December 2007 - Glasgow-haskell-users

Re: HUnit 1.2.0.0 on 6.8.1 vs 1.1.1 on 6.6.1
by Greg Fitzgerald 11 Dec '07

11 Dec '07

> >> > "abc" @=? "efg" > >> Loading package HUnit-1.2.0.0 ... linking ... done. > >> *** Exception: (unknown) > > On Dec 3, 2007 7:23 AM, Ian Lynagh <igloo(a)earth.li> wrote: > > This is caused by a change in the HUnit library, from > > assertFailure msg = ioError (userError (hunitPrefix ++ msg)) > > to > > assertFailure msg = E.throwDyn (HUnitFailure msg) I've had no luck contacting Dean Herington using the email address posted on the HUnit page. > They just use the latest version in the darcs repositories at the time that they are built Sounds like this is the first case where the latest version isn't a stable one (Go Haskell!). Is it much trouble for package maintainers to package GHC with HUnit.1.1.1? To keep it simple, maybe there should be an HUnitStable branch where 1.1.1 is the latest version? Thanks, Greg

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GHC 6.8.2, Haddock not finding std libs
by Greg Fitzgerald 10 Dec '07

10 Dec '07

> Please test as much as possible One difference between 6.8.1 and 6.8.2 that I see is in running "runhaskell Setup.hs haddock" with Haddock 0.8 on Windows XP. Haddock is no longer able to resolve the names from the standard libraries. Running Haddock for Xyz-0.1... Warning: Xyz: the following names could not be resolved: FilePath Show Eq String Maybe Bool Char Int Thanks, Greg

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Re: type equality symbol
by Johannes Waldmann 10 Dec '07

10 Dec '07

On Fri, 7 Dec 2007, Manuel M T Chakravarty wrote: > The problem is that Haskell 98 already messed that up. > If type functions are to use lower-case letters, [...] Yes. The broken thing is that the upper/lower case distinction has syntactic importance in the language definition at all. I guess this was introduced to avoid writing out some declarations. This is a bad design goal, especially so for a declarative language. Reminds me of ancient Fortran using the first letter of an identifier for implicit typing (I .. N for integer, others for real). Best regards, -- -- Johannes Waldmann -- Tel/Fax (0341) 3076 6479/80 -- ---- http://www.imn.htwk-leipzig.de/~waldmann/ -------

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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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