- Glasgow-haskell-users

Strange compilation behavior
by Chad Scherrer 10 Dec '07

10 Dec '07

Hello, I'm using ghc 6.6.1 under Ubuntu Gutsy on a Pentium 4 machine, and I was working to get some code running in an acceptable time. I was surprised to find that turning on profiling switches made the code run over 40x faster! Here's the first run, using ghc --make -O2: 88.03user 0.08system 1:28.16elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+13517minor)pagefaults 0swaps And with ghc --make -O2 -prof -auto-all: 2.33user 0.07system 0:02.41elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+17712minor)pagefaults 0swaps Otherwise everything is the same! Is this something anyone else has run into? I'm not sure if it might have been fixed in 6.8.1, but something funny is going on here. Thanks, Chad

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HUnit 1.2.0.0 on 6.8.1 vs 1.1.1 on 6.6.1
by Greg Fitzgerald 07 Dec '07

07 Dec '07

On Windows, HUnit's assertions are not working - trace below in ghci 6.8.1and 6.6.1. Can others reproduce? Is this the right place to report bugs? Should I confirm a bug here and then create a ticket, create a ticket and that's it, or just mention it here and someone else creates a ticket? GHCi, version 6.8.1: http://www.haskell.org/ghc/ :? for help Loading package base ... linking ... done. > :m Test.HUnit > "abc" @=? "efg" Loading package HUnit-1.2.0.0 ... linking ... done. *** Exception: (unknown) ___ ___ _ / _ \ /\ /\/ __(_) / /_\// /_/ / / | | GHC Interactive, version 6.6.1, for Haskell 98. / /_\\/ __ / /___| | http://www.haskell.org/ghc/ \____/\/ /_/\____/|_| Type :? for help. Loading package base ... linking ... done. > :m Test.HUnit > "abc" @=? "efg" Loading package HUnit-1.1.1 ... linking ... done. *** Exception: user error (HUnit:expected: "abc" but got: "efg") Thanks, Greg

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ANNOUNCE: GHC 6.8.2 Release Candidate
by Ian Lynagh 07 Dec '07

07 Dec '07

We are pleased to announce the Release Candidate phase for GHC 6.8.2. Snapshots beginning with 6.8.1.20071206 are release candidates for 6.8.2 You can download snapshots from here: http://www.haskell.org/ghc/dist/stable/dist/ Right now we have the source bundles: http://www.haskell.org/ghc/dist/stable/dist/ghc-6.8.1.20071206-src.tar.bz2 http://www.haskell.org/ghc/dist/stable/dist/ghc-6.8.1.20071206-src-extralib… Only the first of these is necessary. The "extralibs" package contains various extra packages that are often supplied 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 is also currently an installer for i386/Windows 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! We expect to release in a few days, assuming no major issues are discovered. Thanks Ian, on behalf of the GHC team

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fundeps help
by Ganesh Sittampalam 07 Dec '07

07 Dec '07

Hi, I'm trying to understand what fundeps do and don't let me do. One particular source of confusion is why the following program doesn't typecheck: {-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies #-} module Fundeps where class Dep a b | a -> b, b -> a conv :: (Dep a b1,Dep a b2) => b1 -> b2 conv = id {- end of program -} It seems as if inferring that b1 = b2 is precisely what "improvement" is about, but I'm not really sure when GHC actually applies that. Is there any documentation of that? I've read Mark Jones' paper, the haskell-prime wiki entry about Fundeps and the GHC manual but am still rather lost. Cheers, Ganesh

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Problems building and using ghc-6.9
by Daniel Fischer 06 Dec '07

06 Dec '07

Hi, so today I built ghc-6.9.20071124. First, make died because HsColour version >= 1.8 was needed, couldn't determine the version. I had HsColour 1.6, got myself 1.8, built and installed. make died again, same problem. I added ("v", Version) to the optionTable in HsColour.hs and it worked :) Then I tried to build zlib-0.4.0.1: $ runghc ./Setup.hs configure --user --prefix=$HOME Configuring zlib-0.4.0.1... Setup.hs: At least the following dependencies are missing: base >=2.0&&<2.2 ??? okay, there was something with flag bytestring-in-base, removed that, so that build-depends was base < 2.0 || >= 2.2, bytestring >= 0.9, then $ runghc ./Setup.hs configure --user --prefix=$HOME Configuring zlib-0.4.0.1... Setup.hs: At least the following dependencies are missing: base <2.0||>=2.2, bytestring >=0.9 but: $ ghc-pkg list /home/dafis/lib/ghc-6.9.20071124/package.conf: ALUT-2.1.0.0, Cabal-1.3, GLUT-2.1.1.1, HUnit-1.2.0.0, OpenAL-1.3.1.1, OpenGL-2.2.1.1, QuickCheck-1.1.0.0, array-0.1, base-3.0, bytestring-0.9, cgi-3001.1.5.1, containers-0.1, directory-1.0, fgl-5.4.1.1, filepath-1.1, (ghc-6.9.20071124), haskell-src-1.0.1.1, haskell98-1.0.1, hpc-0.5, html-1.0.1.1, mtl-1.1.0.0, network-2.1.0.0, old-locale-1.0, old-time-1.0, packedstring-0.1, parallel-1.0.0.0, parsec-2.1.0.0, pretty-1.0, process-1.0, random-1.0, readline-1.0.1, regex-base-0.72.0.1, regex-compat-0.71.0.1, regex-posix-0.72.0.2, rts-1.0, stm-2.1.1.0, template-haskell-2.2, time-1.1.2.0, unix-2.2, xhtml-3000.0.2.1 and in stringsearch-0.2: $ runghc ./Setup.lhs configure --user --prefix=$HOME Configuring stringsearch-0.2... Setup.lhs: At least the following dependencies are missing: base -any What's going on?? How can I build packages with ghc-6.9? Or do I have to go back to 6.8.1? Thanks, Daniel

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Re: About -Wall option
by Luis Cabellos 06 Dec '07

06 Dec '07

I think that put signatures is a good practice. I will switch to that. Maybe I preferred to not put signatures because is cooler than other languages type systems :-D Wolfgang Jeltsch wrote: > Inserting all type signatures is definitely best practice. Yitzchak Gale wrote: >My personal style is: >o Put signatures on everything at the top-level >o Inside let and where, only where necessary, BUT:

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RE: C Preprocessor
by Sittampalam, Ganesh 06 Dec '07

06 Dec '07

> > Yes, sure. (although the ' thing doesn't bite us - perhaps it doesn't > > apply with -traditional?) > I think it bit me last week. I had something like: It bites me too - something like this goes wrong with ghc -cpp: #define C(x) x foo' :: foo C(x) Ganesh ============================================================================== Please access the attached hyperlink for an important electronic communications disclaimer: http://www.credit-suisse.com/legal/en/disclaimer_email_ib.html ==============================================================================

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About -Wall option
by Luis Cabellos 05 Dec '07

05 Dec '07

Hi, I have a question, what's the best way to program? - put all the signatures in the Haskell Code? - Only put the type signatures needed to compile (like monomorphism errors or ambiguous signature)? Until now, I prefer the second one, but when I use the -Wall option, there's a lot of complains about type signature. Maybe the type signature is something that not need to be checked as a warning. But if the best practice is to put all the signatures, I found that Cabal generated code need to be fixed, because -Wall complains about it also. -- Thanks, Luis Cabellos,

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Profiling and class methods
by Ravi Nanavati 05 Dec '07

05 Dec '07

One of the smaller nits I noticed when looking at profiles generated by 6.8.1 (using -prof -auto-all) is that class methods show up as cost centers named something like "$f5". I can look at the call stack and figure out that $f5 is probably the call to a particular class method in a particular location, but I was wondering what it might take to make that more user-friendly (I'd want to see the class name, method name and the instance being used in some format, ideally). Is that information readily available and it is just a matter of making -auto-all smarter, or is there a reason this would be tricky? Thanks, - Ravi

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GHC generated dll makes Excel crash on exit.
by Olivier Boudry 04 Dec '07

04 Dec '07

Hi all, I need to call an Haskell module from Excel and as an exercise I started to play with the example given in GHC documentation: http://www.haskell.org/ghc/dist/current/docs/users_guide/win32-dlls.html I could build the DLL without problem but encountered a problem when using it. I created an Excel document using the dll. If I open the Excel document, do something that will trigger a function call in the DLL, then Excel will crash on Exit. On the opposite if I open the same document and changes cells not related to the function the program closes properly. I does not crash directly on the function call but later, just when I close Excel. As it crashes when closing Excel I suspect something is wrong when unloading the dll. I modified the dllMain.c code to handle the DLL_PROCESS_DETACH event but it doesn't solve the problem. } else if (reason == DLL_PROCESS_DETACH) { shutdownHaskell(); return TRUE; } I attached the code to this e-mail. I built the dll this way: ghc -fglasgow-exts -c adder.hs ghc -c dllMain.c ghc -shared -o adder.dll adder.o adder_stub.o dllMain.o Any idea on what could go wrong? Another event to handle? Thanks, Olivier.

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