- Haskell - Haskell.org

Summer of code Haddock complains about module "which is not loaded"
by Mads Lindstrøm 07 Aug '07

07 Aug '07

Hi all I am trying to use the summer of code version of haddock, which I got from the Darcs repository. I have two files: Bar.hs: module Bar where -- |Some comment bar :: Int bar = 2 and Foo.hs: module Foo where import Bar -- |Some comment. foo :: Int foo = bar + 5 when I run haddock like: > haddock -h -ohtml -B/usr/local/lib/ghc-6.7.20070729/ Foo.hs Bar.hs it complains with: Warning: Cannot use package base: HTML directory $topdir/share/ghc/doc/html/base does not exist. argument targets: Foo.hs Bar.hs all targets: Bar.hs Foo.hs Foo.hs:3:0: attempting to use module `Bar' (Bar.hs) which is not loaded haddock: Failed to check all modules properly make: *** [doc] Fejl 1 Why is it Haddock cannot find the Bar module? After all I mention Bar.hs in the invocation of haddock. Greetings, Mads Lindstrøm

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Haskell Weekly News: August 07, 2007
by dons＠cse.unsw.edu.au 07 Aug '07

07 Aug '07

--------------------------------------------------------------------------- Haskell Weekly News http://sequence.complete.org/hwn/20070807 Issue 64 - August 07, 2007 --------------------------------------------------------------------------- Welcome to issue 64 of HWN, a weekly newsletter covering developments in the [1]Haskell community. This issue marks the second anniversary of the Haskell (not quite) Weekly News. Thanks to the Haskell community for support, content and for reading over the last two years! 1. http://haskell.org/ Announcements OSCON Haskell Tutorial. Simon Peyton-Jones Appeared at the O'Reilly Open Source Convention (OSCON) in Portland, delivering a range of talks, including [2]A Taste of Haskell, [3]A Keynote on Functional Languages, [4]Nested Data Parallelism and [5]Transactional Memory for Concurrent Programming. Videos are available for most of these talks: [6]A Taste of Haskell: Part 1, [7]A Taste of Haskell: Part 2, [8]slides for A Taste of Haskell, [9]Transactional Memory for Concurrent Programming and [10]the NDP talk at the London Hugs meeting. 2. http://conferences.oreillynet.com/cs/os2007/view/e_sess/14016 3. http://conferences.oreillynet.com/cs/os2007/view/e_sess/14773 4. http://conferences.oreillynet.com/cs/os2007/view/e_sess/14014 5. http://conferences.oreillynet.com/cs/os2007/view/e_sess/14017 6. http://blip.tv/file/324976 7. http://www.blip.tv/file/325646/ 8. http://conferences.oreillynet.com/presentations/os2007/os_peytonjones.pdf 9. http://www.blip.tv/file/317758/ 10. http://video.google.co.uk/videoplay?docid=370317485066035666 hpodder 1.0. John Goerzen [11]announced version 1.0.0 of hpodder, the command-line podcatcher (podcast downloader) that just happens to be written in everyone's favorite language. You can get it [12]here. Version 1.0.0 sports a new mechanism for detecting and disabling feeds or episodes that repeatedly result in errors, updates to the Sqlite database schema, and several bugfixes. 11. http://article.gmane.org/gmane.comp.lang.haskell.general/15452 12. http://software.complete.org/hpodder encoding-0.1. Henning Günther [13]announced the release of 'encoding', a Haskell library to cope with many character encodings found on modern computers. At the moment it supports (much more is planned): ASCII, UTF-8, -16, -32, ISO 8859-* (alias latin-*), CP125* (windows codepages), KOI8-R, Bootstring (base for punycode) 13. http://article.gmane.org/gmane.comp.lang.haskell.general/15481 Dimensional 0.6: Statically checked physical dimensions. Björn Buckwalter [14]announced a library providing data types for performing arithmetic with physical quantities and units. Information about the physical dimensions of the quantities/units is embedded in their types and the validity of operations is verified by the type checker at compile time. The boxing and unboxing of numerical values as quantities is done by multiplication and division with units. 14. http://article.gmane.org/gmane.comp.lang.haskell.cafe/26944 Hackage This week's new libraries in [15]the Hackage library database. * hgal-1.0.1. Jean Philippe Bernardy. [16]Computation automorphism group and canonical labeling of a graph * hpodder-1.0.3. John Goerzen. [17]Podcast Aggregator (downloader) * dlist-0.3.1. Don Stewart. [18]Differences lists: a list-like type supporting O(1) append * pointfree-1.0. Felix Martini. [19]Stand-alone command-line version of the point-less plugin for lambdabot * encoding-0.1. Henning Guenther. [20]A library for various character encodings * AppleScript-0.1.3. Wouter Swierstra. [21]Call AppleScript from Haskell * SDL-ttf-0.4.0. David Himmelstrup. [22]Binding to libSDL_ttf * Finance-Quote-Yahoo-0.2. Brad Clawsie. [23]Obtain quote data from finance.yahoo.com * xmobar-0.7. Andrea Rossato. [24]A Minimalistic Text Based Status Bar 15. http://hackage.haskell.org/ 16. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hgal-1.0.1 17. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hpodder-1.0.3 18. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/dlist-0.3.1 19. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/pointfree-1.0 20. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/encoding-0.1 21. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/AppleScript-0.1.3 22. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/SDL-ttf-0.4.0 23. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Finance-Quote-Ya… 24. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/xmobar-0.7 Conference roundup OSCON. Simon Peyton-Jones gave a series of popular talks about Haskell and functional programming at OSCON, in Portland. Below are collected just some of the posts about Haskell at OSCON. * [25]A brief Haskell-at-OSCON trip report * [26]Wow! OSCON video viewing statistics * [27]OSCon Wednesday Part 2 * [28]A Taste of Haskell, A Taste of C * [29]OSCON Day 1 * [30]A Taste of Haskell * [31]OSCON 2007 * [32]Threading Building Blocks and C++ * [33]OSCON: Wednesday Morning * [34]OSCON: Wednesday Afternoon * [35]OSCON 2007 (July 25) * [36]Nested Data Parallelism in Haskell * [37]OSCON 2007: Wednesday Morning Keynotes * [38]A Taste of Haskell 25. http://www.realworldhaskell.org/blog/2007/08/03/a-brief-haskell-at-oscon-tr… 26. http://www.realworldhaskell.org/blog/2007/08/07/wow-oscon-video-viewing-sta… 27. http://changelog.complete.org/posts/632-OSCon-Wednesday-Part-2.html 28. http://www.oreillynet.com/onlamp/blog/2007/07/a_taste_of_haskell_a_taste_of… 29. http://brycebaril.vox.com/library/post/oscon-2007-day-1.html 30. http://jaortega.wordpress.com/2007/08/04/a-taste-of-haskell/ 31. http://www.sauria.com/blog/2007/08/03/oscon-2007/ 32. http://softwareblogs.intel.com/2007/07/26/threading-building-blocks-and-c/ 33. http://znark.com/blog/2007/07/25/oscon-wednesday-morning 34. http://znark.com/blog/2007/07/25/oscon-wednesday-afternoon 35. http://panela.blog-city.com/oscon_2007_july_25.htm 36. http://ihack.us/2007/07/25/nested-data-parallelism-in-haskell/ 37. http://www.canspice.org/2007/07/25/oscon-2007-wednesday-morning-keynotes/ 38. http://butlerpress.com/2007/07/24/a-taste-of-haskell/ Blog noise [39]Haskell news from the [40]blogosphere. * [41]Ord, Countable Ordinals, and an Idea of sigfpe * [42]Word numbers, Part 1: Billion approaches * [43]Implementing SmallTalk in Haskell * [44]From walking to zipping, Part 1: Moving right * [45]From walking to zipping, Part 2: Down and up * [46]Irrefutable patterns for the ignorant * [47]Making Haskell nicer for game programming * [48]Nested Data Parallelism in Haskell * [49]Compiling Haskell to Erlang * [50]Peano's Axioms IV: Advanced Functions and Integers * [51]37 Reasons to Love Haskell * [52]On the value of strong static typing * [53]Parsec Parser Testing with QuickCheck * [54]Fallacies in the Great Dynamic vs Static Debate * [55]Implementing a dictionary using first class functions * [56]Strong specifications in Coq: the type says everything * [57]Run length encoding in Haskell * [58]Run length encoding and arrows * [59]Playing with Arrows * [60]Monads! (and Why Monad Tutorials Are All Awful) * [61]Haskell: Explaining Arrows through XML Transformations * [62]Monads as computation * [63]Closed Categories * [64]Good Haskell Style * [65]Monads are hard to teach * [66]Parsec * [67]First attempt at using GTK with Haskell * [68]Introduction to Haskell, Part 3: Monads * [69]Programming in Haskell * [70]Haskell Fun * [71]Algebraic Data Types again * [72]DFAs, Categories, and Typecheckers * [73]Haskell State Accessors (second attempt: Composability) * [74]Developing Programs and Proofs Spontaneously using GADT * [75]Encoding Inductive and Coinductive Types in Polymorphic Lambda Calculus * [76]Polymorphic Types in Haskell without Constructors? * [77]Subtraction not Definable in Simply Typed Lambda Calculus * [78]Imperative programming is a special type of functional programming * [79]Binding Haskell to C structs 39. http://planet.haskell.org/ 40. http://haskell.org/haskellwiki/Blog_articles 41. http://blog.jbapple.com/2007/07/ord-countable-ordinals-and-idea-of.html 42. http://conway.rutgers.edu/~ccshan/wiki/blog/posts/WordNumbers1/ 43. http://lstephen.wordpress.com/2007/07/23/completing-the-spike/ 44. http://conway.rutgers.edu/~ccshan/wiki/blog/posts/WalkZip1/ 45. http://conway.rutgers.edu/~ccshan/wiki/blog/posts/WalkZip2/ 46. http://therning.org/magnus/archives/311 47. http://luqui.org/blog/archives/2007/07/26/making-haskell-nicer-for-game-pro… 48. http://ihack.us/2007/07/25/nested-data-parallelism-in-haskell/ 49. http://blog.tornkvist.org/?id=1185571582964040 50. http://disparatemathematician.blogspot.com/2007/07/peanos-axioms-iv-advance… 51. http://cdsmith.wordpress.com/2007/07/29/37-reasons-to-love-haskell-playing-… 52. http://www.serpentine.com/blog/2007/07/29/on-the-value-of-strong-static-typ… 53. http://lstephen.wordpress.com/2007/07/29/parsec-parser-testing-with-quickch… 54. http://neilbartlett.name/blog/2007/07/30/fallacies-in-the-great-dynamic-vs-… 55. http://lukeplant.me.uk/blog.php?id=1107301671 56. http://www.rubrication.net/2007/04/24/strong-specifications/ 57. http://cgi.cse.unsw.edu.au/~dons/blog/2007/07/31#rle 58. http://community.livejournal.com/evan_tech/229752.html 59. http://unenterprise.blogspot.com/2007/08/playing-with-arrows.html 60. http://ahamsandwich.wordpress.com/2007/07/26/monads-and-why-monad-tutorials… 61. http://neilbartlett.name/blog/2007/08/01/haskell-explaining-arrows-through-… 62. http://www.haskell.org/haskellwiki/Monads_as_computation 63. http://unapologetic.wordpress.com/2007/08/01/closed-categories/ 64. http://urchin.earth.li/~ian/style/haskell.html 65. http://davblog48.blogspot.com/2007/08/monads-are-hard-to-teach.html 66. http://davblog48.blogspot.com/2007/05/parsec.html 67. http://davblog48.blogspot.com/2007/05/first-attempt-at-using-gtk-with-haske… 68. http://www.onlamp.com/pub/a/onlamp/2007/08/02/introduction-to-haskell-pure-… 69. http://www.cs.chalmers.se/Cs/Grundutb/Kurser/d1pt/d1pta/external.html 70. http://changelog.complete.org/posts/640-guid.html 71. http://blog.tmorris.net/algebraic-data-types-again/ 72. http://disparatemathematician.blogspot.com/2007/08/dfas-categories-and-type… 73. http://luqui.org/blog/archives/2007/08/05/haskell-state-accessors-second-at… 74. http://www.iis.sinica.edu.tw/~scm/?p=32 75. http://www.iis.sinica.edu.tw/~scm/?p=31 76. http://www.iis.sinica.edu.tw/~scm/?p=28 77. http://www.iis.sinica.edu.tw/~scm/?p=27 78. http://blog.tmorris.net/imperative-programming-is-a-special-type-of-functio… 79. http://therning.org/magnus/archives/315 Quotes of the Week * schluehk: ... Haskell taking over the world and troubled parents ask why their kids have turned into math hippies talking about nothing but love and abstract algebra... * JohnGoerzen: Haskell manipulates functions with the same ease that Perl manipulates strings * (anonymous Russian blogger): Glory to Simons! Glory to Swedish professors! * Laurent Sansonetti: I appreciated so much the Haskell talks that I am now learning the language. * dcoutts: Apparently that's only 200x faster than the faster of two common python serialisation libs, so we've got some way to go yet. * slava: [on Isabelle for web frameworks] IM IN UR WEB SITEZ, CODING PROVABLY-CORRECT BLINK TAG!! * gimboland: At present i'd say 'tinkering with a nuclear bomb' is approximately where i am with monads... * jcreigh: Could not find instance Ord for type ProgrammingLanguage * kowey: i suspect we're one of the rare wikibooks to use higher order templates * monochrom: 'm a -> (a -> m b) -> m b' is much more to the point than 'mumble computation mumble computation mumble computation mumble' * roconnor: damn it, Haskell pseudo code is indistinguishable from actual code * slava: Because top enterprise industry analysts recommend Because top enterprise industry analysts recommend that managers need to focus on Agile methodologies, SOA, B2B and Yoneda's lemma in today's rich internet application-driven environment. Don't get left behind by the AJAX craze by missing out on call center outsourcing and Yoneda's lemma! Code Watch Notable new features and bug fixes to the Haskell compilers. Fri Jul 27 03:41:57 PDT 2007. Simon Marlow. Pointer Tagging. This patch implements pointer tagging as per our ICFP'07 paper 'Faster laziness using dynamic pointer tagging'. It improves performance by 10-15% for most workloads, including GHC itself. The original patches were by Alexey Rodriguez Yakushev, with additions and improvements by me. I've re-recorded the development as a single patch. The basic idea is this: we use the low 2 bits of a pointer to a heap object (3 bits on a 64-bit architecture) to encode some information about the object pointed to. For a constructor, we encode the 'tag' of the constructor (e.g. True vs. False), for a function closure its arity. This enables some decisions to be made without dereferencing the pointer, which speeds up some common operations. In particular it enables us to avoid costly indirect jumps in many cases. More information [80]in the commentary. 80. http://hackage.haskell.org/trac/ghc/wiki/Commentary/Rts/HaskellExecution/Po… About the Haskell Weekly News Each week, new editions are posted to [81]the Haskell mailing list as well as to [82]the Haskell Sequence and [83]Planet Haskell. [84]RSS is also available, and headlines appear on [85]haskell.org. Headlines are available as [86]PDF. To help create new editions of this newsletter, please see the [87]contributing information. Send stories to dons at cse.unsw.edu.au. The darcs repository is available at darcs get [88]http://www.cse.unsw.edu.au/~dons/code/hwn 81. http://www.haskell.org/mailman/listinfo/haskell 82. http://sequence.complete.org/ 83. http://planet.haskell.org/ 84. http://sequence.complete.org/node/feed 85. http://haskell.org/ 86. http://www.cse.unsw.edu.au/~dons/code/hwn/archives/20070807.pdf 87. http://haskell.org/haskellwiki/HWN 88. http://www.cse.unsw.edu.au/~dons/code/hwn

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[Fwd: PADL 2008: Call for Papers]
by Paul Hudak 06 Aug '07

06 Aug '07

-------- Original Message -------- Subject: PADL 2008: Call for Papers Date: Sat, 4 Aug 2007 19:25:58 -0500 (CDT) From: Gopal Gupta <gupta(a)utdallas.edu> [ Colleagues, note that this will be the 10th PADL; We strongly urge you to submit papers, the deadline is only 3 weeks way] CALL FOR PAPERS!!! Tenth International Symposium on Practical Aspects of Declarative Languages 2008 (PADL '08) http://www.ist.unomaha.edu/padl2008/ San Francisco, USA January 7-8, 2008 Co-located with ACM POPL'08 Declarative languages build on sound theoretical bases to provide attractive frameworks for application development. These languages have been successfully applied to vastly different real-world situations, ranging from data base management to active networks to software engineering to decision support systems. New developments in theory and implementation have opened up new application areas. At the same time, applications of declarative languages to novel problems raises numerous interesting research issues. Well-known questions include designing for scalability, language extensions for application deployment, and programming environments. Thus, applications drive the progress in the theory and implementation of declarative systems, and benefit from this progress as well. PADL is a forum for researchers and practitioners to present original work emphasizing novel applications and implementation techniques for all forms of declarative concepts, including, functional, logic, constraints, etc. Topics of interest include: * innovative applications of declarative languages; * declarative domain-specific languages and applications; * practical applications of theoretical results; * new language developments & their impact on applications; * evaluation of implementation techniques on practical applications; * novel uses of declarative languages in the classroom; and * practical experiences PADL 08 welcomes new ideas and approaches pertaining to applications and implementation of declarative languages. PADL 08 will be co-located with the ACM POPL. IMPORTANT DATES AND SUBMISSION GUIDELINES Paper Submission: August 24, 2007 Notification: September 27, 2007 Camera-ready: October 23, 2007 Symposium: January 7-8, 2008 Authors should submit an electronic copy of the full paper (written in English) in Postscript (Level 2) or PDF. Papers must be no longer than 15 pages, written in 11-point font and with single spacing. Since the final proceedings will be published as Lecture Notes in Computer Science by Springer Verlag, authors are strongly encouraged to use the LNCS paper formatting guidelines for their submission. Each submission must include on its first page the paper title; authors and their affiliations; contact author's email and postal addresses, telephone and fax numbers, abstract, and three to four keywords. The keywords will be used to assist us in selecting appropriate reviewers for the paper. If electronic submission is impossible, please contact the program chair for information on how to submit hard copies. MOST PRACTICAL PAPER AWARD The Most Practical Paper award will be given to the submission that is judged by the program committee to be the best in terms of practicality, originality, and clarity of presentation. The program committee may choose not to make an award, or to make multiple awards. Contacts: For information about papers and submissions, please contact the Program Chair: Paul Hudak PC co-Chair - PADL 2008 Department of Computer Science Yale University P.O. Box 208285 New Haven, CT 06520 - 8285 Email: hudak(a)cs.yale.edu David S. Warren PC co-Chair - PADL 2008 Department of Computer Science Stony Brook University Stony Brook, NY Email: warren(a)cs.sunysb.edu For other information about the conference, please contact: Hai-Feng Guo General Chair - PADL 2008 Department of Computer Science College of Information Science & Technology University of Nebraska at Omaha Omaha, NE, U.S.A. Email: haifengguo(a)mail.unomaha.edu Sponsored by: COMPULOG Americas (http://www.cs.nmsu.edu/~complog) and University of Nebraska at Omaha

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ICFP07 Call for Participation
by Matthew Fluet (ICFP Publicity Chair) 06 Aug '07

06 Aug '07

===================================================================== Call for Participation The 12th ACM SIGPLAN International Conference on Functional Programming (ICFP 2007) http://www.informatik.uni-bonn.de/~ralf/icfp07.html Freiburg, Germany, 1-3 October 2007 ===================================================================== ICFP 2007 provides a forum for researchers and developers to hear about the latest work on the design, implementations, principles, and uses of functional programming. The conference covers the entire spectrum of work, from practice to theory, including its peripheries. Preliminary program: * http://www.informatik.uni-bonn.de/~ralf/schedule.html * Invited speakers: + John Hughes (Chalmers University of Technology) + Frank Pfenning (Carnegie Mellon University) + John Lloyd (Australian National University) * The Program committee has *deliberately* created extra breaks so as to give participants more time to talk with colleagues. Schedule including related workshops: * 30 Sep: ACM SIGPLAN Haskell Workshop * 30 Sep: ACM SIGPLAN Workshop on Scheme and Functional Programming * 1-3 Oct: ICFP07 * 4 Oct: ACM SIGPLAN Commercial Users of Functional Programming * 4 Oct: ACM SIGPLAN Workshop on Mechanizing Metatheory * 5 Oct: ACM SIGPLAN Erlang Workshop * 5 Oct: ACM SIGPLAN Workshop on ML * 5 Oct: ACM SIGPLAN Programming Languages meets Program Verification Registration information: * http://proglang.informatik.uni-freiburg.de/ICFP2007/registration.shtml * Early registration deadline: September 7, 2007 Accommodations information: * http://proglang.informatik.uni-freiburg.de/ICFP2007/accommodation.shtml * Conference reservation/rate deadline: September 1, 2007 * September/October is Freiburg's main tourist season; participants are advised to book rooms as early as possible. Conference organizers: * General Chair: Ralf Hinze (Universität Bonn) * Program Chair: Norman Ramsey (Harvard University) * Local Arrangements Chair: Peter Thiemann (Universität Freiburg) * Workshop Co-Chairs: Graham Hutton (University of Nottingham) and Matthias Blume (Toyota Technological Institute at Chicago) * Programming Contest Chair: Johan Jeuring (Universiteit Utrecht) * Publicity Chair: Matthew Fluet (Toyota Technological Institute at Chicago)

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PEPM 2008
by Oege.de.Moor＠comlab.ox.ac.uk 06 Aug '07

06 Aug '07

PEPM 2008 ACM SIGPLAN Workshop on Partial Evaluation and Program Manipulation January 7-8, 2008, San Francisco Keynotes by Ras Bodik (Berkeley) and Monica Lam (Stanford) Co-located with POPL http://www.program-transformation.org/PEPM08/WebHome PEPM is a leading venue for the presentation of cutting-edge research in program analysis, program generation and program transformation. Its proceedings are published by ACM Press; full details of the scope, submission process, and program committee can be found at the above URL. The program committee would particularly welcome submissions from researchers in functional programming on any topic relating to analysis, optimisation and synthesis of Haskell programs Abstracts are due on October 12, and the deadline for full paper submission is October 17. Prospective authors are welcome to contact the program chairs, Robert Glueck (glueck(a)acm.org) and Oege de Moor (oege(a)comlab.ox.ac.uk) with any queries they might have.

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IFL 2007: Symposium on Implementation and Application of Functional Languages
by Olaf Chitil 03 Aug '07

03 Aug '07

********************************************************************** Call for Papers and Participation 19th International Symposium on Implementation and Application of Functional Languages IFL 2007 27th-29th September 2007, Freiburg, Germany co-located with ICFP 2007 http://proglang.informatik.uni-freiburg.de/IFL2007/ ********************************************************************** ==> Submission for Draft Proceedings 31 August 2007 ==> Early Registration & Hotel Deadline 1 September 2007 The aim of the IFL symposium is to bring together researchers actively engaged in the implementation and application of functional and function-based programming languages. The symposium provides 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. Topics of interest include (but are not limited to): * language concepts * type checking * compilation techniques * (abstract) interpretation * generic programming techniques * automatic program generation * array processing * concurrent/parallel programming * heap management * runtime profiling * performance measurements * debugging and tracing * (abstract) machine architectures * verification * formal aspects * tools and programming techniques Papers on applications or tools demonstrating the suitability of novel ideas in any of the above areas and contributions on related theoretical work are also welcome. The change of the symposium name adding the term "application", introduced in 2004, reflects the broader scope IFL has gained over the years. Contributions Prospective authors are encouraged to submit papers to be published in the draft proceedings and present them at the symposium. All contributions must be written in English, conform to the Springer-Verlag LNCS series format and not exceed 16 pages. The draft proceedings will appear as a technical report. Every attendee of IFL 2007 will have the opportunity to submit a revised version of their paper for post-symposium reviewing. As in previous years, selected papers will be published by Springer Verlag in the Lecture Notes in Computer Science (LNCS) Series. Important Dates Submission for Draft Proceedings 31 August 2007 Early Registration Deadline 1 September 2007 Hotel Registration Deadline 1 September 2007 Symposium 27-29 September 2007 Submission for post-refereeing 2 November 2007 Notification of acceptance / rejection 14 December 2007 Submission of camera-ready version 25 January 2008 Programme Committee Peter Achten Radboud University Nijmegen, The Netherlands Kenichi Asai Ochanomizu University, Japan Manuel Chakravarty The University of New South Wales, Australia Olaf Chitil (chair) University of Kent, UK Martin Erwig Oregon State University, Oregon, USA Marc Feeley Université de Montréal, Canada Martin Gasbichler Zühlke Engineering AG, Switzerland Kevin Hammond University of St. Andrews, Scotland Zoltán Horváth Eötvös Loránd University, Budapest, Hungary John Hughes Chalmers University of Technology, Sweden Ken Friis Larsen University of Copenhagen, Denmark Rita Loogen Philipps-Universität Marburg, Germany Michel Mauny ENSTA, France Sven-Bodo Scholz University of Hertfordshire, UK Clara Segura Universidad Complutense de Madrid, Spain Tim Sheard Portland State University, Oregon, USA Glenn Strong Trinity College, Dublin, Ireland Doaitse Swierstra Utrecht University, The Netherlands Malcolm Wallace The University of York, UK Local Organisation Markus Degen Universität Freiburg, Germany Peter Thiemann Universität Freiburg, Germany Stefan Wehr Universität Freiburg, Germany Further Information http://proglang.informatik.uni-freiburg.de/IFL2007/

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ANNOUNCE: Dimensional 0.6 -- Statically checked physical dimensions
by Björn Buckwalter 02 Aug '07

02 Aug '07

Dear all, I am pleased to announce version 0.6 of the Dimensional library. Dimensional is a library providing data types for performing arithmetic with physical quantities and units. Information about the physical dimensions of the quantities/units is embedded in their types and the validity of operations is verified by the type checker at compile time. The boxing and unboxing of numerical values as quantities is done by multiplication and division with units. The library is designed to, as far as is practical, enforce/encourage best practices [1] of unit usage. Noteworthy changes/additions since the previous formal announcement (version 0.4) are: - All quantities and SI units from [1] have been added. - A Prelude replacement with the SI units and dimensional operators (+, *, ^...) is provided for convenience. - Interface to Data.Time using 'fromDiffTime' and 'toDiffTime'. - Phantom type tags make extended dimensions safer. - Experimental CGS units with type safe conversions to/from SI. See appended literate Haskell module for details. Additional information and code is available from the project web site [3]. Thank you, Bjorn Buckwalter [1] http://physics.nist.gov/Pubs/SP811/ [2] http://www.haskell.org/pipermail/haskell/2007-May/019496.html [3] http://code.google.com/p/dimensional/ ~~~~~~~~~~ BEGIN 'Buckwalter/Dimensional/CGS.lhs' ~~~~~~~~~~ Buckwalter.Dimensional.CGS -- CGS system of units Bjorn Buckwalter, bjorn.buckwalter(a)gmail.com License: BSD3 *** EXPERIMENTAL *** = Introduction = This module was prompted by an email from Chuck Blake[1]. He asked if the Dimensional library could support other systems of units than SI, in particular systems such as the centimeter-gram-second (CGS) system where fractional exponents of dimensions occur. He also wondered whether it was possible to convert quantities between different systems while statically ensuring that a given conversion was valid. In this module we show that we can in a straight forward manner support systems with rational exponents, provided that the rationals that may be encountered are known a priori. As an example we provide a rudimentary implementation of the CGS system. We also show that we can indeed statically prohibit invalid conversions between different systems. = Caveats = I'm ignorantly assuming that when working with the CGS (or MKS) system you will only (meaningfully?) encounter half-exponents and only of the length and mass dimensions. Of course, in other systems other rational exponents may be encountered. I am also assuming that the CGS system would not be employed when working with temperature, amount or luminosity. This is evident in the below type signatures where I have assumed zero extent in the temperature, amount and luminosity dimensions. If this is incorrect I would appreciate pointers to the CGS representation of these dimensions. Please correct and inform me if my assumptions are wrong! = Preliminaries = > {-# OPTIONS_GHC -fglasgow-exts -fallow-undecidable-instances #-} > module Buckwalter.Dimensional.CGS where > import Prelude ( undefined, Num, Fractional, Floating, Show, recip, Double ) > import qualified Prelude > import Buckwalter.Dimensional hiding ( DLength, DMass, DTime, DElectricCurrent ) > import Buckwalter.Dimensional.Quantities as SIQ > import qualified Buckwalter.Dimensional.SIUnits as SI > import qualified Buckwalter.NumType as N > import Buckwalter.NumType ( Neg2, Neg1, Zero, Pos, Pos1, Pos2, Pos3, NumType ) > import Buckwalter.NumType ( neg2, neg1, zero, pos1, pos2, pos3 ) > import Data.Maybe (catMaybes) = Dimensions = Analogously with the SI we collect the base dimensions of the CGS system in the data type 'CGSDim'. > data CGSDim lh mh t In the above 'lh' and 'mh' represent the number of half-exponents of length and mass respectively while 't' represents the number of whole-exponents. The base dimensions illustrate this. > type DLength = CGSDim Pos2 Zero Zero > type DMass = CGSDim Zero Pos2 Zero > type DTime = CGSDim Zero Zero Pos1 We add a few non-base dimensions for the sake of example. Charge is particularly interesting as it illustrates the need for half-exponents as described in [2]. > type DElectricCurrent = CGSDim Pos3 Pos1 Neg2 > type DCharge = CGSDim Pos3 Pos1 Neg1 = 'Mul', 'Div', 'Pow' and 'Root' instances = The 'Mul', 'Div', 'Pow' and 'Root' instances are strictly analogous with the SI. > instance ( N.Sum lh lh' lh'' > , N.Sum mh mh' mh'' > , N.Sum t t' t'' ) => Mul (CGSDim lh mh t) > (CGSDim lh' mh' t') > (CGSDim lh'' mh'' t'') > instance ( N.Sum lh lh' lh'' > , N.Sum mh mh' mh'' > , N.Sum t t' t'' ) => Div (CGSDim lh'' mh'' t'') > (CGSDim lh' mh' t') > (CGSDim lh mh t) > instance ( N.Mul lh x lh' > , N.Mul mh x mh' > , N.Mul t x t' ) => Pow (CGSDim lh mh t) x > (CGSDim lh' mh' t') > instance ( N.Div lh x lh' > , N.Div mh x mh' > , N.Div t x t' ) => Root (CGSDim lh mh t) x > (CGSDim lh' mh' t') = Units = We define the base units of the system. By defining 'meter' with a "scale" of 100 we get a scale of one for 'centi meter'. > meter :: Num a => Unit DLength a > meter = Dimensional 100 > gram :: Num a => Unit DMass a > gram = Dimensional 1 > second :: Num a => Unit DTime a > second = Dimensional 1 We continue by defining the CGS equivalents of the other base SI units. Actually we limit ourselves to 'ampere' since I am not sure if or how the SI base dimensions other than current are expressed in CGS. > ampere :: Floating a => Unit DElectricCurrent a > ampere = prefix (recip 3.33564e-10) ((SI.centi meter ^ pos3) ^/ pos2 * gram ^/ pos2 * second ^ neg2) We also define the preferred CGS unit for charge. > franklin :: Floating a => Unit DCharge a -- Also known as "esu". > franklin = gram ^/ pos2 * (SI.centi meter ^ pos3) ^/ pos2 / second = Conversion from SI = At some point we may wish to convert an SI quantity to a CGS quantity or vice versa. In order to convert a 'Quantity' from the SI system to the CGS system we use the strategy of dividing the quantity by the SI base unit and multiplying the resulting number (sans dimension) by the equivalent CGS unit. To realize this strategy we must be able to obtain the SI base unit and the equivalent CGS unit for a given quantity. We start with the SI unit since it is trivial. > unit_SI :: Num a => Quantity (Dim l m t i th n j) a -> Unit (Dim l m t i th n j) a > unit_SI _ = Dimensional 1 (Perhaps the above function would be better defined in another module.) Obtaining the CGS unit corresponding to the SI base unit of a Quantity isn't quite as trivial. The function body itself is straight-forward enough, the hairy part is the type signature. > unit_CGS :: forall a l m t i l2 m2 il it l' m' t'. > ( Floating a > , N.Mul Zero l Zero, N.Mul Pos2 l l2 > , N.Mul Zero m Zero, N.Mul Pos2 m m2 > , N.Mul Zero t Zero, N.Mul Pos1 t t > , N.Sum l2 Zero l2 > , N.Sum Zero m2 m2, N.Sum m2 Zero m2 > , N.Sum Zero t t > , N.Mul Pos3 i il > , N.Mul Pos1 i i > , N.Mul Neg2 i it > , N.Sum l2 il l' > , N.Sum m2 i m' > , N.Sum t it t' > ) => Quantity (Dim l m t i Zero Zero Zero) a -> Unit (CGSDim l' m' t') a > unit_CGS _ = meter ^ (undefined :: l) > * SI.kilo gram ^ (undefined :: m) > * second ^ (undefined :: t) > * ampere ^ (undefined :: i) Note that since the base dimensions of the CGS are a subset of those of the SI the mapping of types from SI to CGS is unambiguous. Also note that complex as the type signature may be producing it is a mostly mechanical process. With the above two functions we can define the function that converts a unit from the SI. We omit the type signature since it is hairy but can be readily inferred. > fromSI x = x /~ unit_SI x *~ unit_CGS x = Conversion to SI = We use the same strategy to convert from CGS to SI. However, when converting from CGS to SI there may be several valid SI dimensionalities for any given CGS dimensionality. We will handle this ambiguity by requiring the user to specify the desired type (except when it is inferable) of the resulting quantity. For example: ] toSI (3.2 *~ centi meter) :: Length Double In order to do this we must employ lexically scoped type variables and provide the hairy type signature for the 'toSI' function. > toSI :: forall a l m t i l2 m2 il it l' m' t'. > ( Floating a > , N.Mul Zero l Zero, N.Mul Pos2 l l2 > , N.Mul Zero m Zero, N.Mul Pos2 m m2 > , N.Mul Zero t Zero, N.Mul Pos1 t t > , N.Sum l2 Zero l2 > , N.Sum Zero m2 m2, N.Sum m2 Zero m2 > , N.Sum Zero t t > , N.Mul Pos3 i il > , N.Mul Pos1 i i > , N.Mul Neg2 i it > , N.Sum l2 il l' > , N.Sum m2 i m' > , N.Sum t it t' > ) => Quantity (CGSDim l' m' t') a -> Quantity (Dim l m t i Zero Zero Zero) a > toSI x = x /~ unit_CGS (undefined :: Quantity (Dim l m t i Zero Zero Zero) a) > *~ unit_SI (undefined :: Quantity (Dim l m t i Zero Zero Zero) a) Again, the type signature is complex but deriving it is a mechanical process. = 'Show' instance = We round off by writing 'Show' instance for 'CGSDim' analogous to that of 'Dim'. Out of laziness we use the notation "sqrt(cm)" to represent halves of integral dimensions. Nothing is technically keeping us from doing a better job here. > instance forall lh mh t. > ( NumType lh > , NumType mh > , NumType t > ) => Show (CGSDim lh mh t) where > show _ = (Prelude.unwords Prelude.. catMaybes) > [ dimUnit "sqrt(cm)" (undefined :: lh) > , dimUnit "sqrt(g)" (undefined :: mh) > , dimUnit "s" (undefined :: t) > ] = Examples = Let us try the Coulomb attraction example from [2]. We start by performing the calculation in the SI. > q_si = 1.6021773e-19 *~ SI.coulomb -- Elementary charge in SI. > r_si = 0.1 *~ SI.nano SI.meter -- Distance in SI > f_si = q_si ^ pos2 / (_4 * pi * e0 * r_si ^ pos2) > where > e0 = 8.8541878e-12 *~ (SI.ampere * SI.second / (SI.volt * SI.meter)) The same calculation in the CGS system. > q_cgs = fromSI q_si -- Elementary charge in CGS. > r_cgs = fromSI r_si -- Distance in CGS > f_cgs = q_cgs ^ pos2 / r_cgs ^ pos2 Inspecting the values in GHCi shows us that the results are consistent (within reasonable accuracy) with [2]. *Buckwalter.Dimensional.CGS> f_si 2.3070794737101255e-8 m kg s^-2 *Buckwalter.Dimensional.CGS> f_cgs 2.30708078598602e-3 sqrt(cm)^2 sqrt(g)^2 s^-2 To convert from CGS to SI we must specify the type of the SI 'Quantity'. > f_si' = toSI f_cgs :: SIQ.Force Double *Buckwalter.Dimensional.CGS> f_si' 2.3070807859860202e-8 m kg s^-2 We follow up with another conversion example demonstrating the ambiguity in the conversion from CGS to SI. > c = 1 *~ SI.farad -- A SI capacitance. > c_cgs = fromSI c -- Capacitance has dimensionality L in CGS. > c' = toSI c_cgs :: SIQ.Capacitance Double > c'' = toSI c_cgs :: Length Double *Buckwalter.Dimensional.CGS> c 1.0 m^-2 kg^-1 s^4 A^2 *Buckwalter.Dimensional.CGS> c_cgs 8.98755691740885e11 sqrt(cm)^2 *Buckwalter.Dimensional.CGS> c' 1.0 m^-2 kg^-1 s^4 A^2 *Buckwalter.Dimensional.CGS> c'' 8.98755691740885e9 m = Future work = This is a very rudimentary implementation. To make it more practical a significant number of quantities and units, in particularly those commonly used with the CGS, would need to be added. In the mean time all units defined for the SI can be used with the CGS by applying 'fromSI' to quantities defined from the SI units. If anyone is willing to add quantities/units (or other enhancements) I will happily to accept patches. Personally I do not expect to use this module and therefore do not intend to invest much more time in it. If the module has other users I might reconsider. And of course, another direction of future work is to define additional systems (e.g. natural, relativistic) using this module as a template. I imagine this should be fairly straight forward. = References = [1] http://code.google.com/p/dimensional/wiki/ChuckBlake20070611 [2] http://www.tf.uni-kiel.de/matwis/amat/mw1_ge/kap_2/basics/b2_1_14.html ~~~~~~~~~~ END 'Buckwalter/Dimensional/CGS.lhs' ~~~~~~~~~~

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The Monad.Reader (8) - Extended Deadline
by Wouter Swierstra 02 Aug '07

02 Aug '07

Call for Copy The Monad.Reader - Issue 8 I would like to welcome articles for the next issue of The Monad.Reader. Due to a lack of submissions, I have extended the deadline for the next issue to ** September 1st, 2007 ** Please consider writing something for this issue to help The Monad.Reader over the summer! * The Monad.Reader * The Monad.Reader is an electronic magazine about all things Haskell. It is less formal than a journal, but somehow more enduring than a wiki-page. There have been a wide variety of articles including: puzzles, book reviews, code snippets, tutorials, and half-baked research ideas. * Submission Details * Get in touch with me if you intend to submit something -- the sooner you let me know what you're up to, the better. Please submit articles for the next issue by e-mail (wss at cs.nott.ac.uk) to me before September 1st, 2007. Articles should be written according to the guidelines available from: http://www.haskell.org/haskellwiki/The_Monad.Reader Please submit a .pdf of your article, together with your source files. The sources will be released together with the magazine under a BSD license. If you would like to submit an article, but have trouble with LaTeX please let me know and we'll sort something out. Looking forward to your submission, Wouter

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ANN: encoding-0.1 release
by Henning Günther 02 Aug '07

02 Aug '07

Dear fellow Haskellers, I'm proud to announce the release of "encoding", a Haskell library to cope with many character encodings found on modern computers. This (probably) bug-ridden release should mainly be used to critize it and to find out if it could be actually useful for anyone. At the moment it supports (much more is planned): ASCII (lame, I know) UTF-8, -16, -32 ISO 8859-* (alias latin-*) CP125* (windows codepages) KOI8-R Bootstring (base for punycode) You can find the darcs repository on [1] and a tarball on [2]. So please, send comments, bugs, suggestions and code! Henning [1] http://code.haskell.org/encoding/ [2] http://hackage.haskell.org/cgi-bin/hackage-scripts/package/encoding-0.1

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CFP: 3rd Int'l Workshop on Automated Specification and Verification of Web Systems (WWV'07)
by Demis 02 Aug '07

02 Aug '07

[ We apologize for multiple copies ] ******************************************************************* Preliminary Call For Papers 3rd International Workshop on Automated Specification and Verification of Web Systems (WWV'07) San Servolo island, Venice (Italy) December 14, 2007 http://wwv07.dimi.uniud.it/ ******************************************************************* 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 original papers 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 * Web quality and Web metrics * Web usability and accessibility * Testing and evaluation of Web systems and applications 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'07 will be held in December in the convention centre of the island of San Servolo, Venice, Italy. SUBMISSION PROCEDURE Submissions must be received by October 21, 2007. In addition, an ASCII version of the title and abstract must have been submitted by October 14, 2007. Submitted papers should be at most 15 pages in the Electronic Notes in Theoretical Computer Science (ENTCS) style, and should include an abstract and the author's information. See the author's instructions of ENTCS style at http://www.entcs.org. PUBLICATION Accepted papers will be published in a preliminary proceedings volume, which will be available during the workshop. Publication of the workshop post-proceedings in the Elsevier series Electronic Notes in Theoretical Computer Science (ENTCS) is envisaged. PROGRAM CO-CHAIRS Santiago Escobar (Technical University of Valencia, Spain) Massimo Marchiori (University of Padova, Italy) WORKSHOP CHAIR Demis Ballis (University of Udine, Italy) PROGRAM COMMITTEE (to be announced) IMPORTANT DATES Abstract Submission October 14, 2007 Full Paper Submission October 21, 2007 Acceptance Notification November 12, 2007 Camera Ready November 23, 2007 Workshop December 14, 2007 (temptative)

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