November 2008 - Haskell-Cafe

Re: [Haskell-cafe] varargs zip
by Jason Dusek 21 Nov '08

21 Nov '08

Sean Leather <sean.leather(a)gmail.com> wrote: > > example = zip [1,2::Int] ['a','b'] ["1","b"] :: > > [(Int,Char,String)] > > BTW, I realized that this example also works in yours. You > weren't giving enough type annotations. Yes, exactly. Or in other words, the class definition does not correctly specify the dependencies. That is what I am writing in about -- I don't want clients to 'zip' to be required to put all those type annotations in. -- _jsn

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Begginer question about alignment in Storable
by Maurício 21 Nov '08

21 Nov '08

Hi, I need to make the following structure into an instance of Storable: struct { double w[2]; } Can I assume that its function 'alignment' should return the same as "alignment (1::CDouble)"? Or should it be "2 * alignment (1::CDouble)"? (I've read the wikipedia article about memory alignment, and what I understand is that there's a better alignment for hardware efficiency but compilers and programmers can do almost anything about it. What can I do when writing a library wrapper if I don't know what kind of compiler pragmas were used in all platforms that library was compiled?) Thanks, Maurício

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System Fc in GHC
by Hugo Pacheco 21 Nov '08

21 Nov '08

Since System Fc is implemented in the latest releases of GHC, is it implemented in Haskell so that I can play with the translator? Can I find it in the ghc sources? Thanks, hugo -- www.di.uminho.pt/~hpacheco

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portable arrow instances
by Wolfgang Jeltsch 21 Nov '08

21 Nov '08

Hello, how do I make a library work with both GHC 6.8 and GHC 6.10? According to <http://www.haskell.org/haskellwiki/Upgrading_packages#Arrow_instances>, I should change all my Arrow instances but then they don’t work with GHC 6.8 anymore, do they? Or is the solution to force GHC 6.8 users to use base-4.0.0.0? Best wishes, Wolfgang

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Hackage policy question
by Iavor Diatchki 20 Nov '08

20 Nov '08

Hi, I just noticed that hackage has introduced a new policy to disallow changes to a package without bumping the version. I understand that this is probably a good idea for changes to the source code, but it really would be nice to have a backdoor that allows for other changes. For example, I just uploaded a package, and realized that I forgot to add a home-page entry in the cabal file. I do not plan to increase the version number of my application, only so that I can upload a new version (the source code has not changed after all!). I can imagine similar problems related to fixing typos in the description, and other fixes to the meta-data. So, could we please revert to the old policy? (if we really want to be fancy, the hackage upload script could check that the source code, and other fields, such as LICENSE have not changed, as these should really bump the version... in the mean time though, I think just being responsible members of the community would work just as well!). -Iavor

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Problem with GTK on OS X -- installed from source
by Jeff Heard 20 Nov '08

20 Nov '08

Building my app with gtk2hs, I get the following error when I try to compile a file that uses Template Haskell (I'm not using TH to do anythign with GTK, but it loads the package anyway) Loading package gtk-0.9.13 ... <command line>: can't load .so/.DLL for: gthread-2.0 (dlopen(libgthread-2.0.dylib, 10): image not found)

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Haskell Reddit
by Don Stewart 20 Nov '08

20 Nov '08

I'm not sure if the cafe@ knows this, but there's a bit of a Haskell community (1200+ subscribers) built up around the Haskell subreddit on reddit.com, http://www.reddit.com/r/haskell/ A good source for news other than what appears on Planet Haskell. -- Don P.S. Feel free to submit things you like, so I don't have to :-)

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Re: [Haskell] ANNOUNCE: Haddock version 2.4.0
by David Waern 20 Nov '08

20 Nov '08

2008/11/6 Wolfgang Jeltsch <g9ks157k(a)acme.softbase.org>: > Am Donnerstag, 6. November 2008 00:21 schrieb David Waern: >> * Add framed view of the HTML documentation > > After many years with many people telling us that frames are bad, you add > frame support to Haddock? Hmm. You should discuss this with Simon Marlow, as it was his idea. Thomas Schilling implemented it. Personally, I think the frames are quite handy, although not that pretty in their current form. More importantly, you don't need to use them if you don't want to. Haddock still generates the normal index.html as well as frames.html. David

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GHC 6.10.1 and cabal[-install]
by Wolfgang Jeltsch 20 Nov '08

20 Nov '08

Hello, I installed GHC 6.10.1 today and expected it to contain the cabal command line utility. Unfortunately, this was not the case. Where can I download it? How do I install and configure it so that it is integrated best with GHC 6.10.1? For example, should cabal use some directory in the GHC tree to place compiled packages in? <http://hackage.haskell.org/> still links to cabal-install for a convenient way for installing packages. I thought that cabal-install is outdated. Isn’t it? Generally, Cabal info and documentation ist too hard to find on the web, in my opinion. Best wishes, Wolfgang

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(OT) Has GHC stopped being the "Glorious" Glasgow Haskell Compiler?
by Benjamin L.Russell 20 Nov '08

20 Nov '08

IIRC, until very recently, the home page for GHC (see http://www.haskell.org/ghc/index.html) listed the compiler name as "The Glorious Glasgow Haskell Compiler." I wanted to write a blog entry using this aspect, but now the adjective "Glorious" seems to be missing. Am I missing something, or has the nickname been changed? -- Benjamin L. Russell http://dekudekuplex.wordpress.com/

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