October 2005 - Haskell

Haskell Weekly News: October 11, 2005
by John Goerzen 11 Oct '05

11 Oct '05

Haskell Weekly News: October 11, 2005 Greetings, and thanks for reading the 11th issue of HWN, a weekly newsletter for the Haskell community. Each Tuesday, new editions will be posted (as text) to [1]the Haskell mailing list and (as HTML) to [2]The Haskell Sequence. 1. http://www.haskell.org/mailman/listinfo/haskell 2. http://sequence.complete.org/ New Releases * PAM 1.0. Henning Guenther [3]announced version 1.0 of his bindings to the PAM authentication libary. 3. http://article.gmane.org/gmane.comp.lang.haskell.general/12250 * cpphs 1.0. Malcolm Wallace [4]announced the release of cpphs version 1.0. 4. http://article.gmane.org/gmane.comp.lang.haskell.general/12233 * MissingH 0.12.0. John Goerzen [5]announced MissingH 0.12.0, which added various enhancements to its binary I/O utilities. 5. http://article.gmane.org/gmane.comp.lang.haskell.general/12257 Calls for Participation * Haskell Communities & Activities Report. Andres Loeh [6]posted a call for contributions to the periodic report. Anyone that's part of a Haskell team, has published Haskell code, written Haskell-related papers or books, etc. is encouraged to submit a short entry about their activities. 6. http://article.gmane.org/gmane.comp.lang.haskell.general/12261 Discussion Papers from the 2005 Haskell Workship. Dimitry Golubovsky [7]noted that papers from the workshop on the ACM site required a login to read. Simon Marlow posted a free link to the papers he co-authored. 7. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/8580 IRC for spreading information. John Goerzen [8]wrote about some concerns regarding using IRC for spreading information to the Haskell community, such as happened recently. It received some discussion on #haskell. 8. http://article.gmane.org/gmane.comp.lang.haskell.cafe/8573 Reducing memory usage. Young Hyun began an interesting [9]thread about tracking down mysterious cases of high RAM usage. Several people made suggestions for things to try, including things that would be useful to others. 9. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/8637 Memoization. Gerd M [10]wondered why Data.Map was slower than he expected in his program. 10. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/8610 Monad Syntax. Tom Hawkins [11]asked about the syntax "| m -> s" in class declarations. Several people explained that this has to do with functional dependencies, an extension to Haskell 98. 11. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/8601 Alternatives to hs-plugins. John Goerzen [12]posted a scenario in which hs-plugins would be useful, but where concerns about its portability may render it inappropriate. Nils Anders Danielsson replied with a link to his code that can call Hugs to dynamically evaluate Haskell snippets. 12. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/8592 Haskell Toolchain Converting fptools to Darcs. Simon Marlow [13]wrote about his ideas for converting fptools from CVS to Darcs. Several people made suggestions and asked questions. 13. http://news.gmane.org/gmane.comp.version-control.darcs.user About Haskell Weekly News Want to continue reading HWN? Please help us create new editions of this newsletter. Please see the [14]contributing information, or send stories to hwn -at- complete -dot- org. There is also a Darcs repository available. 14. http://sequence.complete.org/hwn-contrib

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FMCO 2005: second call for participation
by M.M. Bonsangue 11 Oct '05

11 Oct '05

Our apologies if you receive multiple copies of this e-mail. ****************** SECOND CALL FOR PARTICIPATION ******************** Fourth International Symposium on Formal Methods for Components and Objects (FMCO 2005) DATES 1 - 4 November 2005 PLACE CWI, Amsterdam, The Netherlands The early registration deadline is about to close (October 15th)! For more information please visit the FMCO web site at http://fmco.liacs.nl/fmco05.html This year's conference program includes: * Eleven outstanding keynote speakers: - Michael Barnett (Microsoft, USA) - Luís Caires (New University of Lisbon, PT) - Dennis Dams (Bell Labs, USA) - Wan Fokkink (Free University, NL) - Orna Grumberg (Technion, ISR) - Joost-Pieter Katoen (RWTH Aachen, DE) - Kung-Kiu Lau (University of Manchester, UK) - Peter O' Hearn (Queen Mary University of London, UK) - Arnd Poetzsch-Heffter (University of Kaiserslautern, DE) - John Reynolds (Carnegie Mellon University, USA) - Davide Sangiorgi (University of Bologna, IT) - Jan van Schuppen (CWI, NL) * Ten selected tutorials For full details see the conference web site http://fmco.liacs.nl/fmco05.html We look forward to see you in Amsterdam. The FMCO 2005 Organizing Committee F.S. de Boer (CWI and LIACS - Leiden University) M.M. Bonsangue (LIACS - Leiden University) S. Graf (Verimag) W.P. de Roever (Kiel University)

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CFP: PAPP 2006
by Clemens Grelck 11 Oct '05

11 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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Call for Contributions - HC&A Report (November 2005 edition)
by Andres Loeh 11 Oct '05

11 Oct '05

Dear Haskellers, it is nearly time for the ninth edition of the ================================================================ Haskell Communities & Activities Report http://www.haskell.org/communities/ Submission deadline: 1 November 2005 (please send your contributions to hcar at haskell.org, in plain ASCII or LaTeX format) ================================================================ This is the short story: * If you are working on any project that is in some way related to Haskell, write a short entry and submit it to the me. * If you are interested any project related to Haskell that has not previously been mentioned in the HC&A Report, please tell me, so that I can contact the project leaders and ask them to submit an entry. * Feel free to pass on this call for contributions to others that might be interested. More detailed information: The Haskell Communities & Activities Report is a bi-annual overview of the state of Haskell as well as Haskell-related projects over the last, and possibly the upcoming 6 months. If you have only recently been exposed to Haskell, it might be a good idea to browse the May 2005 edition -- you will find interesting topics described as well as several starting points and links that may provide answers to many questions. Contributions will be collected until the beginning of November. They will be compiled into a coherent report which will appear sometime during November. As always, this is a great opportunity to update your webpages, make new releases, announce of even start new projects, or to point at some developments you want every Haskeller to see! As the purpose of the report is to collect recent or current activities, I encourage you to update all existing summaries and reports. I will probably drop any topics that have not had any activity for the past year, i.e., since November 2004, but I would very much prefer you to present an updated description of the topic. Of course, new entries are more than welcome. Reports should generally be kept brief and informative, ranging from a few sentences to a few hundred words, to keep the whole report reasonably sized. Looking forward to your contributions, Andres (current editor) ----------------------------------- topics New suggestions for current hot topics, activities, projects, etc. are welcome - especially with names and addresses of potential contacts, but here is a non-exclusive list of likely topics (see also http://www.haskell.org/communities/topics.html ): General Haskell developments Haskell implementations Haskell extensions Standardization Documentation Libraries Papers and Books Feedback Summaries of discussions in specialist mailing lists Conference reports Community activities Other Haskell information channels (TMR, Sequence, HWN, ...) Announcements Everything that's new or has had new releases Ongoing projects Reports on what's happening behind the scenes Confirmations that projects are still maintained Calls for contributions and contributors Tutorials Tools and Applications Released and unreleased Haskell applications Tools useful for Haskell programmers Experiences with using Haskell for a project Commercial uses of Haskell Even if your topic is not listed in this list, there's a good chance it has a place in the Report. Please get in touch with me. If you want to see an entry that hasn't been there in the past, but you are not the maintainer of the project, then please encourage the maintainers to write an entry/update, or ask permission to write the entry yourself. -------------------------- what should I write? That depends on your topic, but as a general rule, it shouldn't take you long. A simple sentence or two about your use of Haskell could go into the "Individual Haskellers" section. If you're a company, or if you're working on a project using Haskell as the implementation language, a paragraph on that could go into the "Applications" section. A typical summary report about a tool/library/project/application/... would be between 1 and 3 paragraphs of ASCII text (what's it about? major topics and results since the last report? current hot topics? major goals for the next six months?) plus pointers to material for further reading (typically to a home page, or to mailing list archives, specifications and drafts, implementations, meetings, minutes, ...). Browsing through previous editions should give you a good idea of the variety of possibilities, ranging from very brief to extensive. For those who prefer templates to fill in, the report is edited in LaTeX, and an entry template might look something like this: \begin{hcarentry}{<MYSTUFF>} \report{<MY NAME>} \status{<PROJECT STATUS IN ONE LINE>} \makeheader <WHAT IS IT?> <WHAT IS ITS STATUS? / WHAT HAS HAPPENED SINCE LAST TIME?> <CAN OTHERS GET IT?> <WHAT ARE THE IMMEDIATE PLANS?> \FurtherReading \url{<PROJECT URL>} \end{hcarentry} A style file to preview your document using this template is available at http://haskell.org/communities/11-2005/hcar.sty

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A haddock question
by Benjamin Franksen 10 Oct '05

10 Oct '05

Hello, I have a module with a public class plus some instances for public data types. In addition, I use this class inside another module where I declare local (module private) data types and make them instances of the class. I had expected that haddock (I am using 0.7) will list in the documentation only instances of data types that are exported, but instead all instances are listed. Is there a way to persuade haddock to list only instances of data types that are actually visible to the user? Ben

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RE: [Haskell] A haddock question
by Simon Marlow 10 Oct '05

10 Oct '05

[please excuse premature send.] On 10 October 2005 12:44, Benjamin Franksen wrote: > I have a module with a public class plus some instances for public > data types. In addition, I use this class inside another module where > I declare local (module private) data types and make them instances of > the class. I had expected that haddock (I am using 0.7) will list in > the documentation only instances of data types that are exported, but > instead all instances are listed. > > Is there a way to persuade haddock to list only instances of data > types that are actually visible to the user? Haddock's support for instances is somewhat braindead - it just reports all the instances it can find for a given class in the entire set of modules it is processing. In particular, Haddock makes no attempt to tell you how to bring these instances into scope: they might not be available from the module that exports the class, or the type(s), involved in the instance. Haskell makes this quite hard: an instance is available if it is provided by the transitive closure of an imported module. We clearly don't want to report all the available instances in every module's documentation, however. We probably don't want to document every module from which an instance is available either. Nevertheless, doing one of these two would be "correct". I'm open to suggestions. Benjamin: your example is probably more simple, Haddock probably just shouldn't be exposing those instances if they refer to non-exported types, I just wanted to point out the more general problem. Cheers, Simon

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ANN: MissingH 0.12.0 (Better binary file support)
by John Goerzen 10 Oct '05

10 Oct '05

MissingH 0.12.0 is now available. Changes from 0.11.5 include: * MissingH.IO.Binary can now work with Strings or [Word8], instead of just strings. This support is implemented with a typeclass, so the module is fully backwards-compatible. * MissingH.IO.Binary can now work with any HVIO object, not just Handles. * New support for binary I/O in MissingH.IO.HVIO and HVFS. * Updated BlockIO and Threads.Child to 2005-02-14 versions from Peter. * MissingH.IO.Binary.hBlockCopy optimized to require no conversion of the buffer. * Fixed docs to work with Haddock 0.7 * New module MissingH.Daemon to support detaching from a controlling terminal * New simplegrep.hs example MissingH homepage: http://quux.org/devel/missingh or gopher://quux.org/1/devel/missingh MissingH source and Debian packages are also available from any Debian mirror, such as: http://http.us.debian.org/debian/pool/main/m/missingh (There is approximately a 48-hour delay before new versions appear there.) Currently in development for MissingH 0.13.0: * Native Haskell support for creating and extracting tar files * E-mail mailbox abstraction and implementation for Maildirs and MBOXes -- John Goerzen Author, Foundations of Python Network Programming http://www.amazon.com/exec/obidos/tg/detail/-/1590593715

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RE: [Haskell] SPJ book - big idea behind supercombinator reductionrestriction
by Simon Peyton-Jones 10 Oct '05

10 Oct '05

| Is it crucial just for reasons of efficiency - and in actual fact it's | entirely possible, albeit inefficient, to instantiate one variable at a | time? That's exactly right. Simon

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RE: [Haskell] A haddock question
by Simon Marlow 10 Oct '05

10 Oct '05

On 10 October 2005 12:44, Benjamin Franksen wrote: > I have a module with a public class plus some instances for public > data types. In addition, I use this class inside another module where > I declare local (module private) data types and make them instances of > the class. I had expected that haddock (I am using 0.7) will list in > the documentation only instances of data types that are exported, but > instead all instances are listed. > > Is there a way to persuade haddock to list only instances of data > types that are actually visible to the user? Haddock's support for instances is somewhat braindead - it just reports all the instances it can find for a given class in the entire set of modules it is processing. In particular, Haddock makes no attempt to tell you how to bring these instances into scope: they might not be available from the module that exports the class, or the type(s), involved in the instance. Haskell makes this quite hard: an instance is available if it is provided by the transitive closure of an imported module. We clearly don't want to report all the available instances in every module's documentation, however. This is exposes to the user

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SPJ book - big idea behind supercombinator reduction restriction
by paul boston 08 Oct '05

08 Oct '05

Simon Peyton Jones's book "The Implementation of Functional Programming Languages", chapter 13 (Supercombinators and Lamba-lifting), page 222, describes a "multi-argument" beta-reduction strategy whereby several free variables of a multi-argument abstraction may be instantiated simultaneously. Then, on page 225 the following sentence appears: "A crucial point in the definition of a supercombinator given above is that a supercombinator reduction only takes place when all the arguments are present." I feel that there's some big idea in the pages between these two references, but I can't quite grasp it. I can appreciate that there are good reasons (e.g. efficiency) to instantiate several variables at once, but I don't quite understand why this restriction is "crucial". Is it crucial just for reasons of efficiency - and in actual fact it's entirely possible, albeit inefficient, to instantiate one variable at a time? Or is it, given that the whole point of supercombinators is to allow compilation to fixed code sequences for the G-machine, that there is a good reason to avoid having these fixed code sequences deal with instantiating one free variable at a time (simplicity of design, or some kind of restriction on the way that G-machine operations work)? Or is there a deeper theoretical reason related to the combinators themselves that has nothing to do with the downstream compilation process? _________________________________________________________________ Be the first to hear what's new at MSN - sign up to our free newsletters! http://www.msn.co.uk/newsletters

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