- Haskell-Cafe - Haskell.org

pleac, examples, etc
by brad clawsie 15 Nov '06

15 Nov '06

it would be great if some of the more informed posters here took a stab at filling in http://pleac.sourceforge.net/pleac_haskell/index.html a neat site for cookbook-style problem solving from looking over haskell documentation for a few months now, i would say what is missing is one central cookbook-style document (want to query a database? want to parse xml? etc etc) thanks

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Great language shootout: reloaded
by dons＠cse.unsw.edu.au 14 Nov '06

14 Nov '06

So back in January we had lots of fun tuning up Haskell code for the Great Language Shootout[1]. We did quite well at the time, at one point ranking overall first[2]. After doing all we could with ghc 6.4.2, the Haskell entries have been left for the last 10 months, while we worked on new libraries (bytestring, regex-*). 1. http://shootout.alioth.debian.org/ 2. http://www.cse.unsw.edu.au/~dons/data/haskell_1.html Now the time has come to reload the shootout for another round! GHC 6.6 is on the 'sandbox' debian machine, and will soon be on the other shootout boxes[3], which means we can use: * Data.ByteString * regex-* libraries 3. http://shootout.alioth.debian.org/sandbox/benchmark.php?test=all&lang=ghc&l… And thus greatly improve: fannkuch fasta k-nucleotide regex-dna reverse-complement sum-file While we're here we should fix: chameneos And anything else you want to take a look at. A community page has been set up to which you can submit improved entries: http://www.haskell.org/haskellwiki/Great_language_shootout So, install GHC 6.6, read up on Data.ByteString and the new regex libs, and submit faster code to the wiki! Our shootout-interface officer, musasabi, can then commit them to shootout cvs, once consensus is reached on the best code to submit. Let's take back first place! :) -- Don

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deepSeq vs rnf
by Chad Scherrer 14 Nov '06

14 Nov '06

Hi, I had posted this question a while back, but I think it was in the middle of another discussion, and I never did get a reply. Do we really need both Control.Parallel.Strategies.rnf and deepSeq? Should we not always have x `deepSeq` y == rnf x `seq` y ? Maybe there's a distinction I'm missing, but it seems to me they're basically the same. -- Chad Scherrer "Time flies like an arrow; fruit flies like a banana" -- Groucho Marx

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best Linux for GHC?
by Bulat Ziganshin 14 Nov '06

14 Nov '06

Hello haskell-cafe, Now i'm consider installation of some Linux version at my box. My friend offered me 3 variants: SuSe, Fedora Core 5, free variant of RedHat (i can't remember its name, may be Ubuntu?) what may be best for GHC-based development? in particular, i want to compile Haskell itself i suspect that it is a really dumb question, and GHC will work great just with any linux i can find :) -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com

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Testing non-exported functions using ghci
by John Ky 13 Nov '06

13 Nov '06

Hello, I have modules that don't export some functions. Is there a way I can access them from ghci without exporting them? Thanks -John

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Re: [Haskell-cafe] Re: best Linux for GHC?
by Luis F. Araujo 13 Nov '06

13 Nov '06

Alex Queiroz wrote: >> Hallo, >> >> On 11/13/06, Mark T.B. Carroll <Mark.Carroll(a)aetion.com> wrote: >> >>> How up to date will Debian unstable's GHC be kept, though? It seems >>> pretty good at the moment, but there have been times when we've had to >>> install from source instead of via Debian earlier this year so that we >>> had GHC features and bugfixes in place - the Debian version has got >>> rather out of date at times with respect to stuff we needed. >>> >>> >> No OpenGL neither Gtk2hs in Debian Sid yet. :-( >> I'd recommend Gentoo for using these kind of packages. We even have darcs repository versions of Gtk2Hs in our gentoo haskell overlay. Regards,

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Section Syntax Errors
by Aditya Siram 13 Nov '06

13 Nov '06

Hi all, I am learning about sections and currying from SOE. There are three functions below. The first is from SOE and the other two are my own practice functions. Why does the third function fail? --Test for negative numbers (from SOE pg 109). This works posInts :: [Integer] -> [Bool] posInts = map (> 0) --Add 1 to a list of numbers. This works. addOne :: [Integer] -> [Integer] addOne = map (+ 1) --Subtract 1 from a list of numbers. This does NOT work. --Fails in Hugs with: -- Instance of Num (Integer -> Integer) required for definition of testSections -- I tried : subOne :: Num a => [a] -> [a] -- and : subOne :: [Float] -> [Float] --in case the problem is with negative numbers. They both fail. --Without any type signature I get: -- Unresolved top level overloading subOne :: [Integer] -> [Integer] subOne = map (- 1) Thanks... Deech _________________________________________________________________ Add a Yahoo! contact to Windows Live Messenger for a chance to win a free trip! http://www.imagine-windowslive.com/minisites/yahoo/default.aspx?locale=en-u…

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Great language shootout: reloaded
by tpledger＠ihug.co.nz 13 Nov '06

13 Nov '06

Donald Bruce Stewart wrote: [...] > While we're here we should fix: > chameneos > And anything else you want to take a > look at. > > A community page has been set up to > which you can submit improved entries: > http://www.haskell.org/haskellwiki/Great_language_shootout [...] Well, then! I've put a new chameneos solution up on the wiki, and will wait the recommended couple of days for Community Feedback. - Tom

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ByteString FFI
by Donn Cave 13 Nov '06

13 Nov '06

How do people like to set up their foreign I/O functions to return ByteStrings? I was a little stumped over this yesterday evening, while trying to write ` recv :: Socket -> Int -> Int -> ByteString ' Doc says `Byte vectors are encoded as strict Word8 arrays of bytes, held in a ForeignPtr, and can be passed between C and Haskell with little effort.' Which sounds perfect - I'm always up for `little effort'! CString doesn't seem like the right thing for socket results, because the data shouldn't be NUL-terminated, and I might want to realloc when the returned data doesn't fill the buffer. I don't see any other Ptr-related function or constructor in the documentation - am I missing something there? Thanks, Donn Cave, donn(a)drizzle.com

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GHCi 6.6 tab-completion of source file paths not working.
by Daniel McAllansmith 13 Nov '06

13 Nov '06

Hi. I've just installed GHC 6.6 on an amd64 running a gentoo linux distribution. With GHCi from 6.4.2 I could run "ghci" then do Prelude> :l Foo/Bar.hs by hitting tab after Foo to complete the path to Bar.hs This no longer works, hitting tab only shows what's in the pwd. If I run "ghci Foo/Bar.hs" then I can :r fine and I can do a :l Foo.Bar using tab-completion to complete the module name. Tab completion of in-scope functions looks to be working fine. Has anybody else experienced this problem? Thanks Daniel

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