March 2010 - Libraries

Announce: Haskell Platform 2010.1.0.0 (beta) release
by Don Stewart 31 Mar '10

31 Mar '10

Live from (post-) Zurihac, I'm pleased to announce the 2010.1.0.0 (beta branch) release of the Haskell Platform, supporting GHC 6.12. http://hackage.haskell.org/platform/ The Haskell Platform is a comprehensive, robust development environment for programming in Haskell. For new users the platform makes it trivial to get up and running with a full Haskell development environment. For experienced developers, the platform provides a comprehensive, standard base for commercial and open source Haskell development that maximises interoperability and stability of your code. The 2010.1.0.0 release is a beta release for the GHC 6.12 series of compilers. It currently doesn't provide a Windows installer (which defaults to GHC 6.10.4 for now). We expect to make the stable branch with GHC 6.12.2 in soon. This release includes a binary installer for Mac OS X Snow Leopard, as well as source bundles for an Unix system, and a new design. The Haskell Platform would not have been possible without the hard work of the Cabal development team, the Hackage developers and maintainers, the individual compiler, tool and library authors who contributed to the suite, and the distro maintainers who build and distribute the Haskell Platform. Thanks! -- Don (for The Platform Infrastructure Team)

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Haskell Platform 2010.1.0.0 Windows installer RC2
by Mikhail Glushenkov 31 Mar '10

31 Mar '10

Hi all, I've uploaded the second RC of the Haskell Platform 2010.1.0.0 Windows installer to http://code.haskell.org/~refold/HaskellPlatform-2010.1.0.0-setup.exe Unless someone finds serious bugs in this RC, it can be released unchanged. What's new in 2010-1.0.0-rc2: * $INSTDIR/mingw/bin is now added to PATH (#114) * cabal-install version updated to 0.8.1 * regex-posix now works (thanks to Simon Marlow!) * WinGHCi version updated to 1.0.5 * Profiling versions of all libraries are now included (#87) -- () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments

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Haskell Platform 2010.1.0.0 Windows installer RC3
by Mikhail Glushenkov 30 Mar '10

30 Mar '10

Hi all, I've uploaded the third (and, hopefully, final) RC of the Haskell Platform 2010.1.0.0 Windows installer to http://code.haskell.org/~refold/HaskellPlatform-2010.1.0.0-setup.exe Unless someone finds serious bugs in this RC, it can be released unchanged. What's new in 2010.1.0.0-rc3: * Fixed a PATH issue that prevented alex and happy from working (reported by Krasimir Angelov) * $APPDATA/cabal/bin is now added to PATH (reported by Han Joosten) -- () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments

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Bugs in SampleVar and an API proposal
by Bas van Dijk 30 Mar '10

30 Mar '10

Hello, I was browsing over the code of Control.Concurrent.SampleVar and noticed the same kind of bugs I also discovered yesterday in Data.Unique: * Throwing an asynchronous exception at the right time can make the state of a SampleVar inconsistent which can cause a dead-lock. * Numeric expressions are put in a MVar lazily which can cause a space leak. The attached patch bundle contains a patch that fixes them both. The bundle also contains another patch which changes the API of Control.Concurrent.SampleVar. So this patch has to go through the library submission procedure. I propose making SampleVar an abstract (new)type instead of a type synonym. Advantages: * Users can not "screw up" the internal state like they can do now. * We can define instances for SampleVars without using the TypeSynonymInstances language extension. (This is actually the reason I bumped into the type synonym nature of SampleVars. I'm making a small library that defines some classes and I couldn't make SampleVar instances for them) Disadvantages: * Potentially breaks existing code. However if it breaks your code you are probably touching the internals which you shouldn't do anyway. Discussion period: 1 week (Because I think this is a no-brainer) Note I didn't derive an instance for Typeable for the SampleVar newtype. This should be done, but I don't know the proper way (manually, LANGUAGE DeriveDataTypeable or INSTANCE_TYPEABLE1(SampleVar,sampleVarTc,"SampleVar") ?). regards, Bas

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Re: Haskell Platform 2010.1.0.0 Windows installer RC2
by Han Joosten 30 Mar '10

30 Mar '10

The new version is great! I really appreciate it. Thanks! However, I think that it would be nice if it would update the path to contain the cabal\bin directory, into which cabal will install all executables. Now the user has to do that manually. Is this possible? And is this the right place to do such requests? Han Joosten -- View this message in context: http://old.nabble.com/Haskell-Platform-2010.1.0.0-Windows-installer-RC2-tp2… Sent from the Haskell - Libraries mailing list archive at Nabble.com.

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Fwd: Haskell Platform 2010.1.0.0 Windows installer RC2
by Krasimir Angelov 30 Mar '10

30 Mar '10

I forgot to reply to haskell-platform(a)projects.haskell.org and libraries(a)haskell.org. ---------- Forwarded message ---------- From: Krasimir Angelov <kr.angelov(a)gmail.com> Date: Tue, Mar 30, 2010 at 8:43 AM Subject: Re: Haskell Platform 2010.1.0.0 Windows installer RC2 To: Mikhail Glushenkov <the.dead.shall.rise(a)gmail.com> The installation works fine but after that when I try to use Alex it fails with: alex.exe: C:\Program Files\Haskell Platform\2010.1.0.0\alex-2.3.2/AlexTemplate-ghc: openFile: does not exist (No such file or directory) It is the same for happy: happy.exe: C:\Program Files\Haskell Platform\2010.1.0.0\happy-1.18.4/HappyTemplate-arrays-coerce: openFile: does not exist (No such file or directory) On Sat, Mar 27, 2010 at 10:23 PM, Mikhail Glushenkov <the.dead.shall.rise(a)gmail.com> wrote: > Hi all, > > I've uploaded the second RC of the Haskell Platform 2010.1.0.0 > Windows installer to > > http://code.haskell.org/~refold/HaskellPlatform-2010.1.0.0-setup.exe > > Unless someone finds serious bugs in this RC, it can be released unchanged. > > What's new in 2010-1.0.0-rc2: > > * $INSTDIR/mingw/bin is now added to PATH (#114) > > * cabal-install version updated to 0.8.1 > > * regex-posix now works (thanks to Simon Marlow!) > > * WinGHCi version updated to 1.0.5 > > * Profiling versions of all libraries are now included (#87) > > -- > () ascii ribbon campaign - against html e-mail > /\ www.asciiribbon.org - against proprietary attachments > _______________________________________________ > Libraries mailing list > Libraries(a)haskell.org > http://www.haskell.org/mailman/listinfo/libraries >

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proposed change to transformers package
by Ross Paterson 29 Mar '10

29 Mar '10

I propose to rename some of the modules in the transformers package so that it no longer conflicts with the mtl package: Control.Monad.Identity renamed as Data.Functor.Identity Control.Monad.Trans split between Control.Monad.Trans.Class and Control.IO.Trans.Class Then Control.Monad.Identity and Control.Monad.Trans are added to monads-fd making it closer to mtl. Darcs repositories: http://code.haskell.org/~ross/transformers/ http://code.haskell.org/~ross/monads-fd/ Docs: http://code.haskell.org/~ross/transformers/dist/doc/html/transformers/ http://code.haskell.org/~ross/monads-fd/dist/doc/html/monads-fd/

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Bugfixes for withThread and runInUnboundThread
by Bas van Dijk 29 Mar '10

29 Mar '10

Hello, I discovered two similar bugs in Control.Concurrent: * In the function: 'runInUnboundThread' a thread is forked which first installs an exception handler before performing the given IO computation. However it should first block asynchronous exceptions before forking the thread to ensure that the exception handler is always installed. In the attached patch I use the 'blockedApply' function which also ensures that the forked IO computation has the same blocked state as its parent thread. * There's a similar problem in the internal withThread function (which AFAIKS is only called in threadWaitRead). withThead also forgets to properly block asynchronous exceptions before forking a thread which needs to install an exception handler. In this case I didn't use blockedApply but only used block because withThread is only called with 'waitFd' which only performs an FFI call which can't receive asynchronous exceptions anyway. Should I make a bugreport or can this be applied immediately? regards, Bas

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Compiling regex-posix on Windows
by Mikhail Glushenkov 29 Mar '10

29 Mar '10

Hi all, The only problem stalling the release of the Windows installer for the new Haskell Platform is the bug in regex-posix. It compiles fine (using the libregex.a library from MinGW), but fails at runtime with the following error: Prelude> import Text.Regex.Posix Prelude Text.Regex.Posix> "bar" =~ "(foo|bar)" ::Bool Loading package array-0.3.0.0 ... linking ... done. Loading package bytestring-0.9.1.5 ... linking ... done. Loading package containers-0.3.0.0 ... linking ... done. Loading package mtl-1.1.0.2 ... linking ... done. Loading package regex-base-0.93.1 ... linking ... done. Loading package regex-posix-0.94.1 ... linking ... <interactive>: E:\Program Fil es (x86)\Haskell\regex-posix-0.94.1\ghc-6.12.1\HSregex-posix-0.94.1.o: unknown s ymbol `_regerror' : unable to load package `regex-posix-0.94.1' Prelude Text.Regex.Posix> Unfortunately, Chris, the maintainer, doesn't have access to a Windows machine with GHC currently, and therefore can't help me. I'd appreciate any pointers on how to fix this. -- () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments

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Asynchronous exceptions and laziness bugs in Control.Concurrent.QSem/QSemN
by Bas van Dijk 29 Mar '10

29 Mar '10

Hello, after discovering the bugs regarding asynchronous exceptions and laziness in Data.Unique and Control.Concurrent.SampleVar I became a bit suspicious about the other concurrency mechanisms. It looks like Control.Concurrent.Chan is safe because it uses modifyMVar_ internally which performs the necessary block. Control.Concurrent.QSem and QSemN are not alright however! They both suffer the same bugs: * Potential dead-lock due to not blocking asynchronous exceptions. * Potential space-leak because of lazily putting numeric expression in a MVar. The attached patch fixes these bugs. regards, Bas

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