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Re: [Haskell-cafe] Papers from the 2005 Haskell Workshop (Tallinn)?
by Dimitry Golubovsky 06 Oct '05

06 Oct '05

Nils Anders Danielsson wrote: > > Most authors do put their papers on their web pages nowadays. > In particular, I would like to read the paper on "halfs" (haskell filesystem). Googling for <halfs haskell filesystem> gave nothing but the Workshop's schedule and ACM Library TOC. Dimitry Golubovsky Middletown, CT

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Define a data structure of a predicate
by Sara Kenedy 06 Oct '05

06 Oct '05

Hello you all, I am a newbie in Haskell. Now I am working on datatype structure of Haskell, especially on predicate. Today I try to search on Internet to find the reference document but I did not find the specific. If any of you know how to define a data structure for the abstract syntax of predicate logicI , for example : x^2 + 3*x + 2 > 0, if you don't mind, please share with me. Thanks in advance.

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CFP: PAPP 2006
by Ch. A. Herrmann 06 Oct '05

06 Oct '05

--------------------------------------------------------------------- Please accept our apologies if you have received multiple copies. Please feel free to distribute it to those who might be interested. --------------------------------------------------------------------- ---------------------------------------------------------- CALL FOR PAPERS PAPP 2006 Third International Workshop on Practical Aspects of High-level Parallel Programming http://graal.ens-lyon.fr/~abenoit/conf/papp2006.html part of ICCS 2006 The International Conference on Computational Science May 28-31, 2006, University of Reading, UK ---------------------------------------------------------- AIMS AND SCOPE Computational Science applications are more and more complex to develop and require more and more computing power. Parallel and grid computing are solutions to the increasing need for computing power. High level languages offer a high degree of abstraction which ease the development of complex systems. Moreover, being based on formal semantics, it is possible to certify the correctness of critical parts of the applications. Algorithmic skeletons, parallel extensions of functional languages such as Haskell and ML, parallel logic and constraint programming, parallel execution of declarative programs such as SQL queries, etc. have produced methods and tools that improve the price/performance ratio of parallel software, and broaden the range of target applications. The PAPP workshop focuses on practical aspects of high-level parallel programming: design, implementation and optimization of high-level programming languages and tools (performance predictors working on high-level parallel/grid source code, visualisations of abstract behaviour, automatic hotspot detectors, high-level GRID resource managers, compilers, automatic generators, etc.), applications in all fields of computational science, benchmarks and experiments. Research on high-level grid programming is particularly relevant. The PAPP workshop is aimed both at researchers involved in the development of high level approaches for parallel and grid computing and computational science researchers who are potential users of these languages and tools. TOPICS We welcome submission of original, unpublished papers in English on topics including: * high-level models (CGM, BSP, MPM, LogP, etc.) and tools for parallel and grid computing * high-level parallel language design, implementation and optimisation * functional, logic, constraint programming for parallel, distributed and grid computing systems * algorithmic skeletons, patterns and high-level parallel libraries * generative (e.g. template-based) programming with algorithmic skeletons, patterns and high-level parallel libraries * applications in all fields of high-performance computing (using high-level tools) * benchmarks and experiments using such languages and tools PAPER SUBMISSION AND PUBLICATION Prospective authors are invited to submit full papers in English presenting original research. Submitted papers must be unpublished and not submitted for publication elsewhere. Papers will go through a rigorous reviewing process. Each paper will be reviewed by at least three referees. The accepted papers will be published in the Springer-Verlag Lecture Notes in Computer Science (LNCS) series, as part of the ICCS proceedings. Submission must be done through the ICCS website: http://www.iccs-meeting.org/iccs2006/papers/upload.php We invite you to submit a full paper of 8 pages formatted according to the rules of LNCS, describing new and original results, no later than December 2, 2005. Submission implies the willingness of at least one of the authors to register and present the paper. An early email to Anne.Benoit at ens-lyon.fr with your intention to submit a paper would be greatly appreciated (especially if you have doubts about the relevance of your paper). Accepted papers should be presented at the workshop and extended and revised versions will be published in a special issue of Parallel and Distributed Computing Practices, provided revisions suggested by the referees are made. IMPORTANT DATES December 2, 2005 Full paper due January 31, 2006 Referee reports and notification February 10, 2006 Camera-ready paper due May 2006 Journal version due June 2006 Referee reports July-October 2006 Revision of papers, final notification November 2006 Final paper due PROGRAM COMMITTEE Marco Aldinucci (CNR/Univ. of Pisa, Italy) Olav Beckmann (Imperial College London, UK) Anne Benoit (ENS Lyon, France) Alexandros Gerbessiotis (NJIT, USA) Stephen Gilmore (Univ. of Edinburgh, UK) Clemens Grelck (Univ. of Luebeck, Germany) Christoph Herrmann (Univ. of Passau, Germany) Zhenjiang Hu (Univ. of Tokyo, Japan) Frédéric Loulergue (Univ. Orléans, France) Casiano Rodriguez Leon (Univ. La Laguna, Spain) Alexander Tiskin (Univ. of Warwick, UK) ORGANIZERS Dr. Anne BENOIT Laboratoire d'Informatique du Parallélisme Ecole Normale Supérieure de Lyon 46 Allée d'Italie 69364 Lyon Cedex 07 - France Pr. Frédéric LOULERGUE Laboratoire d'Informatique Fondamentale d'Orléans Université d'Orléans Bâtiment IIIA - Rue Léonard de Vinci - BP6759 45067 Orléans Cedex 2 - France

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RE: [Haskell-cafe] Problem with sparc distribution?
by Simon Marlow 05 Oct '05

05 Oct '05

On 29 September 2005 10:37, Christian Maeder wrote: > I've repacked the distribution and put it at: > http://www.informatik.uni-bremen.de/agbkb/forschung/formal_methods/CoFI/ hets/solaris/ghc-6.4.1-sparc-sun-solaris2.tar.bz2 > > Can you copy it to http://www.haskell.org/ghc/dist/6.4.1/, Simon? Done. Simon

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Converting [Word8] to String
by Joel Reymont 05 Oct '05

05 Oct '05

Folks, How do I convert a list of bytes to a string? Cale has suggested a neat way of parsing binary packets in this thread: http://www.mail-archive.com/haskell-cafe@haskell.org/msg09413.html and I'm trying to create a packet reader for a Pascal-style string where the length is the first byte and the list of characters follows. I understand that I can take the first X bytes of the byte list but how do I make this into a string? I'll probably use fast packed strings to read from the socket handle and will unpack the fps into a list of bytes for parsing. Thanks, Joel -- http://wagerlabs.com/

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IRC for spreading information
by John Goerzen 04 Oct '05

04 Oct '05

I've got a bit of a concern to raise regarding reliance on IRC for spreading information important to the community. As I was preparing this week's HWN, I made the comment on #haskell that it's been a quiet week. Several people that were at ICFP and the workshops disagreed, saying there had been a lot of activity. But none of it appeared on the Haskell lists. With the help of some IRCers, I found information in Autrijus' blog and a link to some IRC logs. There *was* a lot going on. I would like to make a friendly request that important things like this be posted to the mailing lists. I don't have a problem with them being on IRC as well, but there are several problems with it being "IRC only" or "IRC mostly" or even "conference only": * The only way to participate effectively is to be in the IRC room at the exact same time as the other participants. Very difficult to include everyone in a global community such as that. * It is very cumbersome, and sometimes even impossible, to extract conversations from IRC logs, given that several conversations could have been happening at once in the channel. Mailing list archives, with support for threads, are much easier to read. As an aside, I will not be writing up summaries of IRC logs for HWN, though if someone else cares to do so and send them to me, I'd put them in. I simply don't have the time or the desire for a pounding headache that most people get from reading IRC logs ;-) -- John

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Short Cut / Rewrite Rules Problem in GHC
by Chris 04 Oct '05

04 Oct '05

Hi All. I am a student and a noob to Haskell. I am having some trouble with an example from the paper "Playing by the rules: Rewriting as a practical optimisation technique in GHC" by Simon Peyton Jones, Andrew Tolmach and Tony Hoare, specifically, the Short- cut Deforestation example in section 3.1. I was trying to compile the following using GHC version 6.4 on Mac OS X 10.4. The definition for build and the rule are from the paper (the rule also appears in the GHC online doc in section 7.10.1). ----------------------------------------------------- -- BOF -- File: Main.hs module Main where build :: (forall b. (a->b->b) -> b -> b) -> [a] build' g = g (:) [] {-# RULES "foldr/build" forall k z (g::forall b. (a->b->b) -> b -> b) . foldr k z (build g) = g k z #-} main :: IO () main = do putStr "" -- EOF ----------------------------------------------------- When I enable the extensions for GHC I get the following error: chris$ ghc -fglasgow-exts --make Main.hs Chasing modules from: Main.hs Compiling Main ( Main.hs, Main.o ) Main.hs:15:1: lexical error When I don't have them enabled it gives this error: chris$ ghc --make Main.hs Chasing modules from: Main.hs Compiling Main ( Main.hs, Main.o ) Main.hs:8:18: parse error on input `.' I have also tried moving the RULES option to the top of of the file above "module Main", but I still get the same errors. Also, should the definition of build be: build :: forall a. (forall b. (a -> b -> b) -> b -> b) -> [a] build g = g (:) [] If I try to load the Main.hs file in HUGS with the -98 option and the above version of build (with the forall a.), it works without a problem. However, it still gives the same errors in GHC. Additionally, I tried this on a different version of GHC, 6.2.2 on a x86 box running Gentoo Linux, and it yielded the same results. I am completely lost and would greatly appreciate any help. Thanks so much. - Chris.

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Re: [Haskell-cafe] Endian conversion
by Marc Ziegert 03 Oct '05

03 Oct '05

nice project. (except that winonly-closedsource-....thing. my condolence.) on which platform are you programming? mac? linux-ppc? i see that you understood most of that code. big-endian-test: the number 1234 has two ends (like a sausage), the end with the 1 is the big end (1000), the 4 is the little one. if you save he number 1 as int in little endian, then you write the bytes 01 00 00 00, and in big endian it is 00 00 00 01. so, if you read the first char, then it will either be ==1 (little) or /=1 (big). to write that LittleEndian stuff, you only need to replace Big with Little and "if be then" with "if not be then". it is the question wether to use he function xyz0(derived) or xyzR(reverse order of bytes). i hope, that the compiler optimizes "if True" away. to use the Storables, read the docu about the libs(functions) Network.Socket(sendBufTo) Foreign.Marshal.Utils(with) Foreign.Storable(peekThis,peekThat) you just need to read "LittleEndian CInt", remove that "LittleEndian"-constructor, work with that CInt, put the "BigEndian"-constructor at that CInt, write it... maybe you need to convert LE and BE enums, too. use "(toEnum . fromEnum)" to convert between any enum and CInt. good n8. - marc Joel Reymont wrote: > Well, I liked that bit of Template Haskell code that Marc sent. I'm > now stuck trying to adapt it to read Storables :-). > > It seems, on a second glance, that there's not that much to adapt. If > I read Marc's code correctly it "derives" Storable and uses the peek, > etc. methods to swap bytes around. Which means to me that so long as > the byte swapping methods are implemented and I try to store a > BigEndian or LittleEndian it would be stored correctly for me. > > Is this so? > > To recap, I'm trying to read binary packets from a socket and the > first thing I do is read the packet length. I then need to read the > packet body where the numbers are little or big endian. After > processing the packet I need to write it out and the numbers again > could be little or big endian. > > I could read a FastString from a socket since it has IO methods but I > don't know how to convert the FS into a pointer suitable for > Storable. So much to learn :-). > > Thanks, Joel > > On Oct 3, 2005, at 9:33 PM, Udo Stenzel wrote: > > > Why don't you pull out 4 bytes and assemble them manually? Three > > shifts, logical ors and fromIntegrals aren't that much of a burden > > after > > all. > > -- > http://wagerlabs.com/idealab > > > > > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe(a)haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe >

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14-queens Problem
by Yousry Abdallah 03 Oct '05

03 Oct '05

hi, is it fast to calculate all solutions for the 14-queens problem in 7 minutes? (searchspace size is 7,68E+031)

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NewBinary code for working with FastStrings
by Joel Reymont 02 Oct '05

02 Oct '05

Does anyone know why the FastString code in Binary.hs is commented out? -- http://wagerlabs.com/

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