change dependancy in .cabal file to state base = 4. Otherwise cabal-install selects base-3 which is the cause of the problems. All best Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANN: HDBC v2.0 now available
The following change in .cabal file may solve the problems:--- flag base4 description: Choose base-4 if possible default: True library if flag(splitBase) if flag(base4) Build-Depends: base=4, old-time, time, bytestring, containers, old-locale else Build-Depends: base=3, old-time, time, bytestring, containers, old-locale else Build-Depends: base3 Build-Depends: mtl, convertible = 1.0.1, utf8-string --- It works for me and I *think* will also work for other setups, most notably GHC 6.8.*. All best Christopher Skrzętnicki On Sat, Jan 31, 2009 at 01:31, John Goerzen jgoer...@complete.org wrote: On Sat, Jan 31, 2009 at 12:52:02AM +0100, Krzysztof Skrz??tnicki wrote: I got the same error: Windows XP, GHC 6.10.1. For some reason imported Control.Exception module appears to be 6.8.* version. I found a (temporary) fix: change dependancy in .cabal file to state base = 4. Otherwise cabal-install selects base-3 which is the cause of the problems. Thanks for the hint for folks. Why would cabal-install select a different base than running Setup manually? I can't hard-code base = 4 into .cabal because that would break for GHC 6.8 users. I have CPP code that selects what to compile based on GHC version. -- John ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] how to implement daemon start and stop directives?
When you succeed please write about it - I'd love to read about it!I was interested in writing a deamon in the past but didn't have time for it and a nice tutorial would probably help a lot. All best Christopher Skrzętnicki On Sun, Jan 25, 2009 at 02:57, Belka lambda-be...@yandex.ru wrote: If you want a normal daemon, you want to look at System.Posix.Process to create a proper daemon (forkProcess, createSession; don't forget to close stdOutput (and, errr, Haskell library types: stdin and stderr are where? not System.Posix.IO with stdOutput) and reopen them on / dev/null, at least if they're ttys as determined by System.Posix.Terminal.queryTerminal). You also want to write out a pidfile (/var/run/programname.pid) for use by startproc / killproc, and you want to install a handler for sigTERM (System.Posix.Signals.installHandler) which sets the exit flag (TVar, MVar, IORef, Chan, take your pick). Ideally you also catch sigHUP and reload your state. Thanks for the guide, Brandon !! By the way, I found a piece of code with function (daemonize :: IO () - IO ()) (http://sneakymustard.com/2008/12/11/haskell-daemons), which is close to the subject. I guess now I'm ready to implement my own daemon! Thanks for your help, everyboby!! =) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Employment
There are quite a few people with working Haskell knowledge in Wroclaw. I'm sure many of my colleagues (from University of Wroclaw: http://www.ii.uni.wroc.pl/ http://www.ii.uni.wroc.pl/cms/) know Haskell and I think would enjoy working with it. All best Christopher Skrzętnicki On Fri, Jan 23, 2009 at 23:31, Bartosz Wójcik bar...@sudety.it wrote: On Monday 19 January 2009 23:26:09 Sittampalam, Ganesh wrote: We (Credit Suisse) have Haskell developers in both London and NY, although the page only listed NY (I've now corrected it). If CS had Haskell positions in Wroclaw, Poland I'd apply for it! Best, Bartek ___ 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] Re: Does readFile /proc/mounts hang for you?
Same for me: Linux tenserwer 2.6.28-ARCH #1 SMP PREEMPT Tue Jan 6 10:26:22 UTC 2009 i686 AMD Athlon(tm) 64 Processor 3000+ AuthenticAMD GNU/Linux The Glorious Glasgow Haskell Compilation System, version 6.10.1 All best Christopher Skrzętnicki On Wed, Jan 21, 2009 at 23:27, Ertugrul Soeylemez e...@ertes.de wrote: David Fox dds...@gmail.com wrote: I posted a bug about this (http://hackage.haskell.org/trac/ghc/ticket/2971) but its so odd I had to ask here. Using ghc 6.10.1, both readFile /proc/mounts and Data.ByteString.Lazy.Char8.readFile /proc/mounts hang on an amd64 machine running Linux. Also, Data.ByteString.readFile /proc/mounts returns the empty string. Is this behavior present for others? On i386? I can confirm this on Athlon64 X2 with GHC 6.10.1 running Linux 2.6.25. Same behavior here. Greets, Ertugrul. -- nightmare = unsafePerformIO (getWrongWife = sex) http://blog.ertes.de/ ___ 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 haskell difficulties (at least for me)
My experience from using GHC under Windows XP is very similar. Many packages (especially those involving bindings to C packages) are at least painful to build. Regarding encoding package: it compiles fine for me: C:\Documents and Settings\Methariuscabal install encoding Resolving dependencies... Downloading encoding-0.4.1... Configuring encoding-0.4.1... Preprocessing library encoding-0.4.1... Building encoding-0.4.1... [ 1 of 37] Compiling Data.Encoding.Helper.Template ( Data\Encoding\Helper\Template.hs, dist\build\Data\Encoding\Helper\Template.o ) [ 2 of 37] Compiling Data.Encoding.GB18030Data ( Data\Encoding\GB18030Data.hs, dist\build\Data\Encoding\GB18030Data.o ) [ 3 of 37] Compiling Data.Encoding.Base ( Data\Encoding\Base.hs, dist\build\Data\Encoding\Base.o ) [ 4 of 37] Compiling Data.Encoding.GB18030 ( Data\Encoding\GB18030.hs, dist\build\Data\Encoding\GB18030.o ) [ 5 of 37] Compiling Data.Encoding.KOI8U ( Data\Encoding\KOI8U.hs, dist\build\Data\Encoding\KOI8U.o ) [ 6 of 37] Compiling Data.Encoding.KOI8R ( Data\Encoding\KOI8R.hs, dist\build\Data\Encoding\KOI8R.o ) [ 7 of 37] Compiling Data.Encoding.CP1258 ( Data\Encoding\CP1258.hs, dist\build\Data\Encoding\CP1258.o ) Loading package ghc-prim ... linking ... done. Loading package integer ... linking ... done. Loading package base ... linking ... done. Loading package syb ... linking ... done. Loading package array-0.2.0.0 ... linking ... done. Loading package containers-0.2.0.0 ... linking ... done. Loading package packedstring-0.1.0.1 ... linking ... done. Loading package pretty-1.0.1.0 ... linking ... done. Loading package template-haskell ... linking ... done. Loading package bytestring-0.9.1.4 ... linking ... done. Loading package regex-base-0.72.0.2 ... linking ... done. Loading package regex-posix-0.72.0.3 ... linking ... done. Loading package regex-compat-0.71.0.1 ... linking ... done. Loading package base-3.0.3.0 ... linking ... done. [ 8 of 37] Compiling Data.Encoding.CP1257 ( Data\Encoding\CP1257.hs, dist\build\Data\Encoding\CP1257.o ) [ 9 of 37] Compiling Data.Encoding.CP1256 ( Data\Encoding\CP1256.hs, dist\build\Data\Encoding\CP1256.o ) [10 of 37] Compiling Data.Encoding.CP1255 ( Data\Encoding\CP1255.hs, dist\build\Data\Encoding\CP1255.o ) [11 of 37] Compiling Data.Encoding.CP1254 ( Data\Encoding\CP1254.hs, dist\build\Data\Encoding\CP1254.o ) [12 of 37] Compiling Data.Encoding.CP1253 ( Data\Encoding\CP1253.hs, dist\build\Data\Encoding\CP1253.o ) [13 of 37] Compiling Data.Encoding.CP1252 ( Data\Encoding\CP1252.hs, dist\build\Data\Encoding\CP1252.o ) [14 of 37] Compiling Data.Encoding.CP1251 ( Data\Encoding\CP1251.hs, dist\build\Data\Encoding\CP1251.o ) [15 of 37] Compiling Data.Encoding.CP1250 ( Data\Encoding\CP1250.hs, dist\build\Data\Encoding\CP1250.o ) [16 of 37] Compiling Data.Encoding.BootString ( Data\Encoding\BootString.hs, dist\build\Data\Encoding\BootString.o ) [17 of 37] Compiling Data.Encoding.ISO885916 ( Data\Encoding\ISO885916.hs, dist\build\Data\Encoding\ISO885916.o ) [18 of 37] Compiling Data.Encoding.ISO885915 ( Data\Encoding\ISO885915.hs, dist\build\Data\Encoding\ISO885915.o ) [19 of 37] Compiling Data.Encoding.ISO885914 ( Data\Encoding\ISO885914.hs, dist\build\Data\Encoding\ISO885914.o ) [20 of 37] Compiling Data.Encoding.ISO885913 ( Data\Encoding\ISO885913.hs, dist\build\Data\Encoding\ISO885913.o ) [21 of 37] Compiling Data.Encoding.ISO885911 ( Data\Encoding\ISO885911.hs, dist\build\Data\Encoding\ISO885911.o ) [22 of 37] Compiling Data.Encoding.ISO885910 ( Data\Encoding\ISO885910.hs, dist\build\Data\Encoding\ISO885910.o ) [23 of 37] Compiling Data.Encoding.ISO88599 ( Data\Encoding\ISO88599.hs, dist\build\Data\Encoding\ISO88599.o ) [24 of 37] Compiling Data.Encoding.ISO88598 ( Data\Encoding\ISO88598.hs, dist\build\Data\Encoding\ISO88598.o ) [25 of 37] Compiling Data.Encoding.ISO88597 ( Data\Encoding\ISO88597.hs, dist\build\Data\Encoding\ISO88597.o ) [26 of 37] Compiling Data.Encoding.ISO88596 ( Data\Encoding\ISO88596.hs, dist\build\Data\Encoding\ISO88596.o ) [27 of 37] Compiling Data.Encoding.ISO88595 ( Data\Encoding\ISO88595.hs, dist\build\Data\Encoding\ISO88595.o ) [28 of 37] Compiling Data.Encoding.ISO88594 ( Data\Encoding\ISO88594.hs, dist\build\Data\Encoding\ISO88594.o ) [29 of 37] Compiling Data.Encoding.ISO88593 ( Data\Encoding\ISO88593.hs, dist\build\Data\Encoding\ISO88593.o ) [30 of 37] Compiling Data.Encoding.ISO88592 ( Data\Encoding\ISO88592.hs, dist\build\Data\Encoding\ISO88592.o ) [31 of 37] Compiling Data.Encoding.ISO88591 ( Data\Encoding\ISO88591.hs, dist\build\Data\Encoding\ISO88591.o ) [32 of 37] Compiling Data.Encoding.UTF32 ( Data\Encoding\UTF32.hs, dist\build\Data\Encoding\UTF32.o ) [33 of 37] Compiling Data.Encoding.UTF16 ( Data\Encoding\UTF16.hs, dist\build\Data\Encoding\UTF16.o ) [34 of 37] Compiling Data.Encoding.UTF8 ( Data\Encoding\UTF8.hs, dist\build\Data\Encoding\UTF8.o ) [35 of 37] Compiling Data.Encoding.ASCII ( Data\Encoding\ASCII.hs, dist\build\Data\Encoding\ASCII.o ) [36 of 37] Compiling
Re: [Haskell-cafe] Data.List.sort, not so good?
I think you are repeating my steps :-) On sorted data (like [1..n]) quicksort is O(n^2). Please read this thread: http://www.nabble.com/(flawed-)-benchmark-:-sort-td15817832.html All best Christopher Skrzętnicki 2008/12/29 Adrian Neumann aneum...@inf.fu-berlin.de: Ah that's interesting. Now my Mergesort is exactly as fast as List.sort. I thought GHC was smart enough to do that kind of inter-module optimisation. Still, Quicksort is twice as fast, so at least one argument for a Data.List.Sort package on hackage remains. Am 29.12.2008 um 16:43 schrieb Bayley, Alistair: From: haskell-cafe-boun...@haskell.org [mailto:haskell-cafe-boun...@haskell.org] On Behalf Of Adrian Neumann I don't consider myself to be a very advanced Haskell programmer, but I could come up with a Mergesort that beats List.sort, time- and spacewise. http://hpaste.org/13403 On my machine List.sort takes ~10 sec, mergeSort 7, qs 4 (compiled with -O2). List.sort eats too much ram to sort 20.000.000 ints, my algorithms don't. QuickCheck says my implementations are correct. Your single module might be benefiting from optimisation; specifically, specialisation to Ints, which would allow the dictionary lookup to be removed. Can you get the same performance if you move your mergeSort qs functions into a separate module, and only export mergeSort qs? Alistair * Confidentiality Note: The information contained in this message, and any attachments, may contain confidential and/or privileged material. It is intended solely for the person(s) or entity to which it is addressed. Any review, retransmission, dissemination, or taking of any action in reliance upon this information by persons or entities other than the intended recipient(s) is prohibited. If you received this in error, please contact the sender and delete the material from any computer. * ___ 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] implementing python-style dictionary in Haskell
2008/11/18 kenny lu [EMAIL PROTECTED]:
Dear all,
I am trying to implement the python-style dictionary in Haskell.
Python dictionary is a data structure that maps one key to one value.
For instance, a python dictionary
d = {'a':1, 'b':2 }
maps key 'a' to 1, 'b' to 2.
Python dictionary allows for update. e.g. the statement
d['a'] = 3
changes the value pointed by 'a' from 1 to 3.
Internally, python dictionary is implemented using hash table.
My first attempt is to use Data.HashTable. However it was immediately
abandoned, as I realize the memory usage is unreasonably huge.
...
I tested all three implementations by building a dictionary of size 100.
The result shows that the Map and the Trie approaches handle collision well,
but
the IntMap approach does not.
Here is a comparison of memory usage
Map : 345 MB
IntMap : 146 MB
Trie : 282 MB
Python : 94 MB
Here is a comparison of execution time (on an intel dual core 2.0G)
Map: 26 sec
IntMap: 9 sec
Trie: 12 sec
Python: 2.24 sec
The above number shows that my implementations of python style dictionary
are space/time in-efficient as compared to python.
Can some one point out what's wrong with my implementations?
First of all, you use Strings. That's a very bad thing when you care
about memory restrictions. Fire up ghci type something like this:
let aas = replicate (1024*1024*10) 'a'
-- 22 Mb memory usage
length aas
10485760
-- 270 Mb memory usage
10 Mb string caused as much as 250 Mb increase in ghci's memory consumption.
My guess? Use hashtables with ByteStrings.
I rewrote part of your code. Results are quite promising.
Haskell:
121 Mb total memory in use
INIT time0.02s ( 0.00s elapsed)
MUT time0.84s ( 1.00s elapsed)
GCtime1.97s ( 2.02s elapsed)
EXIT time0.00s ( 0.00s elapsed)
Total time2.83s ( 3.02s elapsed)
%GC time 69.6% (66.8% elapsed)
Python:
$ time python dict.py
256
real0m2.278s
user0m2.233s
sys 0m0.078s
memory: 101 Mb (as reported by Windows' Task Manager).
The code:
--- cut ---
import qualified Data.ByteString.Lazy.Char8 as BS
import Data.Int
import Data.Bits
(...)
parse_a_line_BS :: BS.ByteString - (BS.ByteString,Int)
parse_a_line_BS line = case BS.words line of
[key,val] - (key,(read . BS.unpack) val)
_ - error parse error.
main :: IO ()
main = do
dict - HT.new (==) hashByteString
indata - (map parse_a_line_BS `fmap` BS.lines `fmap` BS.readFile in.txt)
mapM_ (\ (k,v) - HT.insert dict k v) indata
HT.lookup dict (BS.pack key256) = \v - case v of
Just vv - putStrLn (show vv)
Nothing - putStrLn
(Not found)
-- derived from Data.HashTable.hashString
hashByteString :: BS.ByteString - Int32
hashByteString = BS.foldl' f golden
where f m c = fromIntegral (ord c) * magic + hashInt32 m
magic = 0xdeadbeef
hashInt32 :: Int32 - Int32
hashInt32 x = mulHi x golden + x
mulHi :: Int32 - Int32 - Int32
mulHi a b = fromIntegral (r `shiftR` 32)
where r :: Int64
r = fromIntegral a * fromIntegral b
golden :: Int32
golden = 1013904242 -- = round ((sqrt 5 - 1) * 2^32) :: Int32
--- cut ---
I had to rewrite hashString to work for ByteStrings - basically it's
just using different foldl'.
All best
Christopher Skrzętnicki
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Re: [Haskell-cafe] catting to cat gets stuck at 135K
Yep, that's your problem. forkIO the hPut. I can see the that thing biting a lot of people. Maybe there should be a warning in docs that this particular combination: feed input read output waitForProcess is just likely to produce deadlocks? All best Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Password hashing
On Tue, Oct 28, 2008 at 16:42, Bit Connor [EMAIL PROTECTED] wrote: Hello, What library can be used to securely hash passwords? From what I understand, the bcrypt algorithm is what the experts recommend. It is described in the paper: http://www.openbsd.org/papers/bcrypt-paper.ps I couldn't find a haskell library for this. There is a BSD licensed C implementation that looks very simple here: http://www.mindrot.org/projects/py-bcrypt/ A translation to haskell should be straight forward. Alternatively, a haskell bcrypt library could directly use this implementation and provide a very light FFI wrapper. Any thoughts? Direct Haskell implementation has significant advantage of being more portable: from my experience building C libraries on Windows is much more complicated and quite often fails in default setting [1]. Fixing it may require some non-trivial (and time consuming) hacking. On the other hand reusing existing implementation is likely to be faster from developers view: just write a bunch of FFI imports and you are done. It may also benefit from C's high speed. All best Christopher Skrzętnicki [1] All regex-*, OpenGL and bunch of others ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANNOUNCE: Glob 0.1, globbing library
On Fri, Oct 17, 2008 at 22:02, Matti Niemenmaa [EMAIL PROTECTED] wrote: Greetings to all, I hereby announce the release of Glob 0.1, a small library for glob-matching purposes based on a subset of zsh's syntax. Web page at: http://iki.fi/matti.niemenmaa/glob/index.html Hackage: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Glob Simple example: match (compile foo*baz) foobarbaz == True. It can also group the contents of a directory given a list of patterns to match: globDir [compile foo*baz] a directory containing foobarbaz and joe gives ([dir/foobarbaz],[dir/joe]). Comments, complaints, feature requests, bug reports are all welcome. It should work on both GHC 6.8 and 6.10, but I've only tested the latter. Hello I tried out your package, but it doesn't seem to work correctly on Windows. I checked the code and it has directory separator hard coded, which seem to be the source of problems. Please see: http://www.haskell.org/ghc/docs/latest/html/libraries/filepath/System-FilePath-Posix.html#v%3ApathSeparators All best Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANNOUNCE: Glob 0.1, globbing library
On Sat, Oct 18, 2008 at 19:28, Matti Niemenmaa [EMAIL PROTECTED] wrote: Gah, I fail at posting to mailing lists. For posterity, the message I sent to Krzysztof: Krzysztof Skrzętnicki wrote: On Fri, Oct 17, 2008 at 22:02, Matti Niemenmaa [EMAIL PROTECTED] wrote: Web page at: http://iki.fi/matti.niemenmaa/glob/index.html Hackage: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Glob I tried out your package, but it doesn't seem to work correctly on Windows. I checked the code and it has directory separator hard coded, which seem to be the source of problems. Interesting, given that I've only tested it on Windows. ;-) Can you give an example which doesn't work? Ouch... I feel like I deserve an entry on http://failblog.org/ Somehow I assumed that globDir has type [Pattern] - FilePath - IO [FilePath] where in reality it has type [Pattern] - FilePath - IO ([[FilePath]], [FilePath]) When I saw lots of files that didn't match my query I thought there is a bug... I'll certainly doublecheck any bug reports before submitting. Sorry for the noise. All best Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] I'll do USB in Haskell - tips?
On Tue, Oct 7, 2008 at 01:55, Mauricio [EMAIL PROTECTED] wrote: Hi, I'll need to use a lot of USB at work and, after looking around, it seems there's no general USB code done. 'libusb' and 'openusb' do not seem ready enough so that wrapping them would be easier than writing from scratch. (If you think I am wrong until here and have time to write me your opinion, I'll value it a lot.) Have a look at libusb version 1.0 API. It looks pretty promising: http://libusb.wiki.sourceforge.net/Libusb1.0 All best Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] cabal upgrade
On Thu, Oct 2, 2008 at 00:00, Svein Ove Aas [EMAIL PROTECTED] wrote: That aside, why not start downloading in the background, while it's doing whatever you started cabal for? Assuming the network is working, you should have an updated package list by the time it's done; granted, it won't be used for *that* invocation, but next time you invoke cabal it will. If the download fails, just ignore it. Personally I don't like the idea: If we know that there is newer package list, why not use it? It feels somewhat unintuitive to me. All best Christophe Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] not able to compile Happy GLR examples
with Happy, version 1.16. I'm using ghc version 6.6.1. I've looked at the Just looking at the GHC version number: perhaps update to 6.8.3 would help? Best regards Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Where is OpenGL loadMatrix ?
On Thu, Sep 25, 2008 at 15:39, minh thu [EMAIL PROTECTED] wrote: Hi, I can't find the loadMatrix function in http://hackage.haskell.org/packages/archive/OpenGL/latest/doc/html/Graphics-Rendering-OpenGL-GL-CoordTrans.html Should I use loadIdentity then multMatrix instead ? Thank you, Thu ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe From what I can see in the source, loadMatrix is method of class MatrixComponent [1]: instance MatrixComponent GLfloat_ where getMatrix = getFloatv loadMatrix = glLoadMatrixf loadTransposeMatrix = glLoadTransposeMatrixfARB multMatrix_ = glMultMatrixf multTransposeMatrix = glMultTransposeMatrixfARB rotate a (Vector3 x y z) = glRotatef a x y z translate (Vector3 x y z) = glTranslatef x y z scale = glScalef However, for some reason it is not exported: MatrixOrder(..), MatrixComponent(rotate,translate,scale), Matrix(..), Best regards Christopher Skrzętnicki [1]: http://hackage.haskell.org/packages/archive/OpenGL/latest/doc/html/src/Graphics-Rendering-OpenGL-GL-CoordTrans.html#MatrixComponent ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: USB and serial port
Which version do you consider new: the current 0.1.12 or the future 1.0 version? Regards, Christopher Skrzętnicki On Fri, Aug 8, 2008 at 14:54, Maurício [EMAIL PROTECTED] wrote: Interesting! The new version of the library really deserves a wrapper. Thanks, Maurício I'm currently using partial wrapper around libusb[1] in my work. It doesn't provide full interface to the library itself, so I didn't have to translate C structures. Perhaps someone can make a regular wrapper - the libusb API is pretty small and concise. Regards, Christopher Skrzętnicki [1] http://libusb.wiki.sourceforge.net/ On Wed, Aug 6, 2008 at 23:11, Maurício [EMAIL PROTECTED] wrote: Hi, What are the alternatives to read a USB port(...) ___ 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] USB and serial port
I'm currently using partial wrapper around libusb[1] in my work. It doesn't provide full interface to the library itself, so I didn't have to translate C structures. Perhaps someone can make a regular wrapper - the libusb API is pretty small and concise. Regards, Christopher Skrzętnicki [1] http://libusb.wiki.sourceforge.net/ On Wed, Aug 6, 2008 at 23:11, Maurício [EMAIL PROTECTED] wrote: Hi, What are the alternatives to read a USB port (actually, a COM serial port with an USB adapter) in Haskell, running in Linux? Thanks, Maurício ___ 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] Exceptions
I don't really think this is possible: consider asynchronous exceptions and throwTo. http://www.haskell.org/ghc/docs/latest/html/libraries/base/Control-Exception.html#v%3AthrowTo Since it can throw just *any* exception into thread. And this thread might not be aware that anyone can throw him anything. Therefore it is not possible to catch it while compiling it's code. But Maybe I'm Just wrong. Christopher Skrzętnicki 2008/7/27 Adrian Neumann [EMAIL PROTECTED]: Hello, I think it'd be nice if the compiler could warn me if there are any exceptions which I'm not catching, similar to checked exceptions in Java. Does anyone know of a possibility to do that in Haskell? Adrian ___ 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] Libevent FFI problems
2008/7/25 Levi Greenspan [EMAIL PROTECTED]: And to not require a permanent thread for each I would like to use something like select in C or Selector in Java. I haven't found something like this in Haskell, hence the libevent wrapper. As far as I know GHC's scheduler uses select() internally. At least it was using at the time of writing this paper: Developing a high-performance web server in Concurrent Haskell http://www.haskell.org/~simonmar/papers/web-server-jfp.pdf (see page 15) Perhaps you might be interested in this paper also because of its topic. Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: Re[2]: [Haskell-cafe] ansi2html - one program, several issues
On Sun, Jul 20, 2008 at 7:25 AM, Chaddaï Fouché [EMAIL PROTECTED] wrote: That's exactly what I thought. But even if I remove the only 'try' I use the memory consumption remains unchanged: It's true, but in your case your output is almost the raw input data, which means that even without a noxious try, you still have the whole file in memory. Well hopefully not with your latest code, which I would really like to see. Here is the part that actually changed: --- split c str = let (p,ps) = aux str in (p:ps) where aux [] = ([],[]) aux (x:cs) = let (xs,xss) = aux cs in if x == c then ([c],(xs:xss)) else ((x:xs),xss) splitPred :: (Eq a) = (a - Bool) - [a] - [[a]] splitPred pr str = let (p,ps) = aux str in (p:ps) where aux [] = ([],[]) aux (x:cs) = let (xs,xss) = aux cs in if pr x then ([],((x:xs):xss)) else ((x:xs),xss) doOneFile :: String - IO () doOneFile fname = do t1 - getCurrentTime doesFileExist (fname ++ .html) = \b - if b then hPutStrLn stderr $ printf File already processed, skipping: %s fname else do src - readFile fname out - openFile (fname ++ .html) WriteMode hSetBuffering out (BlockBuffering (Just 64000)) hPutStrLn out html hPutStrLn out body bgcolor=\black\ hPutStrLn out meta http-equiv=\Content-Type\ content=\text/html; charset=UTF-8\ hPutStrLn out span style=\font-family: monospace; font-size: 13;\ span let extractData = \p - case p of Right x - x Left err - (trace . show $ err) [] let srcSplit = splitPred (`elem`\n) src let parsed = concatMap (extractData . parse mainParser fname) srcSplit execStateT (hPrintHtml (St id)) (out,emptyStyle) -- wypisujemy pierwszy wiersz execStateT (mapM_ hPrintHtml parsed) (out,emptyStyle) hPutStrLn out /span/span hPutStrLn out /body hPutStrLn out /html t2 - getCurrentTime hPutStrLn stderr $ printf File %s processed. It took %s. File size was %d characters. fname (show $ diffUTCTime t2 t1) (length src) hClose out -- The whole file is also attached. You will find there another (worse) implementation of split and a little bit of code similar to thread pool stuff. On Sun, Jul 20, 2008 at 8:17 AM, John Meacham [EMAIL PROTECTED] wrote: On Sun, Jul 20, 2008 at 02:34:09AM +0400, Bulat Ziganshin wrote: i think that Parsec library should hold entire file in memory only when you use 'try' for whole file. otherwise it should omit data as proceeded I do not believe that is the case, since the return type of runParser Either ParseError a means that before you can extract the result of the parse from the 'Right' branch, it must evaluate whether the result is 'Left' or 'Right' meaning it needs to parse the whole input in order to determine whether the parse was succesful. It's true it has to parse the whole file, but it is not true it has to reside in the memory: only the results must be there. In this case, when the result is 1-1 transformation of input, it is true. But consider this program: module Main where import Text.ParserCombinators.Parsec par = eof | (char 'a' par) alst = take 2 (repeat 'a') main = print (runParser par () alst) It runs in constant memory: $ ./partest.exe +RTS -sstderr C:\cygwin\home\Metharius\killer\killerPy\ansi2html\partest.exe +RTS -sstderr Right () 84,326,845,636 bytes allocated in the heap 22,428,536 bytes copied during GC 9,684 bytes maximum residency (1 sample(s)) 13,848 bytes maximum slop 1 MB total memory in use (0 MB lost due to fragmentation) Generation 0: 160845 collections, 0 parallel, 0.63s, 0.63s elapsed Generation 1: 1 collections, 0 parallel, 0.00s, 0.00s elapsed INIT time0.02s ( 0.00s elapsed) MUT time 54.31s ( 54.55s elapsed) GCtime0.63s ( 0.63s elapsed) EXIT time0.00s ( 0.00s elapsed) Total time 54.95s ( 55.17s elapsed) %GC time 1.1% (1.1% elapsed) Alloc rate1,552,176,623 bytes per MUT second Productivity 98.8% of total user, 98.4% of total elapsed Best regards Christopher Skrzętnicki ansi2html.hs Description: Binary data ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: Re[2]: [Haskell-cafe] ansi2html - one program, several issues
I played with another approach without any parser library, just with plain
pattern matching. The idea was to create function to match all different
cases of codes. Since I already got most of the code, it was quite easy to
do. The core function consist of cases like those:
parse ('\ESC':'[':'1':';':'4':'0':'m':rest) = modifyAndPrint (\x - x
{ bgcol = light black }) parse rest
parse ('\ESC':'[':'1':';':'4':'1':'m':rest) = modifyAndPrint (\x - x
{ bgcol = light red }) parse rest
parse ('\ESC':'[':'1':';':'4':'2':'m':rest) = modifyAndPrint (\x - x
{ bgcol = light green }) parse rest
parse ('\ESC':'[':'1':';':'4':'3':'m':rest) = modifyAndPrint (\x - x
{ bgcol = light yellow }) parse rest
If you have read the old code you should recognize some parts of it here.
It should consume rather constant amount of memory. To my surprise it
consumed almost exactly the same amount of memory as the previous program.
Turns out the problematic line was this:
hPutStrLn stderr $ printf File %s processed. It took %s. File size was
%d characters. fname (show $ diffUTCTime t2 t1) *(length src)*
It computed length of the input file. Needless to say, because src was
actually the input file parsed previously, it was all hanging in the memory.
Having removed that reference to src both programs (the one that parses
input per line and the most recent one) are running in constant memory
(2Mb). This doesn't apply to the first program, which has to read whole file
before producing any output.
And the last note: the new program is also 2x faster, perhaps due to very
simple structure that is easy to optimize. It also makes sense now to use
mapMPar as it reduces run time by 30%. The full code is in attachments.
Best regards
Christopher Skrzętnicki
ansi2html.hs
Description: Binary data
ansi2html.hs
Description: Binary data
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Re: [Haskell-cafe] ansi2html - one program, several issues
I forgot to mention that the memory consumption is several times higher than file size. On 8,3 Mb file: 532 MB total memory in use (4 MB lost due to fragmentation). Having that 8 Mb in memory is not the problem. 532 Mb is another story. In general, the program consumes roughly 64 times more memory than file size and it scales linearly. Best regards Christopher Skrzętnicki On Sat, Jul 19, 2008 at 9:52 PM, Chaddaï Fouché [EMAIL PROTECTED] wrote: 2008/7/19 Krzysztof Skrzętnicki [EMAIL PROTECTED]: Hi all 1) Profiling shows that very simple functions are source of great memory and time consumption. However, if I turn them off and simply print their input arguments instead, the overall time and memory consumption doesn't change. But now another function is acting badly. My guess: somehow the cost of Parsec code is shifted into whatever function is using it's output. Let's see: Are you using Parsec to parse the whole file ? Then your problem is there : Parsec needs to read and process the whole file before it can give us any output since it thinks it could have to give us an error instead and it can't be sure of that before he has read the whole thing... In your case, your problem is such that you would prefer to treat the file as a stream, isn't it ? There are some parser library that can give output lazily (look at polyparse flavour), another option would be to only use Parsec where you need it and just read and print the ordinary text for example. -- Jedaï ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ansi2html - one program, several issues
On Sat, Jul 19, 2008 at 11:35 PM, Chaddaï Fouché [EMAIL PROTECTED] wrote: 2008/7/19 Krzysztof Skrzętnicki [EMAIL PROTECTED]: I forgot to mention that the memory consumption is several times higher than file size. On 8,3 Mb file: 532 MB total memory in use (4 MB lost due to fragmentation). Having that 8 Mb in memory is not the problem. 532 Mb is another story. In general, the program consumes roughly 64 times more memory than file size and it scales linearly. You should be using ByteString, though this problem would be alleviated if you were consuming the file as a stream. Since ANSI color codes doesn't contain characters like newline or space, I have simply split input file into such lines. Now the whole program behaves much better: GC time is below 10% and memory consumption dropped to 74 Mb per thread. It's still a lot of memory though and it certainly holds much more than one line of text. Best regards Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: Re[2]: [Haskell-cafe] ansi2html - one program, several issues
On Sun, Jul 20, 2008 at 12:34 AM, Bulat Ziganshin [EMAIL PROTECTED] wrote: Hello Krzysztof, Sunday, July 20, 2008, 1:55:45 AM, you wrote: 532 MB total memory in use (4 MB lost due to fragmentation). i think that Parsec library should hold entire file in memory only when you use 'try' for whole file. otherwise it should omit data as proceeded That's exactly what I thought. But even if I remove the only 'try' I use the memory consumption remains unchanged: C:\cygwin\home\Metharius\killer\KillerPy\ansi2html\ansi2html_old.exe duzy.log +RTS -sstderr File duzy.log processed. It took 5.046875s. File size was 4166578 characters. 3,950,649,704 bytes allocated in the heap 535,544,056 bytes copied during GC 117,603,408 bytes maximum residency (9 sample(s)) 1,647,828 bytes maximum slop 265 MB total memory in use (2 MB lost due to fragmentation) Generation 0: 7527 collections, 0 parallel, 0.86s, 0.86s elapsed Generation 1: 9 collections, 0 parallel, 0.80s, 0.81s elapsed INIT time0.02s ( 0.00s elapsed) MUT time3.20s ( 3.63s elapsed) GCtime1.66s ( 1.67s elapsed) EXIT time0.00s ( 0.00s elapsed) Total time4.88s ( 5.30s elapsed) %GC time 34.0% (31.6% elapsed) Alloc rate1,227,386,315 bytes per MUT second Productivity 65.7% of total user, 60.5% of total elapsed One more thing to note: with partial parsing there is no longer a difference between mapM_ and mapMPar. Best regards Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] What's the difference?
On Tue, Apr 8, 2008 at 11:05 PM, PR Stanley [EMAIL PROTECTED] wrote: What is the difference between data T0 f a = MkT0 a instance Eq (T0 f a) where ... and data T0 f a = MkT0 a instance Eq a = Eq (T0 f a) where ... The second one says that TO f a is only an instance of Eq if a is, while the first says that TO f a is an instance regardless of the type of its arguments. More explanation please. :-) Well, it's similar with functions. If we try: foo :: a - a - Bool foo x y = x y We'll get an error: the usage of `` requires `a` to be in Ord class, which we write down as type signature: foo :: (Ord a) = a - a - Bool The similar effect is for type classes. Here: instance Eq a = Eq (T0 f a) where ... We can see that we can compare elements of type `a` for equality. It's kind of saying: if you give me an element of type `a`, and that type is in Eq class, I can tell you how to tell equality of elements of type T0 f a. Regards Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Shouldn't this loop indefinitely = take (last [0..]) [0..]
On Fri, Apr 4, 2008 at 7:14 PM, Jake Mcarthur [EMAIL PROTECTED] wrote: On Apr 4, 2008, at 11:31 AM, Loup Vaillant wrote: I mean, could we calculate this equality without reducing length ys to weak head normal form (and then to plain normal form)? Yes. Suppose equality over Nat is defined something like: Z == Z = True S x == S y = x == y x == y = False And also suppose the length function actually returns a Nat instead of an Int. Now the expression reduces as: length xs == length ys S (length xs') == S (length ys') Z == S (length ys'') False That would not be possible without lazy Nats. One thing to notice is that with lazy Nats this code: length [] == length [1..] would terminate, while on 64 bit platform it is almost bottom :-) Theoretically it is even worse: genericLength [] == genericLength [1..] :: Integer will never terminate and eat infinite amount of memory along the way, while genericLength [] == genericLength [1..] :: Nat will do just fine. We can however write function like this: eqLengths [] [] = True eqLengths (x:xs) (y:ys) = eqLengths ys xs eqLengths _ _ = False which looks just fine for me. Christopher Skrzętnicki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Type constraints for class instances
I fixed the code, see below. In fact, it works now for any listst of
type (YOrd a) = [a]. It works for things like
ysort [[1..],[1..],[2..],[1..]]
Unfortunately, the performance of ysort is rather low. I belive that
it is impossible to create any sorting algorithm that uses ycmp
instead of compare, that is faster than O(n^2). In fact, ysort is
Theta(n^2), and it appears to be optimal. Why?
Well, consider the bubble sort algorithm. Then ycmp will be simply
sort of swap used there:
ycmp x y = case x `compare` y of
LT - (x,y)
EQ - (x,y)
GT - (y,x)
And because it is the only possible operation here, it can't be
faster. (Though I may be wrong.)
Best regards,
Christopher Skrzętnicki.
---
--- http://hpaste.org/6536#a1
{-# OPTIONS_GHC -O2 #-}
module Data.YOrd (ysort, YOrd(..)) where
-- Well defined where Eq means equality, not only equivalence
class YOrd a where
ycmp :: a - a - (a,a)
instance (Ord a) = YOrd [a] where
ycmp = ycmpWith compare
where
ycmpWith _ xs [] = ([],xs)
ycmpWith _ [] xs = ([],xs)
ycmpWith cmp (xs'@(x:xs)) (ys'@(y:ys)) = case x `cmp` y of
LT - (xs',ys')
GT - (ys',xs')
EQ - let (sm,gt)
= xs `ycmp` ys in
(x:sm,x:gt)
-- assumes that cmp is equality not equivalence relation here!
ycmpWrap cmp x y = case x `cmp` y of
LT - (x,y)
EQ - (x,y)
GT - (y,x)
instance YOrd Integer where
ycmp = ycmpWrap compare
instance YOrd Char where
ycmp = ycmpWrap compare
instance YOrd Int where
ycmp = ycmpWrap compare
-- ysort : sorting in O(n^2)
ysort :: (YOrd a) = [a] - [a]
ysort = head . mergeAll . wrap
wrap xs = map (:[]) xs
mergeAll [] = []
mergeAll [x] = [x]
mergeAll (a:b:rest) = mergeAll ((merge a b) : (mergeAll rest))
merge xs [] = xs
merge [] xs = xs
merge (x:xs) (y:ys) = let (sm,gt) = x `ycmp` y in
sm : (merge [gt] $ merge xs ys)
2008/3/21 Stephen Marsh [EMAIL PROTECTED]:
Actually, infinite trees wouldn't work, for a similar reason to above. You
can't decide sort order on the infinite left branches, so you could never
choose the correct right branch.
Stephen
2008/3/21 Stephen Marsh [EMAIL PROTECTED]:
There is a bug in the code:
*Main ycmp [5,2] [2,5] :: ([Int], [Int])
([2,2],[5,5])
I think it is impossible to define a working (YOrd a) = YOrd [a]
instance. Consider:
let (a, b) = ycmp [[1..], [2..]] [[1..],[1..]]
head (b !! 1) -- would be nice if it was 2, but it is in fact _|_
We take forever to decide if [1..] is greater or less than [1..], so can
never decide if [1..] or [2..] comes next.
However Ord a = YOrd [a] can be made to work, and that is absolutely
awesome, esp. once you start thinking about things like Ord a = YOrd
(InfiniteTree a). This really is very cool, Krzysztof.
Stephen
2008/3/20 Krzysztof Skrzętnicki [EMAIL PROTECTED]:
Hello everyone,
I'm working on a small module for comparing things incomparable with
Ord.
More precisely I want to be able to compare equal infinite lists like
[1..].
Obviously
(1) compare [1..] [1..] = _|_
It is perfectly reasonable for Ord to behave this way.
Hovever, it doesn't have to be just this way. Consider this class
class YOrd a where
ycmp :: a - a - (a,a)
In a way, it tells a limited version of ordering, since there is no
way to get `==` out of this.
Still it can be useful when Ord fails. Consider this code:
(2) sort [ [1..], [2..], [3..] ]
It is ok, because compare can decide between any elements in finite
time.
However, this one
(3) sort [ [1..], [1..] ]
will fail because of (1). Compare is simply unable to tell that two
infinite list are equivalent.
I solved this by producing partial results while comparing lists. If
we compare lists
(1:xs)
(1:ys)
we may not be able to tell xs ys, but we do can tell that 1 will be
the first element of both of smaller and greater one.
You can see this idea in the code below.
--- cut here ---
{-# OPTIONS_GHC -O2 #-}
module Data.YOrd where
-- Well defined where Eq means equality, not only equivalence
class YOrd a where
ycmp :: a - a - (a,a)
instance (YOrd a) = YOrd [a] where
ycmp [] [] = ([],[])
ycmp xs [] = ([],xs)
ycmp [] xs = ([],xs)
ycmp xs'@(x:xs) ys'@(y:ys) = let (sm,gt) = x `ycmp` y in
let (smS,gtS) = xs `ycmp` ys in
(sm:smS, gt:gtS)
ycmpWrap x y = case x `compare` y of
LT - (x,y)
GT - (y,x)
EQ - (x,y) -- biased - but we have to make
Re: [Haskell-cafe] Type constraints for class instances
It compiles, but it doesn't work when i try to use it on lists. There
are some bugs in that code, but I need some time to fix it.
2008/3/21 Bas van Dijk [EMAIL PROTECTED]:
2008/3/21 Krzysztof Skrzętnicki [EMAIL PROTECTED]:
...
I'd like to write the following code:
instance (Ord a) = YOrd a where
ycmp x y = case x `compare` y of
LT - (x,y)
GT - (y,x)
EQ - (x,y)
But i get an error Undecidable instances for any type [a].
Does anyone know the way to solve this?
The module compiles fine when you add the following pragma's to your module:
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE UndecidableInstances #-}
See:
http://www.haskell.org/ghc/docs/latest/html/users_guide/type-class-extensions.html#instance-rules
http://www.haskell.org/ghc/docs/latest/html/users_guide/type-class-extensions.html#undecidable-instances
regards,
Bas
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[Haskell-cafe] Type constraints for class instances
Hello everyone,
I'm working on a small module for comparing things incomparable with Ord.
More precisely I want to be able to compare equal infinite lists like [1..].
Obviously
(1) compare [1..] [1..] = _|_
It is perfectly reasonable for Ord to behave this way.
Hovever, it doesn't have to be just this way. Consider this class
class YOrd a where
ycmp :: a - a - (a,a)
In a way, it tells a limited version of ordering, since there is no
way to get `==` out of this.
Still it can be useful when Ord fails. Consider this code:
(2) sort [ [1..], [2..], [3..] ]
It is ok, because compare can decide between any elements in finite time.
However, this one
(3) sort [ [1..], [1..] ]
will fail because of (1). Compare is simply unable to tell that two
infinite list are equivalent.
I solved this by producing partial results while comparing lists. If
we compare lists
(1:xs)
(1:ys)
we may not be able to tell xs ys, but we do can tell that 1 will be
the first element of both of smaller and greater one.
You can see this idea in the code below.
--- cut here ---
{-# OPTIONS_GHC -O2 #-}
module Data.YOrd where
-- Well defined where Eq means equality, not only equivalence
class YOrd a where
ycmp :: a - a - (a,a)
instance (YOrd a) = YOrd [a] where
ycmp [] [] = ([],[])
ycmp xs [] = ([],xs)
ycmp [] xs = ([],xs)
ycmp xs'@(x:xs) ys'@(y:ys) = let (sm,gt) = x `ycmp` y in
let (smS,gtS) = xs `ycmp` ys in
(sm:smS, gt:gtS)
ycmpWrap x y = case x `compare` y of
LT - (x,y)
GT - (y,x)
EQ - (x,y) -- biased - but we have to make our minds!
-- ugly, see the problem below
instance YOrd Int where
ycmp = ycmpWrap
instance YOrd Char where
ycmp = ycmpWrap
instance YOrd Integer where
ycmp = ycmpWrap
-- ysort : sort of mergesort
ysort :: (YOrd a) = [a] - [a]
ysort = head . mergeAll . wrap
wrap :: [a] - [[a]]
wrap xs = map (:[]) xs
mergeAll :: (YOrd a) = [[a]] - [[a]]
mergeAll [] = []
mergeAll [x] = [x]
mergeAll (a:b:rest) = mergeAll ((merge a b) : (mergeAll rest))
merge :: (YOrd a) = [a] - [a] - [a]
merge [] [] = []
merge xs [] = xs
merge [] xs = xs
merge (x:xs) (y:ys) = let (sm,gt) = x `ycmp` y in
sm : (merge [gt] $ merge xs ys)
--- cut here ---
I'd like to write the following code:
instance (Ord a) = YOrd a where
ycmp x y = case x `compare` y of
LT - (x,y)
GT - (y,x)
EQ - (x,y)
But i get an error Undecidable instances for any type [a].
Does anyone know the way to solve this?
Best regards
Christopher Skrzętnicki
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[Haskell-cafe] YOrd and ysort
The ysort function I've written for YOrd class was incredibly inefficient. Here is better one: ysort :: (YOrd a) = [a] - [a] ysort = head . mergeAll . wrap wrap :: [a] - [[a]] wrap xs = map (:[]) xs mergeAll :: (YOrd a) = [[a]] - [[a]] mergeAll [] = [] mergeAll [x] = [x] mergeAll (a:b:rest) = mergeAll ((merge a b) : (mergeAll rest)) merge :: (YOrd a) = [a] - [a] - [a] merge [] [] = [] merge xs [] = xs merge [] xs = xs merge xs ys = let ((sm:smS),gts) = xs `ycmp` ys in smS `seq` gts `seq` sm : (merge smS gts) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: (flawed?) benchmark : sort
In OCaml you have sort and fastsort - the latter doesn't have to be stable. It currently is, because fastsort = sort. I think it is a good thing to leave people an option, if there is something important to choose. On Thu, Mar 13, 2008 at 12:48 AM, [EMAIL PROTECTED] wrote: G'day all. Adrian Hey wrote: This might be a reasonable thing to say about *sortBy*, but not sort as the ordering of equal elements should not be observable (for any correct instance of Ord). It should be impossible to implement a function which can discriminate between [a,a],[a,b],[b,a],[b,b] if compare a b = EQ. Nonsense. Consider a Schwartzian transform wrapper: data OrdWrap k v = OrdWrap k v instance (Ord k) = Ord (OrdWrap k v) where compare (OrdWrap k1 v1) (OrdWrap k2 v2) = OrdWrap k1 k2 It would be incorrect (and not sane) for sort [a,b] to return [a,a] in this case, though a case could be made that either [a,b] or [b,a] make sense. Quoting Jules Bean [EMAIL PROTECTED]: Stability is a nice property. I don't understand why you are arguing against this so aggressiviely. Stability is an occasionally very useful property. However, if there is a tradeoff between stability and performance, I'd prefer it if the library didn't choose for me. Cheers, Andrew Bromage ___ 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] Re: (flawed?) benchmark : sort
Are you really sure that your results are correct? I obviously did all my tests with -O2 on. Please rerun your tests on the new framework. Also note that this one contains tests for three cases: - sorted - revsorted - randomized From previous results I can guess that with randomized input Yhc's code will be ~3 times slower then the fastest quicksort out there. But I'm not going to run O(n^2) algorithm to compare with O(n log n) - and this is the case for (rev?)sorted inputs. Christopher Skrzętnicki On Tue, Mar 11, 2008 at 5:14 AM, Richard A. O'Keefe [EMAIL PROTECTED] wrote: On 11 Mar 2008, at 12:27 pm, Krzysztof Skrzętnicki wrote: I've written little framework to work on. See sortbench.hs and sortbench.py attachments. Furthermore, I checked Yhc's implementation of sort: it is indeed very fast: I took his earlier code and plugged yhc's sort into it. Compiling with ghc -O2 using GHC 6.8.2, I found the yhc code (basically variant of natural merge) to be considerably slower than some of the alternatives. (...) When I run Krzystztof's test harness (which I have currently brought up to 25 different sorting functions) with a list of the form [1..N] instead of a random list, suddenly all the variants of merge sort come out ahead of all the variants of quick sort. In fact his best version of quicksort, qsort_iv, comes out fully 1155 times slower than the YHC algorithm on a list of 10,000 ordered integers. That can be improved by spending a bit of effort on choosing a good pivot, but then the quicksort algorithms are no longer so competitive for randomised inputs. This paper looks interesting, I'm going to implement those tests. The classic Engineering a Quicksort paper by Bentley and McIlroy from Software : Practice Experience recommends a whole bunch of distribution shapes (one run, two runs, sawtooth, organ pipes, random, ...) that should be benchmarked before drawing too many conclusions. This is the right point. A further work will be to add different input generators to run them too. It is also wise to try more than one data type. How do the different algorithms compare on random samples from a Scrabble dictionary? (Why that particular question? Because I mean to try it.) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
