May 2004 - Haskell - Haskell.org

[Haskell] UNIF'04 workshop @ IJCAR 2004: Deadline extension until 21/5
by Ralf Treinen 14 May '04

14 May '04

Call for Papers/Abstracts/System descriptions ***** Deadline extentended until Friday, Mai 21 ******* UNIF 2004 18th International Workshop on Unification July 4-5, 2004, Cork, Ireland Affiliated with IJCAR'04 http://www.faculty.iu-bremen.de/mkohlhase/event/unif04/ UNIF is the main international meeting on unification. Unification is concerned with the problem of identifying given terms, either syntactically or modulo a given logical theory. Syntactic unification is the basic operation of most automated reasoning systems, and unification modulo theories can be used, for instance, to build in special equational theories into theorem provers. The aim of UNIF 2004, as that of the previous meetings, is to to bring together people interested in unification, present recent (even unfinished) work, and discuss new ideas and trends in unification and related fields. In particular, it is intended to offer a good opportunity for young researches and researchers working in related areas to get an overview of the current state of the art in unification theory and get in contact with the experts in the field. ---------------------------------------------------------------------- TOPICS OF INTEREST ---------------------------------------------------------------------- A non-exclusive list of topics of interest is: * Unification * E-unification * Unification Algorithms * Higher-Order Unification * String Unification * Context Unification * Combination problems * Disunification * Typed Unification * Related Topics * Constraint Solving * Tree Descriptions * Matching * Narrowing * Applications * Type Checking and Type Inference * Automated Deduction * Rewriting * Functional and Logic Programming * Grammars * Computational Linguistics * Implementations ---------------------------------------------------------------------- INVITED SPEAKERS ---------------------------------------------------------------------- There will be two invited speakers. ---------------------------------------------------------------------- IMPORTANT DATES ---------------------------------------------------------------------- NEW: Deadline for electronic submission: Friday, May 21, 2004 Email: unif04(a)iu-bremen.de Notification of acceptance: Monday, May 24, 2004 Deadline for camera-ready papers: Monday, June 7, 2004 Workshop: July 4 - 5, 2004 ---------------------------------------------------------------------- SUBMISSION DETAILS ---------------------------------------------------------------------- Authors are invited to submit via email an abstract (1-5 pages), a paper (no longer than 15 pages), or a system description (no more than 5 pages) in Postscript or PDF format to: unif04(a)iu-bremen.de before May 21, 2004. Authors are encouraged to use LaTeX2e and the Springer llncs class. ---------------------------------------------------------------------- PUBLICATION ---------------------------------------------------------------------- Accepted papers, abstracts and system descriptions will be included in the proceedings which will be available at the workshop. ---------------------------------------------------------------------- ORGANIZING COMMITTEE ---------------------------------------------------------------------- Michael Kohlhase (International University Bremen, Germany) Hitoschi Ohsaki (National Institute of Advanced Industrial Science and Technology, Amagasaki, Japan) Steve Prestwich (Universtity College, Cork, Ireland) Ralf Treinen (Ecole Normale Superieure, Cachan, France) Manfred Schmidt-Schauss (Johann Wolfgang Goethe-Universit"at Frankfurt am Main, Germany) -- Ralf Treinen Laboratoire Spécification et Vérification CNRS & École Normale Supérieure de Cachan http://www.lsv.ens-cachan.fr/~treinen

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[bctcs05-info] BCTCS 2005 Announcement
by Graham Hutton 13 May '04

13 May '04

+--------------------------------------------------------------------+ ANNOUNCEMENT 21st British Colloquium for Theoretical Computer Science BCTCS 2005 22-24 March 2005 University of Nottingham, UK The purpose of BCTCS is to provide a forum for researchers in theoretical computer science to meet, present research findings, and discuss developments in the field. It also aims to provide an environment for PhD students to gain experience in presenting their work, and benefit from contact with established researchers. SCOPE The scope includes all aspects of theoretical computer science, such as algorithms, complexity, semantics, formal methods, concurrency, types, languages and logics. Computer scientists, mathematicians and researchers from outside of the UK are all welcome to attend. PROGRAMME The programme will consist of 2.5 days of invited talks, tutorials, and contributed talks. The invited speakers are as follows: Alan Gibbons - King's College London Andrew Gordon - Microsoft Research, Cambridge Ralf Hinze - University of Bonn Conor McBride - University of Durham Rajeev Raman - University of Leicester LOCATION The colloquium will be held on the Jubilee Campus of the University of Nottingham, which has won many awards for its design and environmental features. Nottingham is centrally located in the UK, and is easily reachable by car, train and plane (Nottingham East Midlands Airport.) REGISTRATION The deadline for registration and submission of proposed talks is 7 February 2005. The registration fee will be approximately 275 UK pounds, including accommodation and all meals. Twenty funded places for UK-based PhD students are in the process of being sought. FURTHER DETAILS Google search - BCTCS 2005 Web page - http://www.cs.nott.ac.uk/~gmh/bctcs05.html +--------------------------------------------------------------------+ _______________________________________________ bctcs05-info mailing list bctcs05-info(a)cs.nott.ac.uk http://www.cs.nott.ac.uk/mailman/listinfo/bctcs05-info This message has been scanned but we cannot guarantee that it and any attachments are free from viruses or other damaging content: you are advised to perform your own checks. Email communications with the University of Nottingham may be monitored as permitted by UK legislation.

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[Haskell] generic currying (type classes and functional dependencies)
by Duncan Coutts 13 May '04

13 May '04

Hi All, I'm trying to write a generic curry (& uncurry) function that works for functions of any arity. I have a couple solutions that nearly work, both involving type classes. Here's the first one: class Curry tupled curried where genericCurry :: tupled -> curried genericUncurry :: curried -> tupled The base case is obvious: instance Curry ((a,b) -> c) (a -> b -> c) where genericCurry f x y = f (x,y) genericUncurry f' (x,y) = f' x y However, the inductive case is more tricky. We cannot generically create tuples of arbitrary size so we'll have to make do with left (or right) nested pairs. This nesting leads to problems later and for starters requires overlapping instances: instance Curry ( (b,c) -> d) ( b -> c -> d) => Curry ((a,(b,c)) -> d) (a -> b -> c -> d) where genericCurry f a b c = f (a,(b,c)) genericUncurry f (a,(b,c)) = f a b c This works, but when we come to use it we often run into cases where the type checker complains with messages such as: No instance for (Curry ((Int, Int) -> Int) (a -> b -> Int)) I guess that this is because it fails to be able to convince itself that a & b are Int, in which case there would be an instance. This can be solved by supplying enough type annotations, however this is annoying and part of the point of a generic curry is that we don't know the arity of the function to which we are applying it. So I thought that functional dependencies might help because the curried type should uniquely determine the uncurried type (and vice versa). However if I change the class declaration to: class Curry tupled curried | tupled -> curried, curried -> tupled where genericCurry :: tupled -> curried genericUncurry :: curried -> tupled Then the compiler complains about my instance declarations: Functional dependencies conflict between instance declarations: ./Curry.hs:11:0: instance Curry ((a, b) -> c) (a -> b -> c) ./Curry.hs:16:0: instance (Curry ((b, c) -> d) (b -> c -> d)) => Curry ((a, (b, c)) -> d) (a -> b -> c -> d) I don't fully understand why this is the case, but it is to do with the nested pairing, because individual instance declarations for 3-tuples, 4-tuples work find. Any insight or suggestions would be interesting. Duncan

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LOPSTR'04 final call for extended abstracts
by Sandro Etalle 12 May '04

12 May '04

LOPSTR 2004 Verona, Italy, August 26-28, 2004 http://www.sci.univr.it/~lopstr04 FINAL CALL FOR EXTENDED ABSTRACTS DEADLINE (EXTENDED, FIRM): May 17, 2004 The aim of the LOPSTR series is to stimulate and promote international research and collaboration on logic-based program development, and the workshop is open to contributions in logic-based program development in any language paradigm. Starting this year, LOPSTR will put extra emphasis to the field of verification; in fact LOPSTR will also incorporate the VCL (verification in computational logic) workshop series. LOPSTR'04 will be held at the University of Verona http://www.univr.it co-located with SAS 2004 http://www.sci.univr.it/~sas04, the International Static Analysis Symposium, PEPM 2004 http://www.sci.univr.it/~pepm04 - ACM SIGPLAN 2004 Workshop on Partial Evaluation and Semantics Based Program Manipulation, and PPDP 2004 http://www.sci.univr.it/~ppdp04 - 6th ACM-SIGPLAN International Conference on Principles and Practice of Declarative Programming. Past workshops were held in Manchester, UK (1991, 1992, 1998), Louvain-la-Neuve, Belgium (1993), Pisa, Italy (1994), Arnhem, the Netherlands (1995), Stockholm, Sweden (1996), Leuven, Belgium (1997), Venice, Italy (1999), London, UK (2000), Paphos, Cyprus (2001), Madrid, Spain (2002), Uppsala, Sweden (2003). Since 1994 the proceedings have been published in the LNCS series of Springer-Verlag. LOPSTR also aims to be a lively, friendly forum for presenting and discussing work in progress, so it is a real workshop in the sense that it is also intended to provide useful feedback to authors on their preliminary research. Formal proceedings of the workshop are produced only after the workshop, so that authors can incorporate this feedback in the published papers. Scope of the Workshop We solicit extended abstracts and full papers (DEADLINE FOR FULL PAPER HAS PASSED). Topics of interest cover all aspects of logic-based program development, all stages of the software life cycle, and issues of both programming-in-the-small and programming-in-the-large. The following is a non-exhaustive list of topics: * specification * synthesis * verification * transformation * specialisation * analysis * optimisation * composition * reuse * applications and tools * proofs as programs * component-based software development * agent-based software development * software architectures * design patterns and frameworks * program refinement and logics for refinement Submission Guidelines Authors can either submit extended abstracts (short papers) describing work in progress or they can choose to submit full papers (DEADLINE FOR FULL PAPER HAS PASSED). Contributions should be written in English and should be submitted electronically in Postscript or PDF format at http://profs.sci.univr.it/~lopstr04/index.html. Authors are also asked to send the title and abstract of their submission three days before the deadline to lopstr04(a)sci.univr.it. Prospective authors who have difficulties for the electronic submission may contact the chairman at lopstr04(a)sci.univr.it. Extended abstracts should not exceed 6 pages in llncs format and may describe work in progress. Promising abstracts relevant to the scope of LOPSTR will be selected for presentation at the workshop. The submission deadline for extended abstract is May 17, 2004 (extended, strict). Full papers ... deadline for full papers has passed. Accepted papers and abstracts will be collected in informal pre-proceedings which will be available at the workshop. After the workshop, authors of extended abstract which are judged mature for publication will be invited to submit full papers. These will be reviewed according to the usual refereeing procedures, and accepted papers will be published in the final collection of papers (together with the accepted full papers) which is expected to be published in the Lecture Notes in Computer Science series by Springer-Verlag. All the full papers accepted before the workshop will automatically appear in that book as well; there will be no additional refereeing (although authors will be given a chance to revise their paper, if they so wish, based upon the feedback from the LOPSTR event). Program Committee * Gilles Barthe (France) * Annalisa Bossi (Italy) * Maurice Bruynooghe (Belgium) * Francisco Bueno (Spain) * Giorgio Delzanno (Italy) * Tom Ellman (USA) * Sandro Etalle (The Netherlands) program chair * Norbert Fuchs (Switzerland) * Gopal Gupta (USA) * Patricia M. Hill (UK) * Kung-Kiu Lau (UK) * Fabio Martinelli (Italy) * Alberto Pettorossi (Italy) * Andreas Podelski (Germany) * C.R. Ramakrishnan (USA) * Abhik Roychoudhury (Singapore) * Wim Vanhoof (Belgium) * German Vidal (Spain) Important dates * submission deadline for extended abstracts: May 17, 2004 (extended, strict) * Notification: June 4 * Camera-ready: June 16 Sponsor Lopstr 2004 is sponsored by the Association for Logic Programming (ALP) http::/www.cwi.nl/projects/alp

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Call for Participation: Fourth International Workshop on Reduction Strategies in Rewriting and Programming (WRS'04)
by Salvador Lucas 12 May '04

12 May '04

=============================================================== Final call for participation, WRS'04, June 2, 2004. We apologize for multiple copies of this announcements =============================================================== *************************************** * * * WRS'04 CALL FOR PARTICIPATION * * * *************************************** The Fourth International Workshop on Reduction Strategies in Rewriting and Programming (WRS'04) will be held on June, 2, 2003, in Aachen, Germany, as a part of the Federated Conference on Rewriting, Deduction, and Programming (RDP'04). INVITED TALKS will be given by: * Olivier Danvy (University of Aarhus, Denmark), Normalization by Evaluation * Jan Willem Klop (Vrije Universiteit Amsterdam, The Netherlands), Reduction Cycles ROUND TABLE Strategies in Programming Languages Today * Moderator: Salvador Lucas * Speakers: Francisco Duran, Claude Kirchner, Ralf Laemmel PROGRAM Reduction Cycles (invited talk) Jan Willem Klop Autowrite: A Tool for Term Rewrite Systems and Tree Automata Irene Durand Integrating Decision Procedures in Reflective Rewriting-Based Theorem Provers Manuel Clavel, Miguel Palomino, Juan Santa-Cruz Some Undecidable Approximations of TRSs Jeroen Ketema Normalization by Evaluation (invited talk) Olivier Danvy Invariant-Driven Strategies for Maude Francisco Duran, Manuel Roldan and Antonio Vallecillo DS-forest: A Data Structure for Fast Normalization and Efficiently Implementing Strategies (position paper) Rakesh Verma and James Thigpen Strategies in Programming Languages Today (round table) Salvador Lucas moderator Maude's Internal Strategies (round table paper) Francisco Duran Strategic Rewriting (round table paper) Claude Kirchner Programmable rewriting strategies in Haskell (round table paper) Ralf Laemmel WEBSITE http://www-i2.informatik.rwth-aachen.de/WRS04/ For further questions please contact the program co-chairs: Sergio Antoy and Yoshihito Toyama at wrs04(a)redstar.cs.pdx.edu.

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[Haskell] Call for Participation: Fourth International Workshop on Reduction Strategies in Rewriting and Programming (WRS'04)
by Sergio Antoy 10 May '04

10 May '04

=============================================================== Final call for participation, WRS'04, June 2, 2004. We apologize for multiple copies of this announcements =============================================================== *************************************** * * * WRS'04 CALL FOR PARTICIPATION * * * *************************************** The Fourth International Workshop on Reduction Strategies in Rewriting and Programming (WRS'04) will be held on June, 2, 2003, in Aachen, Germany, as a part of the Federated Conference on Rewriting, Deduction, and Programming (RDP'04). INVITED TALKS will be given by: * Olivier Danvy (University of Aarhus, Denmark), Normalization by Evaluation * Jan Willem Klop (Vrije Universiteit Amsterdam, The Netherlands), Reduction Cycles ROUND TABLE Strategies in Programming Languages Today * Moderator: Salvador Lucas * Speakers: Francisco Duran, Claude Kirchner, Ralf Laemmel PROGRAM Reduction Cycles (invited talk) Jan Willem Klop Autowrite: A Tool for Term Rewrite Systems and Tree Automata Irene Durand Integrating Decision Procedures in Reflective Rewriting-Based Theorem Provers Manuel Clavel, Miguel Palomino, Juan Santa-Cruz Some Undecidable Approximations of TRSs Jeroen Ketema Normalization by Evaluation (invited talk) Olivier Danvy Invariant-Driven Strategies for Maude Francisco Duran, Manuel Roldan and Antonio Vallecillo DS-forest: A Data Structure for Fast Normalization and Efficiently Implementing Strategies (position paper) Rakesh Verma and James Thigpen Strategies in Programming Languages Today (round table) Salvador Lucas moderator Maude's Internal Strategies (round table paper) Francisco Duran Strategic Rewriting (round table paper) Claude Kirchner Programmable rewriting strategies in Haskell (round table paper) Ralf Laemmel WEBSITE http://www-i2.informatik.rwth-aachen.de/WRS04/ For further questions please contact the program co-chairs: Sergio Antoy and Yoshihito Toyama at wrs04(a)redstar.cs.pdx.edu.

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Re: [Haskell] Queues / Lists with unbound tails
by andrew cooke 08 May '04

08 May '04

Claus Reinke said: > You can't really pop from a fixed-length queue. Apart from that, something like this? Just to clarify, I want something with a *single* operation that takes one value, adding it to the front of the queue, and returns a tuple containing the value that was at the end of the queue and a new queue, with the new value at the front, and without the returned value at the end. See the QUEUE type in my email. So when you push at the front, something pops off the end. If that's not a queue, or not pushing, or not popping then please ignore the words, and just go with the idea. Thanks, Andrew -- ` __ _ __ ___ ___| |_____ work web site: http://www.ctio.noao.edu/~andrew / _` / _/ _ \/ _ \ / / -_) personal web site: http://www.acooke.org/andrew \__,_\__\___/\___/_\_\___| list: http://www.acooke.org/andrew/compute.html

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New release of Vital
by Keith Hanna 05 May '04

05 May '04

I am happy to announce a new release of Vital, a document-centered implementation of Haskell. Recently additioins include: * Hyperlinks, that provide an easy way of navigating between Vital documents; * Some new Vital documents, including a tutorial presentation of approaches to Exact Real Arithmetic (illustrating the infinite decimal expansion of pi, based upon Jerzy Karczmarczuk's philosophical musings on the subject and Jeremy Gibbon's recently discovered "spigot" algorithms); * A new website with lots of supporting materials. And, of course, there is the usual tidying-up of loose ends. The home page for Vital is at: http://www.cs.kent.ac.uk/projects/vital/ As before, the Vital system can be run via the web. Enjoy! Keith Hanna Univ of Kent, UK ---------------------------------------------------------------------------- Vital is a document-centered implementation of [a subset of] Haskell. It aims to present Haskell in a form suitable for end users in application areas such as engineering, mathematics and finance who often need a combination of: * the expressiveness and robustness that languages like Haskell can provide, with * a 'live' document-centered gui in which programs and results are presented together, and solutions to problems can be incrementally developed. Vital may also be useful in teaching/demonstrating some of the principles of functional programming. The main features of the Vital approach are: * Haskell modules are presented as 'documents'. A document is a free-format collection of declarations and expressions with their values shown alongside. * Documents may be developed interactively and (like a spreadsheet) are 'live' in the sense that any change to a document automatically results in dependent values being updated. * Hyperlinked comments provide an easy means for a user to navigate between related documents. * Data structures may be displayed in diagrammatic form by associating 'styles' with their declarations. For example, a value of a Tree datatype may be graphically displayed as a tree. * Styles are ordinary Haskell values. Definitions for styles may be gathered together as a 'stylesheet', itself an ordinary module. * Documents are notionally unbounded in extent and may be panned, allowing any region of a large or infinite data structure to be displayed. * 'Direct manipulation' of diagrammatically-displayed data structures is supported (with changes being reflected back into the Haskell source code). For example, using mouse gestures, a subtree of a tree may be selected, copied to the clipboard and subsequently pasted into another node of a tree. * Images ( both bit-mapped and synthetic) may be displayed. * Documents may be saved as ordinary Haskell text files (with layout data, etc. embedded in comments). At present, the Vital system supports only a subset of Haskell and type-checking is carried out dynamically (ie, at run time) -- but watch this space for forthcoming work on static type checking and type classes.

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All About Monads tutorial missing
by Bayley, Alistair 05 May '04

05 May '04

Jeff Newbern's "All About Monads" tutorial seems to have vanished; or rather, the domain name seems to have changed owner: http://www.nomaware.com/monads/html/ There seems to be a version of the tutorial here (is it up to date?): http://www.lifl.fr/~boulet/formation/CALP/man/monads/html/ ----------------------------------------- ***************************************************************** Confidentiality Note: The information contained in this message, and any attachments, may contain confidential and/or privileged material. It is intended solely for the person(s) or entity to which it is addressed. Any review, retransmission, dissemination, or taking of any action in reliance upon this information by persons or entities other than the intended recipient(s) is prohibited. If you received this in error, please contact the sender and delete the material from any computer. *****************************************************************

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Haskell on OpenBSD
by dons＠cse.unsw.edu.au 05 May '04

05 May '04

I'm maintaining a page covering "Haskell on OpenBSD", along the lines[1] of the FreeBSD page: www.haskell.org/freebsd. I'll try to keep it a current snapshot of Haskell compilers, tools and libraries on this OS. http://www.cse.unsw.edu.au/~dons/haskell_openbsd.html Cheers, Don [1] If you look closely, you'll see that the OpenBSD page is rather similar to the FreeBSD page, though not quite as pretty. Thanks Oliver!

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