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build fails due to sem_close...
by Jiri Skala 15 Apr '11

15 Apr '11

Hi all, I've got error listed below when I've tried to build ghc-7.0.2 on ppc64 arch. I 've tested patch from Debian (-pthread option) but this didn't fix the issue. Any idea what's wrong? Thanks for any tip/help. Jiri used packages: glibc: 2.12.90, 2.13.90 (tested for both) gcc: 4.6.0 I use these options for ppc64 arch in build.mk %ifarch ppc64 GhcUnregisterised=YES GhcWithNativeCodeGen=NO SplitObjs=NO GhcWithInterpreter=NO GhcNotThreaded=YES SRC_HC_OPTS+=-optc-mminimal-toc SRC_CC_OPTS+=-mminimal-toc -Wa,--noexecstack %endif error log: configure: Building in-tree ghc-pwd /usr/bin/ld: /usr/lib64/ghc-7.0.2/unix-2.4.2.0/libHSunix-2.4.2.0.a(Semaphore.o): undefined reference to symbol 'sem_close@@GLIBC_2.3' /usr/bin/ld: note: 'sem_close@@GLIBC_2.3' is defined in DSO /lib64/libpthread.so.0 so try adding it to the linker command line /lib64/libpthread.so.0: could not read symbols: Invalid operation collect2: ld returned 1 exit status configure: error: Building ghc-pwd failed

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Programming Chalenges: The 3n+1 problem
by Dmitri O.Kondratiev 15 Apr '11

15 Apr '11

3n+1 is the first, "warm-up" problem at Programming Chalenges site: http://www.programming-challenges.com/pg.php?page=downloadproblem&probid=11… (This problem illustrates Collatz conjecture: http://en.wikipedia.org/wiki/3n_%2B_1#Program_to_calculate_Collatz_sequences ) As long as the judge on this site takes only C and Java solutions, I submitted in Java some add-hock code (see at the end of this message) where I used recursion and a cache of computed cycles. Judge accepted my code and measured 0.292 sec with best overall submissions of 0.008 sec to solve the problem. *** Question: I wonder how to implement cache for this problem in Haskell? At the moment, I am not so much interested in the speed of the code, as in nice implementation. To illustrate my question I add the problem description and my Java solution at the end of this message. Thanks! *** Problem Consider the following algorithm to generate a sequence of numbers. Start with an integer *n*. If *n* is even, divide by 2. If *n* is odd, multiply by 3 and add 1. Repeat this process with the new value of *n*, terminating when *n* = 1. For example, the following sequence of numbers will be generated for *n* = 22: 22 11 34 17 52 26 13 40 20 10 5 16 8 4 2 1 It is *conjectured* (but not yet proven) that this algorithm will terminate at *n* = 1 for every integer *n*. Still, the conjecture holds for all integers up to at least 1, 000, 000. For an input *n*, the *cycle-length* of *n* is the number of numbers generated up to and *including* the 1. In the example above, the cycle length of 22 is 16. Given any two numbers *i* and *j*, you are to determine the maximum cycle length over all numbers between *i* and *j*, *including* both endpoints. InputThe input will consist of a series of pairs of integers *i* and *j*, one pair of integers per line. All integers will be less than 1,000,000 and greater than 0. OutputFor each pair of input integers *i* and *j*, output *i*, *j* in the same order in which they appeared in the input and then the maximum cycle length for integers between and including *i* and *j*. These three numbers should be separated by one space, with all three numbers on one line and with one line of output for each line of input. Sample Input 1 10 100 200 201 210 900 1000 Sample Output 1 10 20 100 200 125 201 210 89 900 1000 174 *** my Java solution import java.io.BufferedReader; import java.io.InputStreamReader; public class Main { final static BufferedReader reader_ = new BufferedReader(new InputStreamReader(System.in)); /** * @param args */ public static void main(String[] args) { new Problem().run(); } static String[] ReadLn() { String[] tokens = null; try { String line = reader_.readLine(); String REGEX_WHITESPACE = "\\s+"; String cleanLine = line.trim().replaceAll(REGEX_WHITESPACE, " "); tokens = cleanLine.split(REGEX_WHITESPACE); } catch (Exception e) {} return tokens; } } class Problem implements Runnable { long CACHE_SIZE = 65536; private final long[] cache_ = new long[(int) CACHE_SIZE]; /** * Compute cycle length for a single number * * @param n number for which we find cycle length * @return cycle length */ long cycleLen(long n) { long len = 1; if (n != 1) { len = getFromCache(n); if (len == 0) { //not yet in cache // Recursively compute and store all intermediate values of cycle length if ((n & 1) == 0) { len = 1 + cycleLen(n >> 1); } else { len = 1 + cycleLen(n * 3 + 1); } putInCache(n, len); } } return len; } void putInCache(long n, long len) { if(n < CACHE_SIZE) { cache_[(int)n] = len; } } long getFromCache(long n) { long result = 0; if(n < CACHE_SIZE) { result = cache_[(int)n]; } return result; } /** * Find max cycle on interval * * @param from interval start * @param to interval end * @return max cycle */ Long maxCycle(Long from, Long to) { Long result = 0L; Long cycle = 0L; // Get all values of cycle length on the interval and put these values into a sorted set for (long i = from; i <= to; i++) { cycle = cycleLen(i); if (cycle > result) result = cycle; } return result; } public void run() { String[] tokens = null; long from, to, result = 0; long arg1, arg2 = 0; while ((tokens = Main.ReadLn()) != null) { if (tokens.length == 2) { arg1 = new Long(tokens[0]).longValue(); arg2 = new Long(tokens[1]).longValue(); from = (arg1 <= arg2) ? arg1 : arg2; to = (arg2 >= arg1 ) ? arg2 : arg1; result = maxCycle(from, to); out(arg1+" "+arg2+" "+result); } } } static void out(String msg) { System.out.println(msg); } }

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Problem building qtHaskell
by Øystein Kolsrud 15 Apr '11

15 Apr '11

Hi! I am trying to install qtHaskell on a Windows 7 machine, but I am running into some problems while running the build script. I believe I have followed all the steps stated in the installation instructions, but get errors of this type: Creating library file: ..\bin\libqtc_core.a c:\Prog\Qt\2010.05\qt\lib/libQtUiTools.a(quiloader.o):quiloader.cpp:(.text+0x3c3): undefined reference to `_Unwind_Resume' Can anyone help me figure out what is missing? I have the following versions installed which should meet the requirements: C:\Prog\QTHASK~1.4>g++ --version g++ (GCC) 4.4.3 C:\Prog\QTHASK~1.4>gmake --version GNU Make 3.81 This program built for Windows32 C:\Prog\QTHASK~1.4>ghc --version The Glorious Glasgow Haskell Compilation System, version 7.0.2 Thanks! Best regards, Øystein Kolsrud

2 2

ghc7 bug? associated type + implicit parameters
by Michal Konečný 15 Apr '11

15 Apr '11

Hi, I have stumbled across some strange behaviour in ghc7. The following compiles fine with ghc 6.12.3: {-# LANGUAGE ImplicitParams #-} {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE NoMonomorphismRestriction #-} module Test where class C t where type TF t ttt :: TF t -> t b :: (C t, ?x :: TF t) => t b = ttt ?x but ghc7 says: Could not deduce (?x::TF t) arising from a use of implicit parameter `?x' from the context (C t, ?x::TF t) bound by the type signature for b :: (C t, ?x::TF t) => t at Test.hs:13:1-10 In the first argument of `ttt', namely `?x' In the expression: ttt ?x In an equation for `b': b = ttt ?x Moreover, when I comment out the type declaration for b, it compiles and the inferred type for b is identical to the one in the above program: *Test> :t b b :: (C t, ?x::TF t) => t It feels to me like a bug but I am not entirely confident. Any ideas? Michal -- |o| Michal Konecny <mikkonecny(a)gmail.com> |o| http://www-users.aston.ac.uk/~konecnym/ |o| office: (+42) (0)121 204 3462 |o| PGP key http://www-users.aston.ac.uk/~konecnym/ki.aston -- |o| Michal Konecny <mikkonecny(a)gmail.com> |o| http://www-users.aston.ac.uk/~konecnym/ |o| office: (+42) (0)121 204 3462 |o| PGP key http://www-users.aston.ac.uk/~konecnym/ki.aston -- |o| Michal Konecny <mikkonecny(a)gmail.com> |o| http://www-users.aston.ac.uk/~konecnym/ |o| office: (+42) (0)121 204 3462 |o| PGP key http://www-users.aston.ac.uk/~konecnym/ki.aston

2 1

Experimental 64 bit installer fails
by Andrew Pennebaker 15 Apr '11

15 Apr '11

I downloaded the experimental 64 bit installer for from Haskell Platform<http://hackage.haskell.org/platform/mac.html>. It fails with the message "The installation failed." In case Haskell Platform i386 was interfering, I uninstalled it. But the 64 bit installer still yields "The installation failed." Specs - Haskell Platform 2011.2.0.0-x86_64 installer - Haskell Platform 2011.2.0.0-i386 present - Mac OS X 10.6.7 - MacBook Pro 5,1 /var/log/install.log Apr 14 17:58:38 wonko Installer[18657]: Haskell Platform Installation Log Apr 14 17:58:38 wonko Installer[18657]: Opened from: /Users/andrew/Downloads/Haskell Platform 2011.2.0.0-x86_64.pkg Apr 14 17:58:46 wonko runner[18669]: Administrator authorization granted. Apr 14 17:58:46 wonko Installer[18657]: ================================================================================ Apr 14 17:58:46 wonko Installer[18657]: User picked Standard Install Apr 14 17:58:46 wonko Installer[18657]: Choices selected for installation: Apr 14 17:58:46 wonko Installer[18657]: Upgrade: "Haskell Platform" Apr 14 17:58:46 wonko Installer[18657]: Upgrade: "Glasgow Haskell Compiler" Apr 14 17:58:46 wonko Installer[18657]: Haskell Platform 2011.2.0.0-x86_64.pkg#ghc.pkg : org.haskell.HaskellPlatform.GHC.pkg : 1 Apr 14 17:58:46 wonko Installer[18657]: Upgrade: "Haskell Platform Libraries" Apr 14 17:58:46 wonko Installer[18657]: Haskell Platform 2011.2.0.0-x86_64.pkg#haskell.pkg : org.haskell.HaskellPlatform.Libraries.pkg : 1 Apr 14 17:58:46 wonko Installer[18657]: Haskell Platform 2011.2.0.0-x86_64.pkg#haskellPlatformPostflight.pkg : org.haskell.haskellPlatform.postflight.pkg : 1.0 Apr 14 17:58:46 wonko Installer[18657]: ================================================================================ Apr 14 17:58:46 wonko Installer[18657]: It took 0.00 seconds to summarize the package selections. Apr 14 17:58:46 wonko Installer[18657]: -[IFDInstallController(Private) _buildInstallPlan]: location = file://localhost Apr 14 17:58:46 wonko Installer[18657]: -[IFDInstallController(Private) _buildInstallPlan]: file://localhost/Users/andrew/Downloads/Haskell%20Platform%202011.2.0.0-x86_64.pkg#ghc.pkg Apr 14 17:58:46 wonko Installer[18657]: -[IFDInstallController(Private) _buildInstallPlan]: file://localhost/Users/andrew/Downloads/Haskell%20Platform%202011.2.0.0-x86_64.pkg#haskell.pkg Apr 14 17:58:46 wonko Installer[18657]: -[IFDInstallController(Private) _buildInstallPlan]: file://localhost/Users/andrew/Downloads/Haskell%20Platform%202011.2.0.0-x86_64.pkg#haskellPlatformPostflight.pkg Apr 14 17:58:46 wonko Installer[18657]: Will use PK session Apr 14 17:58:46 wonko Installer[18657]: Starting installation: Apr 14 17:58:46 wonko Installer[18657]: Configuring volume "Wonko" Apr 14 17:58:46 wonko Installer[18657]: Preparing disk for local booted install. Apr 14 17:58:46 wonko Installer[18657]: Free space on "Wonko": 52.51 GB (52508946432 bytes). Apr 14 17:58:46 wonko Installer[18657]: Create temporary directory "/var/folders/N-/N-IxaaKuFae5ik1WKxV6wE+++TI/-Tmp-//Install.18657bWOdda" Apr 14 17:58:46 wonko Installer[18657]: IFPKInstallElement (3 packages) Apr 14 17:58:46 wonko installd[18673]: PackageKit: ----- Begin install ----- Apr 14 17:58:46 wonko installd[18673]: PackageKit: request=PKInstallRequest <3 packages, destination=/> Apr 14 17:58:46 wonko installd[18673]: PackageKit: packages=(\n "PKLeopardPackage <file://localhost/Users/andrew/Downloads/Haskell%20Platform%202011.2.0.0-x86_64.pkg#ghc.pkg>",\n "PKLeopardPackage <file://localhost/Users/andrew/Downloads/Haskell%20Platform%202011.2.0.0-x86_64.pkg#haskell.pkg>",\n "PKLeopardPackage <file://localhost/Users/andrew/Downloads/Haskell%20Platform%202011.2.0.0-x86_64.pkg#haskellPlatformPostflight.pkg>"\n) Apr 14 17:58:47 wonko installd[18673]: PackageKit: Extracting file://localhost/Users/andrew/Downloads/Haskell%20Platform%202011.2.0.0-x86_64.pkg#ghc.pkg (destination=/var/folders/zz/zzzivhrRnAmviuee+++++++++++/Cleanup At Startup/PKInstallSandbox-tmp/Root/Library/Frameworks, uid=0) Apr 14 17:59:06 wonko installd[18673]: PackageKit: Extracting file://localhost/Users/andrew/Downloads/Haskell%20Platform%202011.2.0.0-x86_64.pkg#haskell.pkg (destination=/var/folders/zz/zzzivhrRnAmviuee+++++++++++/Cleanup At Startup/PKInstallSandbox-tmp/Root/Library, uid=0) Apr 14 17:59:12 wonko installd[18673]: PackageKit: Extracting file://localhost/Users/andrew/Downloads/Haskell%20Platform%202011.2.0.0-x86_64.pkg#haskellPlatformPostflight.pkg (destination=/var/folders/zz/zzzivhrRnAmviuee+++++++++++/Cleanup At Startup/PKInstallSandbox-tmp/Root, uid=0) Apr 14 17:59:14 wonko installd[18673]: PackageKit: Shoving /var/folders/zz/zzzivhrRnAmviuee+++++++++++/Cleanup At Startup/PKInstallSandbox-tmp/Root (1 items) to / Apr 14 17:59:16 wonko installd[18673]: PackageKit: Executing script "./postinstall" in /private/tmp/PKInstallSandbox.e59JtF/Scripts/org.haskell.HaskellPlatform.GHC.pkg.k6SuIR Apr 14 17:59:16 wonko installd[18673]: PackageKit: Executing script "./postinstall" in /private/tmp/PKInstallSandbox.e59JtF/Scripts/org.haskell.HaskellPlatform.Libraries.pkg.dWwJo8 Apr 14 17:59:17 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/GLUT-2.1.2.1.conf" ... done. Apr 14 17:59:17 wonko installd[18673]: ./postinstall: GLUT-2.1.2.1: dependency "OpenGL-2.2.3.0-f260c686098842b872fcd761a1de8b56" doesn't exist (ignoring) Apr 14 17:59:17 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/HTTP-4000.1.1.conf" ... done. Apr 14 17:59:17 wonko installd[18673]: ./postinstall: HTTP-4000.1.1: dependency "mtl-2.0.1.0-5b7a9cce5565d8cc8721ba4f95becf1b" doesn't exist (ignoring) Apr 14 17:59:17 wonko installd[18673]: ./postinstall: HTTP-4000.1.1: dependency "network-2.3.0.2-980e23d4d2855583b05d6ed337c0eaed" doesn't exist (ignoring) Apr 14 17:59:17 wonko installd[18673]: ./postinstall: HTTP-4000.1.1: dependency "parsec-3.1.1-d6e895e0dfa7aa6990c069c9c9c706bb" doesn't exist (ignoring) Apr 14 17:59:17 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/HUnit-1.2.2.3.conf" ... done. Apr 14 17:59:17 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/OpenGL-2.2.3.0.conf" ... done. Apr 14 17:59:17 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/QuickCheck-2.4.0.1.conf" ... done. Apr 14 17:59:17 wonko installd[18673]: ./postinstall: QuickCheck-2.4.0.1: dependency "mtl-2.0.1.0-5b7a9cce5565d8cc8721ba4f95becf1b" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/cgi-3001.1.7.4.conf" ... done. Apr 14 17:59:18 wonko installd[18673]: ./postinstall: cgi-3001.1.7.4: dependency "mtl-2.0.1.0-5b7a9cce5565d8cc8721ba4f95becf1b" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: cgi-3001.1.7.4: dependency "network-2.3.0.2-980e23d4d2855583b05d6ed337c0eaed" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: cgi-3001.1.7.4: dependency "parsec-3.1.1-d6e895e0dfa7aa6990c069c9c9c706bb" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: cgi-3001.1.7.4: dependency "xhtml-3000.2.0.1-fa3c2d95250480afb9bfb787b25e7398" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/deepseq-1.1.0.2.conf" ... done. Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/fgl-5.4.2.3.conf" ... done. Apr 14 17:59:18 wonko installd[18673]: ./postinstall: fgl-5.4.2.3: dependency "mtl-2.0.1.0-5b7a9cce5565d8cc8721ba4f95becf1b" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/haskell-platform-2011.2.0.0.conf" ... done. Apr 14 17:59:18 wonko installd[18673]: ./postinstall: haskell-platform-2011.2.0.0: dependency "haskell-src-1.0.1.4-1aa2c7df30199d039aa020a6edd80791" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: haskell-platform-2011.2.0.0: dependency "html-1.0.1.2-0cdd616c514cf10f5323f121a96991b6" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: haskell-platform-2011.2.0.0: dependency "mtl-2.0.1.0-5b7a9cce5565d8cc8721ba4f95becf1b" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: haskell-platform-2011.2.0.0: dependency "network-2.3.0.2-980e23d4d2855583b05d6ed337c0eaed" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: haskell-platform-2011.2.0.0: dependency "parallel-3.1.0.1-cecd6f84e9c097c6abc356ad52b80887" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: haskell-platform-2011.2.0.0: dependency "parsec-3.1.1-d6e895e0dfa7aa6990c069c9c9c706bb" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: haskell-platform-2011.2.0.0: dependency "regex-base-0.93.2-ea22834f5565d6f16b2cec3e7a63917a" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: haskell-platform-2011.2.0.0: dependency "regex-compat-0.93.1-bfb1854d3b8f7b71bdd9d0efc565110d" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: haskell-platform-2011.2.0.0: dependency "regex-posix-0.94.4-d6abc61e1702c884e7bba4f3e318dda9" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: haskell-platform-2011.2.0.0: dependency "stm-2.2.0.1-88d46817e31bfcb31467cd8ca2c7850b" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: haskell-platform-2011.2.0.0: dependency "syb-0.3-00d8c06f799942b01364e795b2a54d70" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: haskell-platform-2011.2.0.0: dependency "text-0.11.0.5-efa21e4f4b045cc91adb4295f85c7319" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: haskell-platform-2011.2.0.0: dependency "transformers-0.2.2.0-4bbbfde1fb5c4eb17cdb1963dda698f3" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: haskell-platform-2011.2.0.0: dependency "xhtml-3000.2.0.1-fa3c2d95250480afb9bfb787b25e7398" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: haskell-platform-2011.2.0.0: dependency "zlib-0.5.3.1-7e19941cbd00147a79723e25160ffc8b" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/haskell-src-1.0.1.4.conf" ... done. Apr 14 17:59:18 wonko installd[18673]: ./postinstall: haskell-src-1.0.1.4: dependency "syb-0.3-00d8c06f799942b01364e795b2a54d70" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/html-1.0.1.2.conf" ... done. Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/mtl-2.0.1.0.conf" ... done. Apr 14 17:59:18 wonko installd[18673]: ./postinstall: mtl-2.0.1.0: dependency "transformers-0.2.2.0-4bbbfde1fb5c4eb17cdb1963dda698f3" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/network-2.3.0.2.conf" ... done. Apr 14 17:59:18 wonko installd[18673]: ./postinstall: network-2.3.0.2: dependency "parsec-3.1.1-d6e895e0dfa7aa6990c069c9c9c706bb" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/parallel-3.1.0.1.conf" ... done. Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/parsec-3.1.1.conf" ... done. Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/regex-base-0.93.2.conf" ... done. Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/regex-compat-0.93.1.conf" ... done. Apr 14 17:59:18 wonko installd[18673]: ./postinstall: regex-compat-0.93.1: dependency "regex-posix-0.94.4-d6abc61e1702c884e7bba4f3e318dda9" doesn't exist (ignoring) Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/regex-posix-0.94.4.conf" ... done. Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/stm-2.2.0.1.conf" ... done. Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/syb-0.3.conf" ... done. Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/text-0.11.0.5.conf" ... done. Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/transformers-0.2.2.0.conf" ... done. Apr 14 17:59:18 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/xhtml-3000.2.0.1.conf" ... done. Apr 14 17:59:19 wonko installd[18673]: ./postinstall: Reading package info from "/Library/Haskell/ghc-7.0.2/lib/registrations/zlib-0.5.3.1.conf" ... done. Apr 14 17:59:19 wonko installd[18673]: ./postinstall: ln: /Library/Haskell/ghc-7.0.2/doc/ghc-doc: File exists Apr 14 17:59:19 wonko installd[18673]: ./postinstall: ln: /Library/Haskell/ghc-7.0.2/doc/ghc-api: File exists Apr 14 17:59:19 wonko installd[18673]: PackageKit: Install Failed: PKG: post-install scripts for "org.haskell.HaskellPlatform.Libraries.pkg"\nError Domain=PKInstallErrorDomain Code=112 UserInfo=0x102f52820 "An error occurred while running scripts from the package “Haskell Platform 2011.2.0.0-x86_64.pkg”." {\n NSFilePath = "./postinstall";\n NSLocalizedDescription = "An error occurred while running scripts from the package \U201cHaskell Platform 2011.2.0.0-x86_64.pkg\U201d.";\n NSURL = "#haskell.pkg -- file://localhost/Users/andrew/Downloads/Haskell%20Platform%202011.2.0.0-x86_64.pkg";\n PKInstallPackageIdentifier = "org.haskell.HaskellPlatform.Libraries.pkg";\n} Apr 14 17:59:19 wonko Installer[18657]: install:didFailWithError:Error Domain=PKInstallErrorDomain Code=112 UserInfo=0x1002af810 "An error occurred while running scripts from the package “Haskell Platform 2011.2.0.0-x86_64.pkg”." Apr 14 17:59:19 wonko Installer[18657]: Install failed: The Installer encountered an error that caused the installation to fail. Contact the software manufacturer for assistance. Apr 14 17:59:19 wonko Installer[18657]: IFDInstallController 23DC40 state = 7 Apr 14 17:59:19 wonko Installer[18657]: Displaying 'Install Failed' UI. Apr 14 17:59:19 wonko Installer[18657]: 'Install Failed' UI displayed message:'The Installer encountered an error that caused the installation to fail. Contact the software manufacturer for assistance.'. Apr 14 18:02:50 wonko Installer[24606]: @(#)PROGRAM:Install PROJECT:Install-595.1 Apr 14 18:02:50 wonko Installer[24606]: @(#)PROGRAM:Installer PROJECT:Installer-430.1 Apr 14 18:02:50 wonko Installer[24606]: Hardware: MacBookPro5,5 @ 2.53 GHz (x 2), 4096 MB RAM Apr 14 18:02:50 wonko Installer[24606]: Running OS Build: Mac OS X 10.6.7 (10J869) Apr 14 18:02:50 wonko Installer[24606]: Env: PATH=/usr/bin:/bin:/usr/sbin:/sbin Apr 14 18:02:50 wonko Installer[24606]: Env: TMPDIR=/var/folders/N-/N-IxaaKuFae5ik1WKxV6wE+++TI/-Tmp-/ Apr 14 18:02:50 wonko Installer[24606]: Env: SHELL=/bin/bash Apr 14 18:02:50 wonko Installer[24606]: Env: HOME=/Users/andrew Apr 14 18:02:50 wonko Installer[24606]: Env: USER=andrew Apr 14 18:02:50 wonko Installer[24606]: Env: LOGNAME=andrew Apr 14 18:02:50 wonko Installer[24606]: Env: DISPLAY=/tmp/launch-IvsorY/org.x:0 Apr 14 18:02:50 wonko Installer[24606]: Env: SSH_AUTH_SOCK=/tmp/launch-kqVUwk/Listeners Apr 14 18:02:50 wonko Installer[24606]: Env: Apple_PubSub_Socket_Render=/tmp/launch-dpKpq2/Render Apr 14 18:02:50 wonko Installer[24606]: Env: COMMAND_MODE=unix2003 Apr 14 18:02:50 wonko Installer[24606]: Env: __CF_USER_TEXT_ENCODING=0x1F5:0:0 Cheers, Andrew Pennebaker www.yellosoft.us

2 2

Questioning seq
by Andrew Coppin 14 Apr '11

14 Apr '11

A couple of questions: 1. Why is the existence of polymorphic seq bad? 2. Why would the existence of polymorphic rnf be worse? 3. How is pseq different from seq? That is all...

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Type Classes in Haskell - how can I make GHC make a choice of types, when the type chosen doesn't matter?
by Chris Dew 14 Apr '11

14 Apr '11

This is a question about the use of type classes in Haskell. I get an error (below) when trying to compile the code (below and at https://github.com/chrisdew/haskell-sandbox/blob/master/not_working_but_cle… ). As someone just learning Haskell, I have tried following GHC's advice, but I think the cause is different. I believe the problem is that either of the types 'IO String' or plain 'String' could be the type of 'lhello ->> lbracket', but GHC doesn't know which. The problem is that it doesn't matter, either type would work fine. I have posted a working version of the code at https://github.com/chrisdew/haskell-sandbox/blob/master/working_but_ugly.hs . This replaces one of the ->> operators with a new (non type class) operator '->>>' which forces 'lhello ->> lbracket' to be of type 'IO String'. * Is my analysis correct? Or is there something else going on here? * Is there any way of informing GHC what the type of 'lhello ->> lbracket' doen't matter and that is should just chose either of the two possibilities. Or perhaps theres a LANGUAGE option which will let me specify that 'lastest declared matching instance of the class wins' if anything is undecided. Thanks, Chris. Error: chris@chris-linux-desktop:~/nonworkspace/haskell-sandbox$ ghc not_working_but_clean.hs not_working_but_clean.hs:40:16: No instance for (Stream (IO String) (IO String) (IO String) d) arising from a use of `->>' at not_working_but_clean.hs:40:16-34 Possible fix: add an instance declaration for (Stream (IO String) (IO String) (IO String) d) In the first argument of `(->>)', namely `lhello ->> lbracket' In the second argument of `($)', namely `lhello ->> lbracket ->> putStrLn' In a stmt of a 'do' expression: forkIO $ lhello ->> lbracket ->> putStrLn not_working_but_clean.hs:40:16: No instance for (Stream d String (IO ()) (IO ())) arising from a use of `->>' at not_working_but_clean.hs:40:16-47 Possible fix: add an instance declaration for (Stream d String (IO ()) (IO ())) In the second argument of `($)', namely `lhello ->> lbracket ->> putStrLn' In a stmt of a 'do' expression: forkIO $ lhello ->> lbracket ->> putStrLn In the expression: do { forkIO $ (bracket $ hello) ->> putStrLn; forkIO $ lhello ->> lbracket ->> putStrLn; forkIO $ bracket hello ->> putStrLn; forkIO $ lbracket lhello ->> putStrLn; .... } not_working_but_clean.hs: {-# LANGUAGE MultiParamTypeClasses, FlexibleInstances, TypeSynonymInstances, OverlappingInstances #-} {-# OPTIONS_GHC #-} module Main ( main ) where import Control.Concurrent (forkIO, MVar, newEmptyMVar, putMVar, takeMVar, ThreadId, threadDelay) import Control.Monad (forever, liftM) class Stream a b c d where (->>) :: a -> (b -> c) -> d instance Stream (IO d) d (IO c) (IO c) where f ->> g = f >>= g instance Stream d d (IO c) (IO c) where f ->> g = g f instance Stream d d c c where x ->> y = y $ x -- This simply wraps a string in brackets. bracket :: String -> String bracket x = "(" ++ x ++ ")" lbracket :: IO String -> IO String lbracket x = liftM bracket x hello :: String hello = "Hello World!" lhello :: IO String lhello = do return hello main :: IO () main = do forkIO $ (bracket $ hello) ->> putStrLn forkIO $ lhello ->> lbracket ->> putStrLn forkIO $ bracket hello ->> putStrLn forkIO $ lbracket lhello ->> putStrLn threadDelay 10000000 -- Sleep for at least 10 seconds before exiting. working_but_ugly.hs: {-# LANGUAGE MultiParamTypeClasses, FlexibleInstances, TypeSynonymInstances, OverlappingInstances #-} {-# OPTIONS_GHC #-} module Main ( main ) where import Control.Concurrent (forkIO, MVar, newEmptyMVar, putMVar, takeMVar, ThreadId, threadDelay) import Control.Monad (forever, liftM) class Stream a b c d where (->>) :: a -> (b -> c) -> d instance Stream (IO d) d (IO c) (IO c) where f ->> g = f >>= g instance Stream d d (IO c) (IO c) where f ->> g = g f instance Stream d d c c where x ->> y = y $ x x ->>> y = y $ x -- This simply wraps a string in brackets. bracket :: String -> String bracket x = "(" ++ x ++ ")" lbracket :: IO String -> IO String lbracket x = liftM bracket x hello :: String hello = "Hello World!" lhello :: IO String lhello = do return hello main :: IO () main = do forkIO $ (bracket $ hello) ->> putStrLn forkIO $ lhello ->>> lbracket ->> putStrLn forkIO $ bracket hello ->> putStrLn forkIO $ lbracket lhello ->> putStrLn threadDelay 10000000 -- Sleep for at least 10 seconds before exiting.

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Re: [Haskell-cafe] Questioning seq
by Janis Voigtländer 14 Apr '11

14 Apr '11

Am 14.04.2011 18:57:35 schrieb Andrew Coppin<andrewcoppin(a)btinternet.com>: > A couple of questions: > > 1. Why is the existence of polymorphic seq bad? See http://www.iai.uni-bonn.de/~jv/acta.pdf, Sections 1 and 2 and pointers therein. Also, numerous discussions on this list over the years. Best, Janis. > 2. Why would the existence of polymorphic rnf be worse? > > 3. How is pseq different from seq? > > That is all... > -- Jun.-Prof. Dr. Janis Voigtländer http://www.iai.uni-bonn.de/~jv/ mailto:jv@iai.uni-bonn.de

1 0

parallel-haskell mailing list
by Eric Y. Kow 14 Apr '11

14 Apr '11

Hi everybody, I thought I should point out that there is a mailing list dedicated to parallelism and concurrency in Haskell. The group exists to bring together the various groups in the Haskell community that are working on parallelism. It is intended to provide some visibility into the various efforts and to encourage collaboration. So if you want to know what's going on in the parallel Haskell world, this is the place to hang out. You can join the list by sending an email to parallel-haskell%2Bsubscribe(a)googlegroups.com You can also visit the group on the web at http://groups.google.com/group/parallel-haskell Or for those of you who prefer GMane http://dir.gmane.org/gmane.comp.lang.haskell.parallel Enjoy! Eric -- Got news for the Parallel Haskell Digest? Send a mail to eric(a)well-typed.com!

1 0

Munich functional programmers' UG
by "Dr. Heinrich Hördegen" 14 Apr '11

14 Apr '11

Dear all, last week, there have been thoughts to create a user group for functional programmers in Munich, Germany. People who are interessted can join the new mailing list: http://www.fs.lmu.de/cgi-bin/mailman/listinfo/high-order-munich The idea is to have meetings every now and then with talks on aspects of functional programming. However, it's not restricted to Haskell. Please spread the word to anyone who could be interested. Thank you, Heinrich -- hoerdegen(a)funktional.info www.funktional.info --

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