February 2009 - Haskell-Cafe

ANN: regex-posix-unittest-1.0 AND regex-posix-0.94.1 AND regex-tdfa-0.97.1
by ChrisK 02 Feb '09

02 Feb '09

I have three announcements to make about regex-* related packages. The regex-posix-0.94.1 package update provides better semantics for multiple matches. Below version 0.94, if any match was empty the matching would stop. Now the empty match is returned and the position is incremented and the searching continues. The regex-tdfa-0.71.1 package update provides the same new multiple match semantics. It also fixes a bug I found. I know of no outstanding bugs in regex-tdfa, and version 0.71.1 now passes all the tests used in regex-posix-unittest-1.0 announced below. We should care about the correctness of our operating system libraries. To help with this, I have a NEW package to announce: regex-posix-unittest-1.0 The accompanying wiki page is http://www.haskell.org/haskellwiki/Regex_Posix This new package provides an executable called regex-posix-unittest which you can install as --user or --global. The regex-posix-unittest executable with no arguments runs a suite of unit tests, all of which are described by text files in the package, the format is documented in the wiki page. By editing the text files in the package you can add to or delete from the unit tests being run. With two arguments the program expects the text first and the pattern second and will run just that match and print all the results. How does regex-posix-unittest help us care about the OS libraries? The regex-posix distributed in the GHC bundle uses the OS C library's "regex.h" API. The regex-posix-unittest package will quite likely show you that your OS C library "regex.h" API is full of bugs. If you are on Linux, it will show you a plethora of GLIBC bugs in Posix conformance. If you are on OS X, FreeBSD, or NetBSD, it will show you many bugs including a critical bug where it fail to find a match where one actually exists. These bugs in the OS library are inherited by your "sed" program as well as regex-posix and Haskell. If you are on Windows, or OpenBSD, or Solaris, or anything else, then please update the wiki page at http://www.haskell.org/haskellwiki/Regex_Posix or email me with your results so I can update the wiki. You may have evil and ingenious tests of Posix extended regular expressions to add to the test suite. Adding them is easy and if you send them to me I will put them in an updated version of regex-posix-unittest. Cheers, Chris

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System.Posix.Files.isDirectory and System.Posix.Files.isSymbolicLink
by Erik de Castro Lopo 02 Feb '09

02 Feb '09

Hi all, The following code creates a symbolic link in the current directory and then uses System.Posix.Files.getFileStatus to get the status of the link. However, isDirectory returns True and isSymbolicLink returns False which is very different from what the stat() system call on a POSIX system would return. I consider this a bug. I'm using ghc-6.8.2. Has this been fixed in a later version? Cheers, Erik module Main where import qualified System.Directory import qualified System.Posix.Files main :: IO () main = do let linkName = "tmp-link" cwd <- System.Directory.getCurrentDirectory System.Posix.Files.createSymbolicLink "/tmp" linkName stat <- System.Posix.Files.getFileStatus linkName if System.Posix.Files.isDirectory stat then putStrLn "Is a directory?????" else putStrLn "Not a directory." if System.Posix.Files.isSymbolicLink stat then putStrLn "Is a symlink" else putStrLn "Not a symlink?????" -- ----------------------------------------------------------------- Erik de Castro Lopo ----------------------------------------------------------------- "Anyone who considers arithmetical methods of producing random digits is, of course, in a state of sin." - John Von Neumann (1951)

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ICFP09 Final CFP
by Matthew Fluet (ICFP Publicity Chair) 02 Feb '09

02 Feb '09

Final Call for Papers ICFP 2009: International Conference on Functional Programming Edinburgh, Scotland, 31 August - 2 September 2009 http://www.cs.nott.ac.uk/~gmh/icfp09.html ** Submission deadline: 2 March 2009 ** Submission URL: https://www.softconf.com/a/icfp09/ ICFP 2009 seeks original papers on the art and science of functional programming. Submissions are invited on all topics from principles to practice, from foundations to features, from abstraction to application. The scope includes all languages that encourage functional programming, including both purely applicative and imperative languages, as well as languages with objects or concurrency. Particular topics of interest include * Language Design * Implementation * Software-Development Techniques * Foundations * Applications and Domain-Specific Languages * Functional Pearls The conference also solicits Experience Reports, which are short papers that provide evidence that functional programming really works or describe obstacles that have kept it from working in a particular application. Important Dates (at 20:00 UTC) ~~~~~~~~~~~~~~~ Submission: 2 March 2009 https://www.softconf.com/a/icfp09/ Author response: 21-23 April 2009 Notification: 5 May 2009 Final papers due: 8 June 2009 Call for Papers (full text) ~~~~~~~~~~~~~~~ http://web.cecs.pdx.edu/~apt/icfp09_cfp.html Call for Experience Reports (full text) ~~~~~~~~~~~~~~~~~~~~~~~~~~~ http://web.cecs.pdx.edu/~apt/icfp09_cfer.html Program Chair ~~~~~~~~~~~~~ Andrew Tolmach Department of Computer Science Portland State University P.O. Box 751, Portland, OR 97207 USA Email: apt(a)cs.pdx.edu Phone: +1 503 725 5492 Fax: +1 503 725 3211 Mail sent to the address above is filtered for spam. If you send mail and do not receive a prompt response, particularly if the deadline is looming, feel free to telephone.

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UDP
by Andrew Coppin 02 Feb '09

02 Feb '09

I'm trying to write a simple program that involves UDP. I was hoping something like this would work: module Main where import Network.Socket main = withSocketsDo main2 main2 = do s <- socket AF_INET Datagram defaultProtocol putStrLn "Waiting..." x <- recv s 100 putStrLn x Unfortunately, that doesn't work at all. It immediately throws an exception ("unknown error"). But then, the whole module seems to be completely undocumented. I managed to find a tiny amount of info online about the underlying C API, but I still don't get how the Haskell interface is supposed to be used. Any hints?

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cURL under Windows again
by Iliya Kuznetsov 02 Feb '09

02 Feb '09

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 ( 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","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

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Haskeline, pcre-light, iconv and Cabal on OSX
by Antoine Latter 02 Feb '09

02 Feb '09

Funny story, If I do the following three things, I get errors on my Intel Mac OS 10.5: * Build an executable with Cabal * Have the executable have a build-dep of pcre-light in the .cabal * use haskeline in the executable itself I get crazy linker errors relating to haskeline and libiconv: Shell output: >>>>> $ cabal clean && cabal configure && cabal build cleaning... Configuring test-0.0.0... Preprocessing executables for test-0.0.0... Building test-0.0.0... [1 of 1] Compiling Main ( test.hs, dist/build/test/test-tmp/Main.o ) Linking dist/build/test/test ... Undefined symbols: "_iconv_open", referenced from: _s9Qa_info in libHShaskeline-0.6.0.1.a(IConv.o) "_iconv_close", referenced from: _iconv_close$non_lazy_ptr in libHShaskeline-0.6.0.1.a(IConv.o) "_iconv", referenced from: _sa0K_info in libHShaskeline-0.6.0.1.a(IConv.o) ld: symbol(s) not found collect2: ld returned 1 exit status <<<<< But all three above conditions need to be true - if I build using 'ghc --make' everything works great, even if the executable imports pcre-light and haskeline. If I have build-deps on haskeline and pcre-light, but don't actually import haskeline, everything also works great. Here are the files I've used: test.hs: >>>>> import System.Console.Haskeline main :: IO () main = print "Hello!" <<<<< test.cabal >>>>> Name: test version: 0.0.0 cabal-version: >= 1.2 build-type: Simple Executable test main-is: test.hs build-depends: base, haskeline, pcre-light>=0.3 <<<<< Is there some way I need to be building haskeline on OS X to make this work? Thanks, Antoine more details: >>>>> $ cabal --version cabal-install version 0.6.0 using version 1.6.0.1 of the Cabal library <<<<< >>>>> $ ghc --version The Glorious Glasgow Haskell Compilation System, version 6.10.0.20081007 <<<<< links: pcre-light: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/pcre-light haskeline: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/haskeline

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cabal list can't find Glob.cabal file?
by Dougal Stanton 02 Feb '09

02 Feb '09

I get a curious message when trying to run 'cabal list': $ cabal list ....omit some lines... ...................... Latest version available: 0.3 Category: Network Synopsis: Pure bindings for the MaxMind IP database. License: OtherLicense cabal: Couldn't read cabal file "./Glob/0.1/Glob.cabal" Any ideas? As far as Hackage and the local index are concerned, 0.1 isn't even a recent version of Glob. Why should it be looking for the file? cabal-install version 0.5.1 using version 1.4.0.1 of the Cabal library -- Dougal Stanton dougal(a)dougalstanton.net // http://www.dougalstanton.net

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Re: [Haskell-cafe] pure crisis :)
by Sergey Zaharchenko 02 Feb '09

02 Feb '09

Hello Bulat! Sun, Feb 01, 2009 at 10:19:18PM +0300 you wrote: > Hello haskell-cafe, > pure functional denotation for crisis: > (_|_) Thus, when people try to evaluate the amount of savings they have left, their behavior frequently becomes _undefined_ :) -- DoubleF

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Network.UrlDisp
by Pieter Laeremans 02 Feb '09

02 Feb '09

Hello, Has anyone some exampe usages of : Network.UrlDisp ? thanks in advance, Pieter -- Pieter Laeremans <pieter(a)laeremans.org>

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Newtype deriving with functional dependencies
by Louis Wasserman 01 Feb '09

01 Feb '09

Is there any sensible way to make newtype FooT m e = FooT (StateT Bar m e) deriving (MonadState) work to give instance MonadState Bar (FooT m e)? That is, I'm asking if there would be a semantically sensible way of modifying GeneralizedNewtypeDeriving to handle multi-parameter type classes when there is a functional dependency involved, assuming by default that the newtype is the more general of the types, perhaps? Louis Wasserman wasserman.louis(a)gmail.com

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