July 2006 - Haskell - Haskell.org

ANN: System.FilePath 0.9
by Neil Mitchell 14 Jul '06

14 Jul '06

Hi, I have written a System.FilePath module in part based on the one in Yhc, and in part based on the one in Cabal (thanks to Lemmih). The aim is to try and get this module into the base package, as FilePath's are something many programs use, but its all too easy to hack up a little function that gets it right most of the time on most platforms, and there lies a source of bugs. This module is Posix (Linux) and Windows capable - just import System.FilePath and it will pick the right one. Of course, if you demand Windows paths on all OS's, then System.FilePath.Windows will give you that (same with Posix). Written in Haskell 98 + Heirarchical Modules. Homepage: http://www-users.cs.york.ac.uk/~ndm/projects/libraries.php Haddock: http://www-users.cs.york.ac.uk/~ndm/projects/filepath/System-FilePath.html Darcs: darcs get http://www.cs.york.ac.uk/fp/darcs/filepath Source: http://www.cs.york.ac.uk/fp/darcs/filepath/System/FilePath.hs Tests: http://www.cs.york.ac.uk/fp/darcs/filepath/Tests.hs Readme: http://www.cs.york.ac.uk/fp/darcs/filepath/readme.txt If you go to the haddock page there are a few little examples at the top of the file. The Yhc project, hquickfile and a few other utilites are already using this module succesfully. Comments welcome. Thanks Neil

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ANN: Takusen 0.5
by Alistair Bayley 14 Jul '06

14 Jul '06

Oleg and I are pleased to announce the release of a new version of Takusen (it's been a while; so long that we don't remember the last version number we used). The most significant code change is a new internal design (courtesy of Oleg) which gives better separation of concerns like statement preparation, binding, and result-set processing. Also of note is a conversion to darcs, and hosting at haskell.org (thanks to Simon Marlow): darcs get http://darcs.haskell.org/takusen ... which also has the nice property that the Haddock documentation is browseable online: http://darcs.haskell.org/takusen/doc/html/index.html A comprehensive description of API usage can be found in the documentation for module Database.Enumerator: http://darcs.haskell.org/takusen/doc/html/Database-Enumerator.html We hope that the use of darcs will encourage contributions... Other changes: - support for multiple result sets returned from functions (PostgreSQL only). Oracle support for this is in the pipeline, which will allow use of nested cursors, and processing RefCursors returned as output parameters from procedure calls. Future plans: - Cabalisation - use of Data.Time instead of System.Time - ODBC and MS Sql Server backends For those of you unfamiliar with Takusen, here is our HCAR blurb: Takusen is a library for accessing DBMS's. It is a low-level library like HSQL, in the sense that it is used to issue SQL statements. Takusen's "unique-selling-point" is a design for processing query results using a left-fold enumerator. For queries the user creates an iteratee function, which is fed rows one-at-a-time from the result-set. We also support processing query results using a cursor interface, if you require finer-grained control. Currently we fully support Oracle, Sqlite, and PostgreSQL. Alistair

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Type-Level Naturals Like Prolog?
by Jared Warren 14 Jul '06

14 Jul '06

Haskell's type checking language is a logical programming language. The canonical logical language is Prolog. However, Idealised Prolog does not have data structures, and does Peano numbers like: natural(zero). natural(x), succ(x,y) :- natural(y) And I believe (but cannot confirm): succ(zero,y). succ(x,y) :- succ(y,z) Why can't Haskell (with extensions) do type-level Peano naturals in the same fashion? The code would be something like: > data Zero > > class Natural x where > toInt :: x -> Integer > instance Natural Zero where > toInt _ = 0 > instance (Natural x, Succ x y) => Natural y where > toInt y = undefined + 1 > > class Succ x y > instance Succ Zero y > instance Succ x y => Succ y z > > zero = toInt (undefined :: Zero) -- THIS SUCCEEDS > > one = toInt (undefined :: (Succ Zero x) => x) -- THIS FAILS Thanks, Jared Warren

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AngloHaskell: Gathering at Cambridge.
by Lemmih 13 Jul '06

13 Jul '06

Greetings fellow Haskellers, As you may or may not know, the great folks at Microsoft Research are interviewing people from the end of this month to the 11th of August. In light of this event, I hereby call attention to the AngloHaskell gathering: http://haskell.org/haskellwiki/AngloHaskell Everyone is welcome. Our agenda includes beer, hacking and other fun. -- Friendly, Lemmih

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Last CFP (4 days left): 2nd Int'l Workshop on Automated Specification and Verification of Web Systems (WWV'06)
by Santiago Escobar 12 Jul '06

12 Jul '06

[ We apologize for multiple copies ] ******************************************************************* 2nd International Workshop on Automated Specification and Verification of Web Systems (WWV'06) Cyprus, November 15-19, 2006 (Track of ISoLA 2006) http://www.dsic.upv.es/workshops/wwv06 ******************************************************************* SCOPE The increased complexity of Web sites and the explosive growth of Web-based applications has turned their design and construction into a challenging problem. Nowadays, many companies have diverted their Web sites into interactive, completely-automated, Web-based applications (such as Amazon, on-line banking, or travel agencies) with a high complexity that requires appropriate specification and verification techniques and tools. Systematic, formal approaches to the analysis and verification can address the problems of this particular domain with automated and reliable tools that also incorporate semantic aspects. We solicit paper on formal methods and techniques applied to Web sites, Web services or Web-based applications, such as: * rule-based approaches to Web site analysis, certification, specification, verification, and optimization * formal models for describing and reasoning about Web sites * model-checking, synthesis and debugging of Web sites * abstract interpretation and program transformation applied to the semantic Web * intelligent tutoring and advisory systems for Web specifications authoring The WWV series provides a forum for researchers from the communities of Rule-based programming, Automated Software Engineering, and Web-oriented research to facilitate the cross-fertilization and the advancement of hybrid methods that combine the three areas. LOCATION WWV'06 will be held in November in Cyprus as a Special Track of the 2006 International Symposium on Leveraging Applications of Formal Methods, Verification, and Validation (ISoLA 2006). SUBMISSION PROCEDURE Submissions must be received by July 16, 2006. Submitted papers should be at most 15 pages in the Lecture Notes in Computer Science (LNCS) style. Submitted papers should include an abstract and the author's information. See the author's instructions of LNCS style at http://www.springer.de/comp/lncs/authors.html. PUBLICATION Accepted papers will be published in a preliminary proceedings volume, which will be available during the workshop. Publication of the workshop post-proceedings by IEEE Computer Society Press is envisaged. PROGRAM CO-CHAIRS Maria Alpuente (Technical University of Valencia, Spain) Moreno Falaschi (University of Siena, Italy) WORKSHOP CHAIR Santiago Escobar (Technical University of Valencia, Spain) PROGRAM COMMITTEE Jose Julio Alferes (Universidade Nova de Lisboa, Portugal) Maria Alpuente (Technical University of Valencia, Spain) Demis Ballis (University of Udine, Italy) Francois Bry (University of Munich, Germany) Santiago Escobar (Technical University of Valencia, Spain) Francois Fages (INRIA Rocquencourt, France) Moreno Falaschi (University of Siena, Italy) Gopal Gupta (University of Texas at Dallas, USA) Shriram Krishnamurthi (Brown University, USA) Tiziana Margaria (University of Potsdam, Germany) I.V. Ramakrishnan (State University of New York at Stony Brook, USA) Leon van der Torre (University of Luxembourg, Luxembourg) IMPORTANT DATES Paper Submission July 16, 2006 Acceptance Notification September 17, 2006 Camera Ready October 15, 2006 Workshop November 15-19, 2006 (one day)

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Lrc status
by Robert Dockins 12 Jul '06

12 Jul '06

Does anyone have any information about the current status of Lrc? Has it ever been released? Does it live somewhere else now? The homepage is apparently: http://www.di.uminho.pt/~jas/Research/ LRC/lrc.html It has a bunch of "coming soon" links, but the page hasn't been updated since about 2002. Rob Dockins Speak softly and drive a Sherman tank. Laugh hard; it's a long way to the bank. -- TMBG

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crash unsafeperformio stm
by Johannes Goetz 12 Jul '06

12 Jul '06

hi folks, i'm using ghc6 (apt-get install ghc6) on debian31. as far is i understand, the following program shouldn't crash. can somebody tell me why it does? thanks a lot. johannes. module Main(main) where import Control.Concurrent.STM import System.IO.Unsafe {-# NOINLINE a #-} a :: TMVar Int a = unsafePerformIO $ atomically $ newTMVar 123 main = do atomically $ takeTMVar a >>= putTMVar a ghc --make -fno-cse Test.hs -o test ./test Segmentation fault

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Yampa Arcade
by Dominic Steinitz 11 Jul '06

11 Jul '06

Does anyone know where the source code for Yampa Arcade can be found? Googling "yampa arcade" turned up this http://www.cs.hmc.edu/courses/2006/spring/cs182-3/afrp/ but I was expecting to find it stand alone rather than as part of a lecture course. Thanks, Dominic.

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Re: [Haskell] Can someone provide a summary of best Sudoku solver times?
by Chris Kuklewicz 10 Jul '06

10 Jul '06

Taral wrote: > On 7/9/06, Chris Kuklewicz <haskell(a)list.mightyreason.com> wrote: >> I improved the speed and strength of my solver and it finishes the >> 36638 puzzles >> of http://www.csse.uwa.edu.au/~gordon/sudoku17 in 3885 seconds. It >> can solve >> all but 164 without guessing, and averages greater 9 puzzles per >> second on a >> 1.33 GHz PPC Mac OS X laptop using ghc-6.4.2 > > Is this the DLX solver on the wiki? > Not quite. This is an optimized, bug-fixed, and more powerful solver. I will update the wiki version soon. -- Chris

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IFL 2006: Paper submission and registration deadline approaching
by HORVATH Zoltan 10 Jul '06

10 Jul '06

THIRD ANNOUNCEMENT and CALL FOR PAPERS !!! PAPER SUBMISSION AND REGISTRATION DEADLINE APPROACHING !!! The registration site: http://www.inf.elte.hu/rendezvenyek/ifl/registration.htm ************************************************************** * 18th International Symposium on * * Implementation and Application of Functional Languages * * IFL 2006 * * * * September 4-6, 2006 * * Budapest, Hungary * * http://plc.inf.elte.hu/ifl2006 * * * * Hosted by the * * Department of Programming Languages and Compilers of * * the Faculty of Informatics at Eotvos Lorand University * ************************************************************** --------- IMPORTANT DATES --------- * July 30th 2006 Registration deadline * Aug 4th 2006 Submission deadline for draft proceedings * Oct 24th 2006 Submission deadline for post-refereeing process * Dec 8th 2006 Notification of acceptance/rejection * Jan 31th 2007 Camera-ready papers ---------------------------------------------------------------- Scope and Topics The IFL workshops form a tradition that has lasted for nearly two decades. The aim of these workshops is to bring together researchers actively engaged in the implementation and application of functional and function-based programming languages. They provide an open forum for researchers who wish to present and discuss new ideas and concepts, work in progress, preliminary results, etc. related primarily but not exclusively to the implementation and application of functional languages. IFL becomes symposium from 2006. Topics of interest include, but are not limited to: * language concepts * concurrent/parallel programming * type checking * concurrent/parallel program execution * compilation techniques * heap management * generic programming techniques * runtime profiling * (abstract) interpretation * performance measurements * automatic program generation * debugging and tracing * (abstract) machine architectures * verification * formal aspects * tools and programming techniques * array processing * demos of well working, useable tools and applications in functional languages Papers on applications demonstrating the suitability of novel ideas in any of the above areas and contributions on related theoretical work are also welcomed. The change of the workshop name adding the term "application", introduced in 2004, is to reflect the broader scope IFL has gained over recent years. Prospective authors are encouraged to submit papers to be published in the draft proceedings and to give presentations at the workshop. All contributions must be written in English, conform to the Springer-Verlag LNCS series format. Attendees at IFL'06 will have an opportunity to submit a revised version of their paper for post-workshop reviewing. Selected papers will be published by Springer Verlag in the well-known Lecture Notes in Computer Science (LNCS) Series, as has been a long-standing tradition for the IFL. Programme Committee Matthias Blume Toyota Technological Institute, Chicago, USA Zoran Budimac University of Novi Sad, Serbia Andrew Butterfield Trinity College Dublin, Ireland Ralf Hinze University of Bonn, Germany Zoltan Horvath Eotvos Lorand University, Budapest, Hungary (Chair) Tamas Kozsik Eotvos Lorand University, Budapest, Hungary Hans-Wolfgang Loidl Ludwig-Maximilians-University Munich, Germany Rita Loogen Philipps-University Marburg, Germany Frederic Loulergue University of Orleans, France Simon Marlow Microsoft Research, Cambridge, UK Marco Morazan Seton Hall University, New Jersey, USA Yolanda Ortega-Mallen University Complutense of Madrid, Spain Rinus Plasmeijer Radboud University Nijmegen, The Netherlands Jaroslav Poruban Technical University of Kosice, Slovakia Anna Soos Babes-Bolyai University, Cluj-Napoca, Romania Doaitse Swierstra Utrecht University, The Netherlands Peter Thiemann University of Freiburg, Germany German Vidal Technical University of Valencia, Spain Symposium Organization Zoltan Horvath, Viktoria Zsok Department of Programming Languages and Compilers Faculty of Informatics Eotvos Lorand University, Budapest, Hungary Further information Web-site: http://www.inf.elte.hu/rendezvenyek/ifl/ E-mail: ifl2006(a)inf.elte.hu

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