February 2009 - Haskell-Cafe

How to properly design a Haskell TK
by Achim Schneider 06 Feb '09

06 Feb '09

I've been thinking a bit, and come to the conclusion that we should just do it as others did it before: Start off with application-specific tk's, figure out what's cool and what's compatible and then put them into libraries. In short: Stop building cathedrals. -- (c) this sig last receiving data processing entity. Inspect headers for copyright history. All rights reserved. Copying, hiring, renting, performance and/or quoting of this signature prohibited.

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Re : OpenAL
by Paul Langevin 06 Feb '09

06 Feb '09

For those who follow, I finally find the way to mix (simpler than I thought) import Sound.ALUT playSound :: IO () playSound = withProgNameAndArgs runALUT $ \ _ _ -> do ↠ buffer1 <- createBuffer $ Sine 440 0 1 ↠ buffer2 <- createBuffer $ HelloWorld ↠ [source1,source2] <- genObjectNames 2 ↠ buffer source1 $= Just buffer1 ↠ buffer source2 $= Just buffer2 ↠ play [source1,source2] ↠ sleep 2 ↠ return () main = playSound (sorry if unicode if ugly, I don't know what to do with spaces) _________________________________________________________________ Téléphonez gratuitement à tous vos proches avec Windows Live Messenger ! Téléchargez-le maintenant ! http://www.windowslive.fr/messenger/1.asp

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Re : OpenAL
by Paul Langevin 06 Feb '09

06 Feb '09

by the way, a mean to get it done without error is to not use runALUTUsingCurrentContext : import Sound.ALUT playSound :: IO () playSound = withProgNameAndArgs runALUT $ \ _ _ -> do buffer1 <- createBuffer $ Sine 440 0 1 buffer2 <- createBuffer HelloWorld [source] <- genOjectNames 1 queueBuffers source [buffer1,buffer2] play [source] sleep 2 return () main = playSound I'm not sure if haskell-cafe will take spaces into account. If not, only 7 lines should be tabulated after do. Does anyone know how to mix buffers ? _________________________________________________________________ Vous voulez savoir ce que vous pouvez faire avec le nouveau Windows Live ? Lancez-vous ! http://www.microsoft.com/windows/windowslive/default.aspx

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Automation and COM
by Günther Schmidt 06 Feb '09

06 Feb '09

Hi, has anyone yet been using Sigbjorns COM package? Sigbjorn hasn't had the time yet to gather some docs on how to use it, so I wonder if someone else could post some examples on how to use it. I'm asking because I need to do some COM stuff with excel, which I know how to do in another language, but can't seem to get it even started with haskell. Any help appreciated. Günther

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Purely funcional LU decomposition
by Rafael Gustavo da Cunha Pereira Pinto 05 Feb '09

05 Feb '09

Hello folks After a discussion on whether is possible to compile hmatrix in Windows, I decided to go crazy and do a LU decomposition entirely in Haskell... At first I thought it would be necessary to use a mutable or monadic version of Array, but then I figured out it is a purely interactive process. I am releasing this code fragment as LGPL. {- This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. -} import Data.Array.IArray type Dim=(Int,Int) lu::Array Dim Double -> (Array Dim Double,Array Dim Double) lu a = (aa l,aa u) where (l,u)=lu' a [] [] aa = accumArray (+) 0 (bounds a) lu'::(Floating e) => Array Dim e -> [(Dim,e)] -> [(Dim,e)] -> ([(Dim,e)],[(Dim,e)]) lu' a l u=if (ui==li) then ( ((ui,uj),1.0):l,((ui,uj),a!(ui,uj)):u) else (lu' an (l++ln) (u++un)) where k=li ((li,lj),(ui,uj))=bounds a lik i=(a!(i,k)/a!(k,k)) un=[((k,j),a!(k,j)) | j<-[lj..uj]] ln=((lj,lj),1.0):[((i,k),lik i) | i<-[li+1..ui]] an=array ((li+1,lj+1),(ui,uj)) [((i,j),e_an i j) | i<-[li+1..ui],j<-[lj+1..uj]] e_an i j=a!(i,j)-(lik i)*a!(k,j) Still needed: 1) Partial pivoting 2) Profiling... Lots! 3) Parallelize -- Rafael Gustavo da Cunha Pereira Pinto Electronic Engineer, MSc.

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Signatures in defining functions
by TKM 05 Feb '09

05 Feb '09

Hello, I'm kind of new with Haskell and I would like to know about the following: [some function]:: Int -> Int -> Int Now is my question, how should I interpret "Int -> Int -> Int"? Meaning what does "Int -> Int -> Int" mean? Thank you for answering my question. Kind Regards, JTKM

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Re: OpenAL
by Paul Langevin 05 Feb '09

05 Feb '09

>Does the example code at >http://articles.bluishcoder.co.nz/Haskell/OpenAL work for anyone? sorry for the delay, Brian : I can hear the two sounds one after the other (I wish I knew how to hear them at the same time). However, I've got a strange error message from ALSA : " alsa_blitbuffer: Could not write audio data to sound device: File descriptor in bad state mixer: pcm.c:2644: snd_pcm_areas_copy: Assertion 'dst_areas' failed. " (mixer is the name of the executable (because I thought...)) OpenAL version : 1.3 ALC version : 1.0 AL version : 1.1 Ghc version : 6.6 _________________________________________________________________ Téléphonez gratuitement à tous vos proches avec Windows Live Messenger ! Téléchargez-le maintenant ! http://www.windowslive.fr/messenger/1.asp

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Success (was: cURL under Windows again)
by Iliya Kuznetsov 05 Feb '09

05 Feb '09

The problem has solved. Solution, given by http://awson.livejournal.com/, is: 1. Copy libcurl-4.dll to libcurl.dll beause of namescheme 2. Before building haskell curl-1.3.4 _under windows_ you have to change #define CURL_EXTERN __declspec(dllimport) to #define CURL_EXTERN. After that, curl-7.19.3 and curl-1.3.4 work fine. ---------- Forwarded message ---------- From: Iliya Kuznetsov <iliya.kuznetsov(a)gmail.com> Date: 2009/2/2 Subject: cURL under Windows again To: haskell-cafe(a)haskell.org Hello cafe-subscribers, I saw some issues about installing haskell bindings for cURL under Windows, and now I'm trapped too. So, here is actions' log for everything (very detail; you can PgDn to the end with questions): 1. Windows Vista without UAC 2. ghc-6.10.1-i386-windows.exe is installed to C:\Program Files\Haskell "C:\Program Files\Haskell\package.conf" wasn't touched after installation (Cabal nor manually) 3. MinGW-5.1.4 installed to C:\temp\MinGW 4. MSys-1.0 installed to C:\temp\msys\1.0\ 5. curl-7.19.3.tar.bz2 had taken from http://curl.haxx.se/download/curl-7.19.3.tar.bz2 6. Under msys, curl-7.19.3.tar.bz2 is untared into /home/Kuznetsov/curl-7.19.3 7. cURL is made as: cd curl-7.19.3 $ ./configure configure: Configured to build curl/libcurl: ... curl version: 7.19.3 Host setup: i686-pc-mingw32 Install prefix: /usr/local Compiler: gcc SSL support: no (--with-ssl / --with-gnutls) SSH support: no (--with-libssh2) zlib support: no (--with-zlib) krb4 support: no (--with-krb4*) GSSAPI support: no (--with-gssapi) SPNEGO support: no (--with-spnego) c-ares support: no (--enable-ares) ipv6 support: no (--enable-ipv6) IDN support: no (--with-libidn) Build libcurl: Shared=yes, Static=yes Built-in manual: no (--enable-manual) Verbose errors: enabled (--disable-verbose) SSPI support: no (--enable-sspi) ca cert bundle: no ca cert path: no LDAP support: enabled (winldap) LDAPS support: no (--enable-ldaps) $ make ... make[2]: Leaving directory `/home/Kuznetsov/curl-7.19.3/src' make[1]: Leaving directory `/home/Kuznetsov/curl-7.19.3/src' make[1]: Entering directory `/home/Kuznetsov/curl-7.19.3' make[1]: Nothing to be done for `all-am'. make[1]: Leaving directory `/home/Kuznetsov/curl-7.19.3' $ make install ... libtool: install: /bin/install -c .libs/libcurl.dll.a /usr/local/lib/libcurl.dll.a libtool: install: base_file=`basename libcurl.la` libtool: install: dlpath=`/bin/sh 2>&1 -c '. .libs/'libcurl.la'i; echo libcurl-4.dll'` libtool: install: dldir=/usr/local/lib/`dirname ../bin/libcurl-4.dll` libtool: install: test -d /usr/local/lib/../bin || mkdir -p /usr/local/lib/../bin libtool: install: /bin/install -c .libs/libcurl-4.dll /usr/local/lib/../bin/libcurl-4.dll libtool: install: chmod a+x /usr/local/lib/../bin/libcurl-4.dll libtool: install: if test -n '' && test -n 'strip --strip-unneeded'; then eval 'strip --strip-unneeded /usr/local/lib/../bin/libcurl-4.dll' || exit 0; fi libtool: install: /bin/install -c .libs/libcurl.lai /usr/local/lib/ libcurl.la libtool: install: /bin/install -c .libs/libcurl.a /usr/local/lib/libcurl.a libtool: install: chmod 644 /usr/local/lib/libcurl.a libtool: install: ranlib /usr/local/lib/libcurl.a ---------------------------------------------------------------------- Libraries have been installed in: /usr/local/lib If you ever happen to want to link against installed libraries in a given directory, LIBDIR, you must either use libtool, and specify the full pathname of the library, or use the `-LLIBDIR' flag during linking and do at least one of the following: - add LIBDIR to the `PATH' environment variable during execution - add LIBDIR to the `LD_RUN_PATH' environment variable during linking - use the `-LLIBDIR' linker flag ... /bin/install -c -m 644 'curl.h' '/usr/local/include/curl/curl.h' /bin/install -c -m 644 'curlver.h' '/usr/local/include/curl/curlver.h' /bin/install -c -m 644 'easy.h' '/usr/local/include/curl/easy.h' /bin/install -c -m 644 'mprintf.h' '/usr/local/include/curl/mprintf.h' /bin/install -c -m 644 'stdcheaders.h' '/usr/local/include/curl/stdcheaders.h' /bin/install -c -m 644 'types.h' '/usr/local/include/curl/types.h' /bin/install -c -m 644 'multi.h' '/usr/local/include/curl/multi.h' /bin/install -c -m 644 'typecheck-gcc.h' '/usr/local/include/curl/typecheck-gcc.h' /bin/install -c -m 644 'curlbuild.h' '/usr/local/include/curl/curlbuild.h' /bin/install -c -m 644 'curlrules.h' '/usr/local/include/curl/curlrules.h' ... 8. $ which curl && curl /usr/local/bin/curl curl: try 'curl --help' for more information I have following files in C:\temp\msys\1.0\local\bin\ (/usr/local/bin in Unix-scheme): 02.02.2009 15:10 4 029 curl-config 02.02.2009 15:10 98 591 curl.exe 02.02.2009 15:09 262 934 libcurl-4.dll In /usr/local/include/curl ten includes: 02.02.2009 15:10 67 183 curl.h 02.02.2009 15:10 5 865 curlbuild.h 02.02.2009 15:10 7 478 curlrules.h 02.02.2009 15:10 2 799 curlver.h 02.02.2009 15:10 3 526 easy.h 02.02.2009 15:10 2 850 mprintf.h 02.02.2009 15:10 13 039 multi.h 02.02.2009 15:10 1 383 stdcheaders.h 02.02.2009 15:10 33 337 typecheck-gcc.h 02.02.2009 15:10 15 types.h ---- Sorry for many details, but now I can show the wrong behaviour of the haskell bindings for cURL under windows: 9. curl-1.3.4 is taken from hackage and unzipped to /home/Kuznetsov $ cd ~/curl-1.3.4 $ runhaskell Setup.hs configure --extra-include-dirs=/usr/local/include --extra-lib-dirs=/usr/local/lib Configuring curl-1.3.4... $ runhaskell Setup.hs build Preprocessing library curl-1.3.4... Building curl-1.3.4... [1 of 8] Compiling Network.Curl.Debug ( Network\Curl\Debug.hs, dist\build\Network\Curl\Debug.o ) [2 of 8] Compiling Network.Curl.Types ( Network\Curl\Types.hs, dist\build\Network\Curl\Types.o ) [3 of 8] Compiling Network.Curl.Post ( Network\Curl\Post.hs, dist\build\Network\Curl\Post.o ) [4 of 8] Compiling Network.Curl.Opts ( Network\Curl\Opts.hs, dist\build\Network\Curl\Opts.o ) [5 of 8] Compiling Network.Curl.Code ( Network\Curl\Code.hs, dist\build\Network\Curl\Code.o ) [6 of 8] Compiling Network.Curl.Info <http://network.curl.info/> ( Network\Curl\Info.hs, dist\build\Network\Curl\Info.o ) Network\Curl\Info.hs:80:0: Warning: Defined but not used: `stringTag' Network\Curl\Info.hs:83:0: Warning: Defined but not used: `longTag' Network\Curl\Info.hs:86:0: Warning: Defined but not used: `doubleTag' Network\Curl\Info.hs:89:0: Warning: Defined but not used: `slistTag' [7 of 8] Compiling Network.Curl.Easy ( Network\Curl\Easy.hs, dist\build\Network\Curl\Easy.o ) [8 of 8] Compiling Network.Curl ( Network\Curl.hs, dist\build\Network\Curl.o ) C:\Program Files\Haskell\bin\ar.exe: creating dist\build\libHScurl-1.3.4.a $ runhaskell Setup.hs install Installing library in C:\Program Files\Haskell\curl-1.3.4\ghc-6.10.1 Registering curl-1.3.4... Reading package info from "dist\\installed-pkg-config" ... done. Writing new package config file... done. 10. In package.conf I have seen: InstalledPackageInfo {package = PackageIdentifier {pkgName = PackageName "curl", pkgVersion = Version {versionBranch = [1,3,4], versionTags = []}}, license = BSD3, copyright = "", maintainer = "Sigbjorn Finne < sigbjorn.finne(a)gmail.com>", author = "Sigbjorn Finne", stability = "", homepage = "", pkgUrl = "", description = "libcurl is a client-side URL transfer library, supporting FTP, FTPS, HTTP,\nHTTPS, SCP, SFTP, TFTP, TELNET, DICT, LDAP, LDAPS and FILE.\nlibcurl supports SSL certificates, HTTP POST, HTTP PUT, FTP uploading,\nHTTP form based upload, proxies, cookies, user+password authentication\n(Basic, Digest, NTLM, Negotiate, Kerberos4), file transfer resume,\nhttp proxy tunneling and more!\n\nThis package provides a Haskell binding to libcurl.", category = "Network", exposed = True, exposedModules = ["Network.Curl","Network.Curl.Code"," Network.Curl.Info <http://network.curl.info/>","Network.Curl.Opts","Network.Curl.Post","Network.Curl.Types","Network.Curl.Easy","Network.Curl.Debug"], hiddenModules = [], importDirs = ["C:\\Program Files\\Haskell\\curl-1.3.4\\ghc-6.10.1"], libraryDirs = ["C:\\Program Files\\Haskell\\curl-1.3.4\\ghc-6.10.1","C:/temp/msys/1.0/local/lib"], hsLibraries = ["HScurl-1.3.4"], extraLibraries = ["curl"], extraGHCiLibraries = [], includeDirs = ["C:/temp/msys/1.0/local/include"], includes = [], depends = [PackageIdentifier {pkgName = PackageName "base", pkgVersion = Version {versionBranch = [3,0,3,0], versionTags = []}},PackageIdentifier {pkgName = PackageName "bytestring", pkgVersion = Version {versionBranch = [0,9,1,4], versionTags = []}},PackageIdentifier {pkgName = PackageName "containers", pkgVersion = Version {versionBranch = [0,2,0,0], versionTags = []}}], hugsOptions = [], ccOptions = [], ldOptions = [], frameworkDirs = [], frameworks = [], haddockInterfaces = ["C:\\Program Files\\Haskell\\doc\\curl-1.3.4\\html\\curl.haddock"], haddockHTMLs = ["C:\\Program Files\\Haskell\\doc\\curl-1.3.4\\html"]} In "C:\Program Files\Haskell\curl-1.3.4\ghc-6.10.1\" I have seen HScurl-1.3.4.o , libHScurl-1.3.4.a and other Curl files. 11. Final tests: under msys: $ ghci Prelude> :m Network.Curl module `Network.Curl' is not loaded Bad, but not a disaster. under windows: C:\> ghci GHCi, version 6.10.1: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer ... linking ... done. Loading package base ... linking ... done. Prelude> :m Network.Curl Prelude Network.Curl> let a = curlGet Loading package syb ... linking ... done. Loading package base-3.0.3.0 ... linking ... done. Loading package array-0.2.0.0 ... linking ... done. Loading package containers-0.2.0.0 ... linking ... done. Loading package bytestring-0.9.1.4 ... linking ... done. Loading package curl-1.3.4 ... <interactive>: curl: Не найден указанный модуль. (text in russian here because of localized Vista. The message is near "Can't load specified module") can't load .so/.DLL for: curl (addDLL: could not load DLL) Prelude Network.Curl> So, the question is why curl doesn't work? I tried to use Cabal but it failed with building too. How can I test the fact that C:\temp\msys\1.0\local\bin\libcurl-4.dll is used in curl-1.3.4 ? -- Iliya Kuznetsov +7-916-878-75-70 -- Iliya Kuznetsov +7-916-878-75-70

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build problems on Hackage
by Wolfgang Jeltsch 05 Feb '09

05 Feb '09

Hello all, alas, I couldn’t found any information about who is responsible for the build system on Hackage. So I address this issue to all of you. type-level built fine with GHC 6.8 but failed to build with GHC 6.10. The last line of the build log is this: > haddock: internal Haddock or GHC error: Maybe.fromJust: Nothing The complete log is at <http://tinyurl.com/as67x5>. This problem has the unfortunate consequence that type-equality-check cannot be built since it depends on type-level and nowadays only GHC 6.10 seems to be used for building packages on Hackage. This, in turn, will make almost all Grapefruit packages unbuildable when they are released (which is expected to happen soon). This, in turn, means almost no Grapefruit documentation on Hackage which, I think, would be very bad. So could someone please take the time and fix this problem soon? Thank you in advance. Best wishes, Wolfgang

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RE: Define variable types
by Tsunkiet Man 05 Feb '09

05 Feb '09

Hello, thank you guys for your responds. I got it working now =). Thanks a lot! Greetx JTKM

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