gmane.comp.lang.haskell.cafe

Re: Model-driven development (was: Haskellparticipting in big science like CERN Hadrian...)

Martin DeMello — 2008-10-07T06:37:20

2008/10/4 Jason Dagit codersbase.com>: An option is to generate python via an edsl, and use the object oriented trick of overriding the generated code in a separate file. I've done that fairly successfully when generating java from a ruby edsl and some templates, for example. martin

Re: newbie questions (read, etc.,with Data.ByteString.Lazy.Char8)

wman — 2008-10-07T06:34:05

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Re: I'll do USB in Haskell - tips?

Krzysztof Skrzętnicki — 2008-10-07T04:52:44

Have a look at libusb version 1.0 API. It looks pretty promising: http://libusb.wiki.sourceforge.net/Libusb1.0 All best Christopher Skrzętnicki _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe< at >haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: newbie questions (read, etc.,with Data.ByteString.Lazy.Char8)

Don Stewart — 2008-10-07T04:50:35

666wman: Oh, that's interesting. Did they actually recompile? (you used -fforce-recomp). Otherwise, might be an idea to use hpaste.org to paste teh Main1,2,3 source code, since I think people reading don't know what is represented in each program at this point.

Re: newbie questions (read, etc.,with Data.ByteString.Lazy.Char8)

wman — 2008-10-07T04:44:48

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Re: newbie questions (read, etc.,with Data.ByteString.Lazy.Char8)

Don Stewart — 2008-10-07T04:27:52

666wman: Note that without -O or -O2 no strictness analysis is performed. So that tail recursive loop ... won't be. You could try -Onot -fstrictness just for kicks, to see why strictness analysis is important when writing in a tail recursive style.

Re: newbie questions (read, etc.,with Data.ByteString.Lazy.Char8)

Mike Coleman — 2008-10-07T04:17:01

That did the trick--thanks. For input large enough to be a good test, this is I/O-bound on my laptop (the speed of the compiled and interpreted versions are almost identical), so I'll have to try it on a bigger machine tomorrow. Mike

Re: Name for Haskell based VPN Client/Server

John Van Enk — 2008-10-07T04:02:48

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Re: newbie questions (read, etc.,with Data.ByteString.Lazy.Char8)

Brandon S. Allbery KF8NH — 2008-10-07T03:59:06

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Re: newbie questions (read, etc.,with Data.ByteString.Lazy.Char8)

wman — 2008-10-07T03:54:44

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Re: newbie questions (read, etc.,with Data.ByteString.Lazy.Char8)

wman — 2008-10-07T03:36:22

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Re: After upgrade bytestring to 0.9.1.3,my program cannot run.

Don Stewart — 2008-10-07T03:21:27

magicloud.magiclouds: This likely means your program is using some package A, that has been compiled against (and loading) old bytestring, but also loading the new bytestring. The solution is to recompile whatever your library 'A' is that is trying to use the old bytestring. Or try compiling it , with ghc --make

Re: newbie questions (read, etc.,with Data.ByteString.Lazy.Char8)

Don Stewart — 2008-10-07T03:19:58

tutufan: Oh wow, runghc is an interpreter. It is on average about 30x slower than compiled code. To compile, try something like: ghc -O2 --make A.hs And enjoy the native codes. :)

Re: newbie questions (read, etc.,with Data.ByteString.Lazy.Char8)

Don Stewart — 2008-10-07T03:19:15

Hmm. How are you compiling it? Using bytestring 0.9.1.x ? Should be fast, http://shootout.alioth.debian.org/gp4/benchmark.php?test=sumcol&lang=all Assuming you're turning on optimisations ( ghc -O2 )

Re: newbie questions (read, etc.,with Data.ByteString.Lazy.Char8)

wman — 2008-10-07T03:17:45

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After upgrade bytestring to 0.9.1.3,my program cannot run.

Magicloud — 2008-10-07T03:16:54

Just a simple text process program. When I runhaskell it. I got: GHCi runtime linker: fatal error: I found a duplicate definition for symbol fps_minimum whilst processing object file ~/.cabal/lib/bytestring-0.9.1.3/ghc-6.8.3/HSbytestring-0.9.1.3.o This could be caused by: * Loading two different object files which export the same symbol * Specifying the same object file twice on the GHCi command line * An incorrect `package.conf' entry, causing some object to be loaded twice. GHCi cannot safely continue in this situation. Exiting now. Sorry.

Re: newbie questions (read, etc.,with Data.ByteString.Lazy.Char8)

Mike Coleman — 2008-10-07T03:14:00

Thanks for your replies. Hoogle is pretty cool--I didn't know about that. I ended up with this, which is pretty close to the original (it will also bomb if given non-integer input): import qualified Data.ByteString.Lazy.Char8 as L import qualified Data.Maybe as M main = do contents <- L.getContents print (sumFile contents) where sumFile = sum . map (fst . M.fromJust . L.readInt) . L.words One further problem I've encountered: My Haskell program runs under 'runghc', but I get a link error when compiling it (GHC 6.8.2, latest Ubuntu). Any suggestions? $ ghc -o LazySumFile LazySumFile.hs LazySumFile.o: In function `sOz_info': (.text+0x200): undefined reference to `bytestringzm0zi9zi0zi1_DataziByteStringziLazzyziChar8_readInt_closure' LazySumFile.o: In function `sOF_info': (.text+0x35d): undefined reference to `bytestringzm0zi9zi0zi1_DataziByteStringziLazzyziChar8_words_closure' LazySumFile.o: In function `sRF_info': (.text+0x4d7): undefined reference to `bytestringzm0zi9zi

Re: newbie questions (read, etc.,with Data.ByteString.Lazy.Char8)

Don Stewart — 2008-10-07T03:12:23

666wman: Never unpack a bytestring. import qualified Data.ByteString.Lazy.Char8 as S main = print . go 0 =<< S.getContents where go n s = case S.readInt s of Nothing -> n Just (k,t) -> go (n+k) (S.tail t) Assuming you're reading int, integers or doubles.

Re: newbie questions (read, etc.,with Data.ByteString.Lazy.Char8)

wman — 2008-10-07T03:07:58

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Re: Name for Haskell based VPN Client/Server

Gwern Branwen — 2008-10-07T02:22:21

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Re: newbie questions (read, etc.,with Data.ByteString.Lazy.Char8)

Daniel Fischer — 2008-10-07T02:35:15

Am Dienstag, 7. Oktober 2008 04:21 schrieb Jason Dagit: Since readInt returns a Maybe (Int,ByteString), Data.List.unfoldr would be a better fit for his needs. The bytestring-lexing package (http://hackage.haskell.org/packages/archive/bytestring-lexing/0.1.2/doc/html/Data-ByteString-Lex-Double.html) provides readDouble, which is also pretty fast, I think. At least parsec 3.0.0 has ByteString parsing modules (I've never used it, so I don't know how well they work). IIRC, there's a plan to expand the bytestring-lexing package, too. More's underway, readDouble already delivered. partially.