September 2008 - Haskell

WLPE'08 - Call for Papers, deadline extended to Sep 21st
by WLPE-08 10 Sep '08

10 Sep '08

WLPE'08 -- Call for Papers The 18th Workshop on Logic-based methods in Programming Environments http://www.clip.dia.fi.upm.es/Conferences/WLPE08/ December 9th-13th 2008, Udine, Italy (Satellite Workshop of ICLP 2008) The 18th Workshop on Logic-based methods in Programming Environments will take place in Udine (Italy), as a satellite workshop of ICLP 2008, the 24th International Conference on Logic Programming. This workshop will continue the series of successful international workshops on logic programming environments held in Ohio, USA (1989), Eilat, Israel (1990), Paris, France (1991), Washington D.C., USA (1992), Vancouver, Canada (1993), Santa Margherita Ligure, Italy (1994), Portland, USA (1995), Leuven, Belgium (1997), Las Cruces, USA (1999), Paphos, Cyprus (2001), Copenhagen, Denmark (2002), Mumbai, India (2003), Saint Malo, France (2004), Sitges (Barcelona), Spain (2005), Seattle, USA (2006) and Porto, Portugal (2007). More information about the series of WLPE workshops can be found at http://www.cs.usask.ca/projects/envlop/WLPE/ The workshop aims at providing an informal meeting for researchers working on logic-based methods and tools which support program development and analysis. This year, we plan to continue and consolidate the shift in focus from environmental tools for logic programming to logic-based environmental tools for programming in general, so that this workshop can be possibly interesting for a wider scientific community. In addition to papers describing more conceptual and theoretical work, the call for papers will solicit papers describing the implementation of, and the experience with, such tools. Areas particularly relevant to the workshop include (but are not limited to): - static and dynamic analysis - debugging and testing - program verification and validation - code generation from specifications - termination and non-termination analysis - reasoning on occurs-check freeness and determinacy - profiling and performance analysis - type- and mode analysis - module systems - optimization tools Authors who are interested in taking part in the workshop, but are unsure if their work falls within its scope, are invited to contact the organizers and will be given suitable advice. Workshop Organizers ------------------- Puri Arenas Facultad de Informatica Universidad Complutense de Madrid 28040-Madrid, Spain Email: puri(a)sip.ucm.es Phone: +34 91 394 76 33 Fax: +34 91 336 50 18 http://www.clip.dia.fi.upm.es/puri Damiano Zanardini Facultad de Informatica Universidad PolitÃÂ©cnica de Madrid 28660-Boadilla del Monte, Madrid, Spain Email: damiano(a)clip.dia.fi.upm.es Phone: +34 91 336 74 48 Fax: +34 91 394 75 29 http://www.clip.dia.fi.upm.es/damiano Program Committee ----------------- - Puri Arenas, Universidad Complutense de Madrid (ws co-chair) - Michael Codish, Ben-Gurion University of the Negev - Roberta Gori, Universita di Pisa - Arnaud Gotlieb, IRISA/CNRS UMR 6074 - Patricia Hill, University of Leeds - Jacob Howe, City University, London - Sabina Rossi, Universita Ca' Foscari di Venezia - Tom Schrijvers, K.U.Leuven - Alexander Serebrenik, Technische Universiteit Eindhoven - Wim Vanhoof, University of Namur - German Vidal, Universidad Politecnica de Valencia - Damiano Zanardini, Universidad Politecnica de Madrid,(ws co-chair) Important Dates --------------- Submission: September 21st (extended), 2008 (23:59:59 Samoa time (GMT -11)) Notification: October 8th, 2008 Camera-ready: October 26th, 2008 Workshop: December 12th, to be confirmed Submission ---------- Papers should be submitted to http://www.easychair.org/conferences/?conf=wlpe2008 The length of papers can range from 2 to 15 pages in LNCS style. Informal proceedings will be distributed at the workshop. After the workshop, proceedings will be available on-line in the Computing Research Repository (CoRR). In addition to papers describing conceptual and theoretical work, papers describing the implementation of and the experience with tools are welcome.

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Final CFP: Practical Aspects of Declarative Languages 2009
by Andy Gill 08 Sep '08

08 Sep '08

Hi, By popular demand, the deadline has been extended to the 11th. Please submit! Andy Gill ---------------------------------------------------------------------------------- CALL FOR PAPERS!!! Eleventh International Symposium on Practical Aspects of Declarative Languages 2009 (PADL '09) http://cs.utdallas.edu/padl09/ Savannah Georgia, USA January 19-20, 2009 Co-located with ACM POPL'09 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 raise 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 09 welcomes new ideas and approaches pertaining to applications and implementation of declarative languages. PADL 09 will be co-located with the ACM POPL. IMPORTANT DATES AND SUBMISSION GUIDELINES Paper Submission: September 11, 2008 Notification: October 10, 2008 Camera-ready: November 5, 2008 Symposium: January 19-20, 2009 Authors should submit an electronic copy of the full paper (written in English) in Postscript (Level 2) or PDF, in the Springer LNCS format (see http://www.springeronline.com/lncs/ ). In addition to the technical papers of previous PADL conferences, PADL 09 will contain a streamk for application papers. TECHNICAL PAPERS Technical papers must describe original, previously unpublished results, and must not be simultaneously submitted for publication elsewhere. Each submission must be written in English, and include three to four keywords, which will be used to assist us in selecting appropriate reviewers for the paper. Submissions must not exceed 15 pages in Springer LNCS format. APPLICATION PAPERS Application papers are a mechanism to present important practical applications of declarative languages that occur in industry or in areas of research other than computer science. Application papers will be published in the Springer-Verlag conference proceedings, and will be presented in a separate poster session. Application papers, are expected to describe complex and/or real-world applications that rely on an innovative use of declarative languages. Application descriptions, engineering solutions and real-world experiences (both positive and negative) are solicited. The limit for application papers is 3 pages in Springer LNCS format. MOST PRACTICAL PAPER AWARD The Most Practical Paper award will be given to the technical 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. PROGRAM COMMITTEE Lennart Augustsson Credit Suisse (UK) Hasan Davulcu Arizona State University (US) Inés Dutra Universidade do Porto (PT) John Gallagher Roskilde University (DK) Andy Gordon Microsoft Research (UK) Jeff Gray University of Alabama at Birmingham (US) Kevin Hamlen University of Texas at Dallas (US) Fergus Henderson Google (US) Gabriele Keller University of New South Wales (Australia) Michael Kifer SUNY Stony Brook (US) Ilkka Niemelä Helsinki University of Technology (FI) Johan Nordlander Luleå University of Technology (Sweden) Luís Pereira Universidade Nova de Lisboa (PT) Tom Schrijvers Katholieke Universiteit Leuven (BE) Lindsey Spratt Onology Works (US) Don Stewart Galois, Inc (US) Walter Wilson Systems Development and Analysis (US) Contacts: For information about papers and submissions, please contact a Program Chair: Andy Gill PC co-Chair - PADL 2009 Dept. of Electrical Engineering & Computer Science The University of Kansas 2001 Eaton Hall 1520 West 15th Street Lawrence, KS 66045-7621 Email: andygill <AT> ku.edu Terrance Swift PC co-Chair - PADL 2009 Centre for Artificial Intelligence (CENTRIA) Departamento de Informática, FCT/UNL Quinta da Torre 2829-516 CAPARICA - Portugal Email: tswift <AT> cs.sunysb.edu For other information about the conference, please contact: Kevin Hamlen General Chair - PADL 2009 Department of Computer Science University of Texas at Dallas Richardson, TX, USA Email: hamlen <AT> utdallas.edu

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Haskell Weekly News: Issue 84 - September 6, 2008
by Brent Yorgey 06 Sep '08

06 Sep '08

--------------------------------------------------------------------------- Haskell Weekly News http://sequence.complete.org/hwn/20080906 Issue 84 - September 06, 2008 --------------------------------------------------------------------------- Welcome to issue 84 of HWN, a newsletter covering developments in the [1]Haskell community. This is the "This issue is not late since the HWN will henceforth be published on Saturday now that I have real work to do" edition. Featured this week: darcs hacking sprint plans solidify, xmonad 0.8 released, typed sprintf and sscanf, and tons of discussion about everything from functional references to splitting up the base library to the future direction of Haskell. Announcements unicode-properties 3.2.0.0, unicode-names 3.2.0.0. Ashley Yakeley [2]announced the release of the [3]unicode-properties 3.2.0.0 and [4]unicode-names 3.2.0.0 packages, which are representations in Haskell of various data in the Unicode 3.2.0 Character Database. experimental static blog engine in Haskell. jinjing [5]announced the initial release of [6]Panda, an experimental static blog engine written in Haskell. darcs hacking sprint, venues confirmed! (25-26 October). Eric Y. Kow [7]announced that two venues (Brighton, UK and Portland, Oregon, USA) have been confirmed for the [8]darcs hacking sprint on 25-26 October. darcs weekly news #2. Eric Y. Kow The second weekly issue of the [9]darcs weekly news has been published. xmonad 0.8 released!. Don Stewart [10]announced the release of [11]xmonad 0.8, featuring a general purpose "gaps" replacement, locale support, the ability to create your own configuration parsers, and various other [12]enhancements and fixes. POPL logo design contest. Don Stewart [13]forwarded a message announcing a logo design contest for POPL 2009. Dust off your magic markers/photoshop skills and get designing! ICFP09 Announcement. Matthew Fluet [14]announced [15]ICFP 2009, to be held 31st August to 2nd September 2009 in Edinburgh. ICFP provides a forum for researchers and developers to hear about the latest work on the design, implementations, principles, and uses of functional programming. Fast parallel binary-trees for the shootout: Control.Parallel.Strategies FTW!. Don Stewart [16]announced that the Computer Language Shootout recently got a quad core 64 bit machine, and outlined a plan and some initial results for porting the Haskell entries to take advantage of the available parallelism. The initial view on typed sprintf and sscanf. oleg [17]announced an implementation of typed sprintf and sscanf functions sharing the same formatting specifications, which also led to some interesting discussion and alternative proposals. Discussion Generalize groupBy in a useful way?. Bart Massey [18]proposed changing the implementation of groupBy to extend its usefulness for predicates which are not equivalence relations. Splitting SYB from the base package in GHC 6.10. JosÃ© Pedro MagalhÃ£es [19]initiated a discussion regarding splitting the SYB libraries out of the base package for GHC 6.10. The base library and GHC 6.10. Ian Lynagh initiated a [20]discussion on further splitting up the base package for GHC 6.10. Functional references. Tim Newsham began a [21]discussion on functional references and the possibility of merging the existing four or five implementations into something more standard. Types and Trees. Matt Morrow [22]wrote something about types and type representations, involving some commutative diagrams and some code. I haven't read it yet but it looks neat! Research language vs. professional language. Ryan Ingram started an interesting [23]discussion on the future direction(s) of the Haskell language. language proposal: ad-hoc overloading. Ryan Ingram [24]proposed adding ad-hoc name overloading to Haskell, prompting quite a bit of discussion. Top Level <-. Ashley Yakeley originally [25]asked whether there is any interest in implementing a top level "<-" to run monadic code. This set off a cascade of discussion the likes of which have been rarely seen on the Cafe. I would tell you what the discussion has been about but I must confess that I haven't read it. Blog noise [26]Haskell news from the [27]blogosphere. * Eric Kow (kowey): [28]darcs hacking sprint (25-26 October 2008). * Magnus Therning: [29]Confusion with HaskellDB. * Xmonad: [30]xmonad 0.8 released!. * Real-World Haskell: [31]Speaking in Silicon Valley next week. * Luke Palmer: [32]Composable Input for Fruit. * Luke Palmer: [33]Slicing open the belly of the IO monad in an alternate universe. * "FP Lunch": [34]Modular Monad Transformers. * Douglas M. Auclair (geophf): [35]Fuzzy unification parser in Haskell. * Bjoern Edstroem: [36]Speeding up Haskell with C -- a very short introduction. * Eric Kow (kowey): [37]darcs weekly news #2. * Roman Cheplyaka: [38]Physics and polyhedra. * Well-Typed.Com: [39]The new haskell.org community SPARC server is online. * Douglas M. Auclair (geophf): [40]A stream of primes as Comonad. * Eric Kidd: [41]Ubiquitous Hoogle. Eric shows how to integrate a [42]Hoogle search command into [43]Ubiquity. * Dan Piponi (sigfpe): [44]Untangling with Continued Fractions: Part 3. The vector space monad and rational tangles. Quotes of the Week * dons: maybe we should do a "recommend RWH to a java programmer" campaign :) * gwern: we fill fight them in the registers, we will fight them in the caches; we shall fight them in the core, and even in the backing store. And we shall never surrender! About the Haskell Weekly News New editions are posted to [45]the Haskell mailing list as well as to [46]the Haskell Sequence and [47]Planet Haskell. [48]RSS is also available, and headlines appear on [49]haskell.org. To help create new editions of this newsletter, please see the information on [50]how to contribute. Send stories to byorgey at cis dot upenn dot edu. The darcs repository is available at darcs get [51]http://code.haskell.org/~byorgey/code/hwn/ . References 1. http://haskell.org/ 2. http://article.gmane.org/gmane.comp.lang.haskell.libraries/9973 3. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/unicode-properti… 4. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/unicode-names 5. http://article.gmane.org/gmane.comp.lang.haskell.cafe/44181 6. http://jinjing.blog.easymic.com/ 7. http://article.gmane.org/gmane.comp.lang.haskell.cafe/44164 8. http://wiki.darcs.net/index.html/Sprints 9. http://code.haskell.org/darcs/darcs-news 10. http://article.gmane.org/gmane.comp.lang.haskell.cafe/44157 11. http://xmonad.org/ 12. http://haskell.org/haskellwiki/Xmonad/Notable_changes_since_0.7 13. http://article.gmane.org/gmane.comp.lang.haskell.cafe/44069 14. http://article.gmane.org/gmane.comp.lang.haskell.general/16413 15. http://www.cs.nott.ac.uk/~gmh/icfp09.html 16. http://article.gmane.org/gmane.comp.lang.haskell.cafe/43968 17. http://article.gmane.org/gmane.comp.lang.haskell.general/16405 18. http://thread.gmane.org/gmane.comp.lang.haskell.libraries/10016 19. http://thread.gmane.org/gmane.comp.lang.haskell.libraries/9962 20. http://thread.gmane.org/gmane.comp.lang.haskell.libraries/9929 21. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/44098 22. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/44028 23. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/43933 24. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/43897 25. http://thread.gmane.org/gmane.comp.lang.haskell.general/16393 26. http://planet.haskell.org/ 27. http://haskell.org/haskellwiki/Blog_articles 28. http://koweycode.blogspot.com/2008/09/darcs-hacking-sprint-25-26-october-20… 29. http://therning.org/magnus/archives/375 30. http://xmonad.wordpress.com/2008/09/05/xmonad-08-released/ 31. http://www.realworldhaskell.org/blog/2008/09/05/speaking-in-silicon-valley-… 32. http://luqui.org/blog/archives/2008/08/09/composable-input-for-fruit/ 33. http://luqui.org/blog/archives/2008/08/14/slicing-open-the-belly-of-the-io-… 34. http://sneezy.cs.nott.ac.uk/fplunch/weblog/?p=111 35. http://logicaltypes.blogspot.com/2008/09/fuzzy-unification-parser-in-haskel… 36. http://blog.bjrn.se/2008/09/speeding-up-haskell-with-c-very-short.html 37. http://koweycode.blogspot.com/2008/09/darcs-weekly-news-2.html 38. http://physics-dph.blogspot.com/2008/08/physics-and-polyhedra.html 39. http://blog.well-typed.com/2008/09/the-new-haskellorg-community-sparc-serve… 40. http://logicaltypes.blogspot.com/2008/09/stream-of-primes-as-comonad.html 41. http://www.randomhacks.net/articles/2008/09/01/ubiquitous-hoogle 42. http://www.haskell.org/hoogle/ 43. https://wiki.mozilla.org/Labs/Ubiquity 44. http://sigfpe.blogspot.com/2008/08/untangling-with-continued-fractions_31.h… 45. http://www.haskell.org/mailman/listinfo/haskell 46. http://sequence.complete.org/ 47. http://planet.haskell.org/ 48. http://sequence.complete.org/node/feed 49. http://haskell.org/ 50. http://haskell.org/haskellwiki/HWN 51. http://code.haskell.org/~byorgey/code/hwn/

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ICFP09 Announcement
by Matthew Fluet (ICFP Publicity Chair) 02 Sep '08

02 Sep '08

+--------------------------------------------------------------------+ ANNOUNCEMENT The 14th ACM SIGPLAN International Conference on Functional Programming ICFP 2009 31st August - 2nd September 2009 Edinburgh, United Kingdom ICFP provides a forum for researchers and developers to hear about the latest work on the design, implementations, principles, and uses of functional programming. ICFP 2009 will be held in Scotland's historic capital city of Edinburgh, during the final week of the Edinburgh International Festival. Further information is available from: http://www.cs.nott.ac.uk/~gmh/icfp09.html Graham Hutton General Chair, ICFP 2009 +--------------------------------------------------------------------+ | Dr Graham Hutton Email : gmh(a)cs.nott.ac.uk | | Functional Programming Lab | | School of Computer Science Web : www.cs.nott.ac.uk/~gmh | | University of Nottingham | | Jubilee Campus, Wollaton Road Phone : +44 (0)115 951 4220 | | Nottingham NG8 1BB, UK | +--------------------------------------------------------------------+

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REMINDER: OpenSPARC project application deadline this Friday
by Duncan Coutts 02 Sep '08

02 Sep '08

http://haskell.org/opensparc/ The deadline for applications for the Haskell OpenSPARC project is rapidly approaching. Applications have to be sent to: opensparc(a)community.haskell.org by the end of this week, Friday the 5th September. If you want any comments on your application before you submit it then contact me directly. Duncan (project coordinator) In other news, the server that Sun Microsystems donated to the community has just gone online at Chalmers: http://blog.well-typed.com/2008/09/the-new-haskellorg-community-sparc-serve…

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WLPE'08 - Call for Papers
by WLPE-08 02 Sep '08

02 Sep '08

WLPE'08 -- Call for Papers The 18th Workshop on Logic-based methods in Programming Environments http://www.clip.dia.fi.upm.es/Conferences/WLPE08/ December 9th-13th 2008, Udine, Italy (Satellite Workshop of ICLP 2008) The 18th Workshop on Logic-based methods in Programming Environments will take place in Udine (Italy), as a satellite workshop of ICLP 2008, the 24th International Conference on Logic Programming. This workshop will continue the series of successful international workshops on logic programming environments held in Ohio, USA (1989), Eilat, Israel (1990), Paris, France (1991), Washington D.C., USA (1992), Vancouver, Canada (1993), Santa Margherita Ligure, Italy (1994), Portland, USA (1995), Leuven, Belgium (1997), Las Cruces, USA (1999), Paphos, Cyprus (2001), Copenhagen, Denmark (2002), Mumbai, India (2003), Saint Malo, France (2004), Sitges (Barcelona), Spain (2005), Seattle, USA (2006) and Porto, Portugal (2007). More information about the series of WLPE workshops can be found at http://www.cs.usask.ca/projects/envlop/WLPE/ The workshop aims at providing an informal meeting for researchers working on logic-based methods and tools which support program development and analysis. This year, we plan to continue and consolidate the shift in focus from environmental tools for logic programming to logic-based environmental tools for programming in general, so that this workshop can be possibly interesting for a wider scientific community. In addition to papers describing more conceptual and theoretical work, the call for papers will solicit papers describing the implementation of, and the experience with, such tools. Areas particularly relevant to the workshop include (but are not limited to): - static and dynamic analysis - debugging and testing - program verification and validation - code generation from specifications - termination and non-termination analysis - reasoning on occurs-check freeness and determinacy - profiling and performance analysis - type- and mode analysis - module systems - optimization tools Authors who are interested in taking part in the workshop, but are unsure if their work falls within its scope, are invited to contact the organizers and will be given suitable advice. Workshop Organizers ------------------- Puri Arenas Facultad de Informatica Universidad Complutense de Madrid 28040-Madrid, Spain Email: puri(a)sip.ucm.es Phone: +34 91 394 76 33 Fax: +34 91 336 50 18 http://www.clip.dia.fi.upm.es/puri Damiano Zanardini Facultad de Informatica Universidad PolitÃÂ©cnica de Madrid 28660-Boadilla del Monte, Madrid, Spain Email: damiano(a)clip.dia.fi.upm.es Phone: +34 91 336 74 48 Fax: +34 91 394 75 29 http://www.clip.dia.fi.upm.es/damiano Program Committee ----------------- - Puri Arenas, Universidad Complutense de Madrid (ws co-chair) - Michael Codish, Ben-Gurion University of the Negev - Roberta Gori, Universita di Pisa - Arnaud Gotlieb, IRISA/CNRS UMR 6074 - Patricia Hill, University of Leeds - Jacob Howe, City University, London - Sabina Rossi, Universita Ca' Foscari di Venezia - Tom Schrijvers, K.U.Leuven - Alexander Serebrenik, Technische Universiteit Eindhoven - Wim Vanhoof, University of Namur - German Vidal, Universidad Politecnica de Valencia - Damiano Zanardini, Universidad Politecnica de Madrid,(ws co-chair) Important Dates --------------- Submission: September 15th, 2008 (23:59:59 Samoa time (GMT -11)) Notification: October 8th, 2008 Camera-ready: October 26th, 2008 Workshop: December 12nd, to be confirmed Submission ---------- Papers should be submitted to http://www.easychair.org/conferences/?conf=wlpe2008 The length of papers can range from 2 to 15 pages in LNCS style. Informal proceedings will be distributed at the workshop. After the workshop, proceedings will be available on-line in the Computing Research Repository (CoRR). In addition to papers describing conceptual and theoretical work, papers describing the implementation of and the experience with tools are welcome.

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BYTECODE09: 1st Call for Papers
by Samir Genaim 02 Sep '08

02 Sep '08

******************************************************** * 1st Call for Papers * * * * Fourth Workshop on Bytecode Semantics, * * Verification, Analysis and Transformation * * * * York, UK, 29th March 2009, part of ETAPS 2009 * * * * Venue: The University of York * * * * http://www.clip.dia.fi.upm.es/Conferences/BYTECODE09 * * * ******************************************************** Important Dates =============== Paper Submission December 21, 2008 Notification January 25, 2009 Final Version February 8, 2009 Workshop March 29, 2009 Workshop Description ==================== Bytecode, such as produced by e.g. .Net and Java compilers, has become an important topic of interest, both for industry and academia. The industrial interest stems from the fact that bytecode is typically used for the Internet and mobile devices (smartcards, phones, etc.), where security is a major issue. Moreover, bytecode is device-independent and allows dynamic loading of classes, which provides an extra challenge for the application of formal methods. In addition, the lack of structure of the code and the pervasive presence of the operand stack also provide extra challenges for the analysis of bytecode. This workshop will focus on the latest developments in the semantics, verification, analysis, and transformation of bytecode. Both new theoretical results and tool demonstrations are welcome. Invited Speaker =============== TBA Submission ========== There are two paper categories, Regular and Tool demo papers. Paper should be written using the ENTCS style and submitted through the easy chair page "http://www.easychair.org/conferences/?conf=bytecode08". Please indicate in the submission page the category of your submission. Submissions will be evaluated by the Program Committee for inclusion in the ENTCS proceedings. Regular research papers should be at most 15 pages (including bibliography and excluding well-marked appendices not intended for publication). They must contain original contributions, be written in English and be unpublished and not submitted simultaneously for publication elsewhere. Tool demo papers must describe a completed, robust and well-documented tool -- highlighting the overall functionality of the tool, the interfaces of the tool, interesting examples and applications of the tool, an assessment of the tool's strengths and weaknesses, and a summary of documentation/support available with the tool. The body of the paper must be no longer than 6 pages in length (including bibliography), and it should give an overview of the tool, the methodology associated with its use, a summary of how the tool has been applied and to what effect, and it should indicate what supporting artifacts (user manual, example repository, downloads, etc) are available. This material will be included in the ENTCS proceedings if the paper is accepted. In addition, the paper should include an appendix (limited to six pages) that gives an outline of the proposed demo presentation (this material will NOT appear in the ENTCS proceedings). Program Committee ================= Wolfgang Ahrendt Chalmers University of Technology, SWE Elvira Albert (co-chair) Complutense University of Madrid, ESP June Andronick Security Lab - Gemalto, FRA David Aspinall University of Edinburgh, UK Cristina Cifuentes Sun Microsystems, AUS Samir Genaim (co-chair) Technical University of Madrid, ESP Sara Kalvala The University of Warwick, UK Gerwin Klein The University of New South Wales, AUS Francesco Logozzo Microsoft Research, USA David Pichardie INRIA Rennes (IRISA), FRA Tamara Rezk INRIA-Microsoft, FRA Fausto Spoto University of Verona, ITA Eran Yahav IBM T.J. Watson Research Center, USA

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The final view on typed sprintf and sscanf
by oleg＠okmij.org 02 Sep '08

02 Sep '08

It would be remiss not to mention the dual solution to the problem of typed sprintf and sscanf sharing the same formatting specification. The previous message defined the embedded domain-specific language of formatting specifications in the initial style, as a data type. The language can also be defined in the final style. To the end user, the difference is hardly noticeable: all the tests of the previous message work as they are (modulo a few adjustments caused by the monomorphism restriction). However, whereas the initial style required GADT, the final solution is entirely in Haskell98. One often hears that hardly anything interesting can be written in Haskell98. I submit that implementing type-indexed terms, thought to require GADTs or similar dependent-type-like extensions, ought to count as interesting. Again, the formulation of the problem and the end-user interface remain exactly the same as described in the previous message. Here are a few examples: > tp1 = sprintf $ lit "Hello world" > -- "Hello world" > ts1 = sscanf "Hello world" (lit "Hello world") () > -- Just () > tp2 = sprintf (lit "Hello " ^ lit "world" ^ char) '!' > -- "Hello world!" > ts2 = sscanf "Hello world!" (lit "Hello " ^ lit "world" ^ char) id > -- Just '!' > fmt3 () = lit "The value of " ^ char ^ lit " is " ^ int > tp3 = sprintf (fmt3 ()) 'x' 3 > -- "The value of x is 3" > ts3 = sscanf "The value of x is 3" (fmt3 ()) (\c i -> (c,i)) > -- Just ('x',3) The only difference is the dummy unit argument to the fmt3 term, to keep it polymorphic and away from the monomorphism restrictions. Otherwise, the examples look the same and work the same. The complete code is available at http://okmij.org/ftp/Haskell/PrintScanF.hs It is Haskell98 and should work on any Haskell98 system (tested on GHC 6.8.2 and Hugs September 2006). Whereas the initial version defined the formatting language with the help of GADT, the final version uses a simple, single-parameter type class > class FormattingSpec repr where > lit :: String -> repr a a > int :: repr a (Int -> a) > char :: repr a (Char -> a) > (^) :: repr b c -> repr a b -> repr a c > infixl 5 ^ The printer and the scanner are two interpreters of the language > newtype FPr a b = FPr ((String -> a) -> b) > instance FormattingSpec FPr where > lit str = FPr $ \k -> k str > char = FPr $ \k -> \x -> k [x] > (FPr a) ^ (FPr b) = FPr $ \k -> a (\sa -> b (\sb -> k (sa ++ sb))) > newtype FSc a b = FSc (String -> b -> Maybe (a,String)) > instance FormattingSpec FSc where > lit str = FSc $ \inp x -> > maybe Nothing (\inp' -> Just (x,inp')) $ prefix str inp > char = FSc $ \inp f -> case inp of > (c:inp) -> Just (f c,inp) > "" -> Nothing > (FSc a) ^ (FSc b) = FSc $ \inp f -> > maybe Nothing (\(vb,inp') -> b inp' vb) $ a inp f > sprintf :: FPr String b -> b > sprintf (FPr fmt) = fmt id > sscanf :: String -> FSc a b -> b -> Maybe a > sscanf inp (FSc fmt) f = maybe Nothing (Just . fst) $ fmt inp f The transformation from the initial to the final style follows the correspondence described in http://okmij.org/ftp/Computation/tagless-typed.html#in-fin In fact, PrintScanF.hs was `derived' from PrintScan.hs by Emacs `code movements'. Once the syntax errors have been fixed, the code worked on the first try. One can easily define a yet another interpreter, to convert the formatting specification to a C-like format string.

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Linking Multiple Versions of the Same Package
by Ashley Yakeley 01 Sep '08

01 Sep '08

I tried doing this out of curiosity. Package B links to version 0.1 of open-witness, while package C links to B and version 0.1.1 of open-witness. Cabal stopped me when doing "cabal configure" in C: $ cabal configure Configuring C-0.1... Warning: This package indirectly depends on multiple versions of the same package. This is highly likely to cause a compile failure. package B-0.1 requires open-witness-0.1 package C-0.1 requires open-witness-0.1.1 It appears the issue is that package versions are not recorded in External Core names. Thus

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The initial view on typed sprintf and sscanf
by oleg＠okmij.org 01 Sep '08

01 Sep '08

We demonstrate typed sprintf and typed sscanf sharing the same formatting specification. Our solution is surprisingly trivial: it defines a simple embedded domain-specific language of formatting patterns. The functions sprintf and sscanf are two interpreters of the language, to build or parse a string according to the given pattern. Our solution relies only on GADTs. We demonstrate that lambda-abstractions at the type level are expressible already in the Hindley-Milner type system; GADT with the included polymorphic recursion help us use the abstractions. The typed sprintf takes the formatting specification and several arguments and returns the formatted string. The types and the number of arguments depend on the formatting specification. Conversely, the typed sscanf parses a string according to the formatting specification, passing parsed data to a consumer function. Again, the number and the types of the arguments to the consumer depend on the formatting specification. The typed sprintf problem has been investigated extensively: the first solution was shown by Danvy; more solutions were proposed by Hinze and Asai. The typed scanf problem received significantly less attention, if any. It seems that the implementation of the typed sprintf and sscanf sharing the same formatting specification has not been known. Here are a few examples of the typed sprintf and sscanf > tp1 = sprintf $ lit "Hello world" > -- "Hello world" > ts1 = sscanf "Hello world" (lit "Hello world") () > -- Just () > tp2 = sprintf (lit "Hello " ^ lit "world" ^ char) '!' > -- "Hello world!" > ts2 = sscanf "Hello world!" (lit "Hello " ^ lit "world" ^ char) id > -- Just '!' > fmt3 = lit "The value of " ^ char ^ lit " is " ^ int > tp3 = sprintf fmt3 'x' 3 > -- "The value of x is 3" > ts3 = sscanf "The value of x is 3" fmt3 (\c i -> (c,i)) > -- Just ('x',3) A formatting specification is built by connecting primitive specifications (such as lit "string", int, char) with (^). We observe that whereas sprintf $ lit "Hello world" has the type String, sprintf $ lit "The value of " ^ char ^ lit " is " ^ int has the type Char -> Int -> String. Likewise, the type of the consumer of the values parsed by sscanf varies with the formatting specification. The example of tp3 and ts3 demonstrates that sprintf and sscanf can indeed use exactly the same formatting specification, which is a first-class value. Printf and scanf are present in many languages (e.g., C and Haskell); in most of the cases, they are not type-safe: the type checker does not stop the programmer from passing to printf more or fewer arguments than required by the formatting string. OCaml supports typed sprintf and sscanf, which relies on a particular weird typing of these functions, resulting in formatting specifications being not first class. Our sscanf has exactly the same interface as that in OCaml, modulo weird typing. The complete code of the typed sprintf and sscanf with more examples is available at http://okmij.org/ftp/Haskell/PrintScan.hs It can be used in Haskell programs as it is; it is trivial to arrange it in a Haskell library or Hackage package. Our implementation is based on the observation of Hinze (Ralf Hinze. Functional Pearl: Formatting: a class act. JFP, 13(5):935-944, September 2003) that the formatting specification is a `type transformer', a functor. For example, the formatting specification 'int' is associated with a functor transforming a type 't' to a type 'Int -> t'. Hinze represented functors in Curry style; the functor associated with 'int' is then (Int ->). However, a more direct, Church-style representation is also possible. Let us consider a type "F a b" where "F" is a binary type constructor, "a" is a type variable, and "b" is a type that may include one or more occurrences of "a". That type is essentially a type abstraction, the type-level lambda-function. To apply the function to an argument, we unify "a" with the argument; the second parameter of "F" is the result of the application. This is the standard emulation of lambda-calculus in Prolog. Based on this observation, we define the language of formatting specifications as follows: > data F a b where > FLit :: String -> F a a > FInt :: F a (Int -> a) > FChr :: F a (Char -> a) > (:^) :: F b c -> F a b -> F a c > (^) = (:^) > lit = FLit > int = FInt The type of (:^) expresses the inverse functional composition of two type-level lambdas; one may read "F" as `big lambda'. The formatting specification can be interpreted in two different ways, for printing and for parsing. The types of the interpreters are pleasingly symmetric: > intp :: F a b -> (String -> a) -> b > intp (FLit str) k = k str > intp FChr k = \x -> k [x] > intp (a :^ b) k = intp a (\sa -> intp b (\sb -> k (sa ++ sb))) > ints :: F a b -> String -> b -> Maybe (a,String) > ints (FLit str) inp x = maybe Nothing (\inp' -> Just (x,inp')) $ > prefix str inp > ints FChr (c:inp) f = Just (f c,inp) > ints FChr "" f = Nothing > ints (a :^ b) inp f = maybe Nothing (\(vb,inp') -> ints b inp' vb) $ > ints a inp f The printing interpretation implements Asai's accumulator-less alternative to Danvy's functional unparsing: http://pllab.is.ocha.ac.jp/~asai/papers/tr07-1.ps.gz The printing interpretation of (a :^ b) is string concatenation in CPS form. The sprintf and sscanf are then simple wrappers: > sprintf :: F String b -> b > sprintf fmt = intp fmt id > sscanf :: String -> F a b -> b -> Maybe a > sscanf inp fmt f = maybe Nothing (Just . fst) $ ints fmt inp f The problem of the typed printf and scanf over the same formatting specification has been posed by Chung-chieh Shan in a discussion with Kenichi Asai and Yukiyoshi Kameyama. I'm grateful to them for inspiration.

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