March 2009 - Glasgow-haskell-users

Int vs Word performance?
by Marco Túlio Gontijo e Silva 27 Mar '09

27 Mar '09

Hello, sorry for breaking the thread, I just got in the list. Simon Peyton-Jones simonpj at microsoft.com : > PS: in the case that no one gets around to creating such a patch, > creating a ticket that documents the problem and points to the needed > specialisations would be a start Was this created? I could not find something about it in the GHC trac. Greetings. -- marcot http://marcot.iaaeee.org/

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Under OS X 10.5.6: GHC 6.10.1 Release Candidate 1
by Gregory Wright 27 Mar '09

27 Mar '09

I built ghc-6.10.1.20090314 on OS X 10.5.6 (Intel) using ghc 6.8.2 as a bootstrap compiler. The build was done using the MacPorts infrastructure. Summary test results: OVERALL SUMMARY for test run started at Tue Mar 17 15:31:38 EDT 2009 2334 total tests, which gave rise to 12487 test cases, of which 0 caused framework failures 2460 were skipped 9709 expected passes 258 expected failures 0 unexpected passes 60 unexpected failures Unexpected failures: 2469(ghci) apirecomp001(normal) bits (normal ,optc,hpc,optasm,profc,profasm,ghci,threaded1,threaded2,profthreaded) conc049(hpc) conc068(normal) derefnull(profc,profthreaded) divbyzero(profc,profthreaded) genUpTo (normal ,optc,hpc,optasm,profc,profasm,ghci,threaded1,threaded2,profthreaded) length001(optc,hpc,optasm,profc,profasm,threaded2,profthreaded) num009 (normal ,optc,hpc,optasm,profc,profasm,ghci,threaded1,threaded2,profthreaded) num012 (normal ,optc,hpc,optasm,profc,profasm,ghci,threaded1,threaded2,profthreaded) signals002(ghci) signals004(ghci,threaded1,threaded2,profthreaded) I haven't looked at the errors in detail, but generally the release candidate seems OK. BTW, a test target will be added to MacPorts's portfile for the 6.10.2 release, which will let you run the test suite by typing > sudo port test ghc and if you then install the tested build, a record of the test will be saved in $PREFIX/share/ghc-<version>/. Best Wishes, Greg

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compilation of pattern-matching?
by Claus Reinke 27 Mar '09

27 Mar '09

I just noticed that GHC (6.11.20090320) seems to compile both f (a:b:c) = f (a:[]) = f [] = and f [] = f (a:[]) = f (a:b:c) = to something like (looking at Core, but writing source) f x = case x of { [] -> ..; (a:t) -> case t of { [] ->..; (b:c) ->..}} That doesn't seem right to me: if I try to give the patterns in the order from frequent to rare, in order to reduce jumps, I don't expect GHC to rearrange things. What is the rationale for this? And where can I read about GHC's pattern match compilation approach in general? Claus

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Really bad code for single method dictionaries?
by Jason Dusek 27 Mar '09

27 Mar '09

I was reading the stream fusion code today and came across a comment stating that single element dictionaries interacted poorly with GHC's optimizer: class Unlifted a where [...] expose [...] -- | This makes GHC's optimiser happier; it sometimes produces really bad -- code for single-method dictionaries -- unlifted_dummy [...] A cursory search on GHC's Trac shows no corresponding bug; is this no longer a problem? A small problem? I would like to know more about it. -- Jason Dusek |...stream fusion code...| http://www.cse.unsw.edu.au/~dons/code/streams/list/Data/Stream.hs

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Problem with a second installed version of the syb package
by José Pedro Magalhães 26 Mar '09

26 Mar '09

Hello all, I mentioned this problem before on IRC and remember this might have had something to do with syb having been unversioned in the release of GHC 6.10.1. However, I've tested this under 6.10.2-rc1 and the problem is still there. Concretely, the problem is: I've developed a sucessor package to syb-0.1.0.0. I can install it with runghc Setup.hs install. However, after having installed it I can't use it, getting this error when loading any module that imports Data.Generics: Bad interface file: C:\Program Files (x86)\Haskell\syb-0.2.0.0\ghc-6.10.1\Data\Generics.hi Something is amiss; requested module syb:Data.Generics differs from name found in the interface file syb-0.2.0.0:Data.Generics Failed, modules loaded: none. What is the problem here? Thanks, Pedro

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Can't get editline support to work in 6.10.1
by Devon Tucker 26 Mar '09

26 Mar '09

Hello, I recently compiled and installed GHC 6.10.1 on Ubuntu 8.10 64-bit, after having installed 6.8 from the repositories. However when I launched ghci I discovered that the arrow keys and backspace did not work! After some quick googling I came to the conclusion that editline support was not enabled. I installed any package I could find named libedit*-dev and configured and compiled GHC again. Still no luck. Looking at my configure output I see a line like this (paraphrased, I don't have the output in front of me right now): Checking for ghc editline package... no. I really don't know what to do now. I have installed 6.10.1 on almost identical setups without any problem and I find ghci to be totally unproductive without command history and tab-completion. Any help would be greatly appreciated. Cheers, Devon Tucker

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strace breaks cabal - how to find the problem?
by Robin Green 25 Mar '09

25 Mar '09

On my obscure configuration (GHC 6.10.1, with pkgenv activated, on Fedora Linux rawhide running on a VirtualBox x86 VM with hardware virtualisation enabled), running strace on cabal causes it to misbehave, as described below. I don't know whether this is due to a bug in cabal, the GHC runtime, strace, the Linux kernel, VirtualBox, or my processor's virtualization support. Not sure how to proceed to debug this. Perhaps someone else could try this, on their configuration, and report what they find? This command is ran in an untarred copy of hs-bibutils 0.1 (not that it matters): strace -f -e trace=file cabal install --extra-include-dirs=../bibutils_4.1/lib/ 2>&1|cat >cabal.strace Cabal fails to determine the version of ghc-pkg (or sometimes ghc), and stops, complaining that it can't verify that the version of ghc(-pkg) is the required one. ghc-pkg is execve'd, but something goes wrong - not sure what. -- Robin

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ANNOUNCE: GHC 6.10.2 Release Candidate 1
by Ian Lynagh 25 Mar '09

25 Mar '09

We are pleased to announce the first release candidate for GHC 6.10.2: http://www.haskell.org/ghc/dist/6.10.2-rc1/ This includes two source bundles: ghc-6.10.1.20090314-src.tar.bz2 ghc-6.10.1.20090314-src-extralibs.tar.bz2 Only the first of these is necessary. The "extralibs" package contains various extra packages that we normally supply with GHC - unpack the extralibs tarball on top of the source tree to add them, and they will be included in the build automatically. There are also installers for Windows (i386) and OS X (i386), and binary distributions for x86_64/Linux and i386/Linux. More may appear later. Please test as much as possible; bugs are much cheaper if we find them before the release! Thanks Ian, on behalf of the GHC team

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Re: [Haskell-cafe] GHC 6.10.2 - PCap package - affected by the change of Finalizers?
by Bulat Ziganshin 24 Mar '09

24 Mar '09

Hello Neil, Tuesday, March 24, 2009, 9:08:08 PM, you wrote: one more case > Looks like pcap package needs a little tweek for 6.10.2 - programs > compiled with it bomb out with > ......error: a C finalizer called back into Haskell. > use Foreign.Concurrent.newForeignPtr for Haskell finalizers. > Is my interpretation of this error message correct? > Cheers > Neil > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe(a)haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com

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Puzzling (to me) type error message
by Colin Adams 24 Mar '09

24 Mar '09

I'm trying out concurrent haskell (never mind that the code isn't actually very concurrent - I'm just trying to get things to compile first). So with the following code, I get: play_move :: IORef Game_state -> IO () play_move game_state_ior = do (_, state, _) <- readIORef game_state_ior putStr "Playing AI: " start_time <- getCurrentTime ai_in_channel <- newChan ai_out_channel <- newChan writeChan ai_in_channel state ai_thread_id <- forkIO (run_ai ai_in_channel ai_out_channel) move <- readChan ai_out_channel end_time <- move `seq` (modifyIORef game_state_ior $! update_interactive_from_move move) >> getCurrentTime putStrLn $ show $ (diffUTCTime end_time start_time) run_ai :: Chan Non_interactive_state -> Chan Move.Move -> IO () run_ai in_channel out_channel = do state <- readChan in_channel let move = recommended_move state writeChan out_channel move UI.hs:625:45: Not in scope: type constructor or class `Move.Move' If I then comment-out the type signature for run_ai, it compiles fine with the following warning message: UI.hs:626:0: Warning: Definition but no type signature for `run_ai' Inferred type: run_ai :: Chan Non_interactive_state -> Chan Move.Move -> IO () Ghc 6.10.1 on Mac OS X. What is going on?

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