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Implementing RefMonads in Haskell without ST,IO
by Tim Sweeney 04 Jun '03

04 Jun '03

Given the common definition of RefMonad: class Monad m => RefMonad m r | m -> r where newRef :: a -> m (r a) readRef :: r a -> m a writeRef :: r a -> a -> m () Is it possible to actually implement a working instance of RefMonad in Haskell, without making use of a built-in monad like IO or ST? If so, I'd love any tips -- I've been making good use of monads for a while, but can't figure this one out. The Java programmer in me wants to implement RefMonad by passing around a function from integers (think of them as pointers or heap indices) to "objects", and in readRef, "cast" the "object" to the appropriate type "t". If it's not possible to implement a typesafe RefMonad instance directly in Haskell, without making use of built-in imperative features like IO, then doesn't this refute the claims that monads implement imperative features functionally? -Tim

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labelled fields
by Steffen Mazanek 03 Jun '03

03 Jun '03

Hello, I need something like data Type = TCon String {lmtc::Maybe String} ... but this does not seem to be possible. Instead I have to waste identifiers: data Type = TCon {senseless::String,lmtc::Maybe String} ... Why? Are there any formal reasons against the above declaration? Or do I miss something? Thanks, Steffen -- Steffen Mazanek - www.steffen-mazanek.de - GPG: 791F DCB3 Haskell, that's where I just curry until fail, unwords any error, drop all undefined, maybe break, otherwise in sequence span isControl and take max $, id: (d:[])

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Foclasa: Last Call for Papers
by Jean-Marie JACQUET 03 Jun '03

03 Jun '03

[ Our apologies for multiple copies. ] ====================================================================== 2nd International Workshop on Foundations of Coordination Languages and Software Architectures (Foclasa 2002) September 2, 2003, Marseille, France Workshop affiliated to CONCUR'2003, 02 - 06 September 2003. http://www.info.fundp.ac.be/~jmj/Foclasa03.html ====================================================================== SCOPE AND TOPICS Modern information systems rely more and more on combining concurrent, distributed, mobile and heterogenous components. This move from old systems, typically conceived in isolation, induces the need for new languages and software architectures. In particular, coordination languages have been proposed to cleanly separate computational aspects and communication. On the other hand, software architects face the problem of specifying and reasoning on non-functional requirements. All these issues are widely perceived as fundamental to improve software productivity, enhance maintainability, advocate modularity, promote reusability, and lead to systems more tractable and more amenable to verification and global analysis. The aim of the workshop is to bring together researchers working on the foundations of component-based computing, coordination, and software architectures. Topics of interest include (but are not limited to): o Theoretical models for coordination (component composition, concurrency, dynamic aspects of coordination, semantics, expressiveness); o Specification, refinement, and analysis of software archi- tectures (patterns and styles, verification of functional and non-functional properties); o Coordination, architectural, and interface description languages (implementation, interoperability, heterogeneity); o Agent-oriented languages (formal models for interacting agents); o Dynamic software architectures (mobile agents, configuration, reconfiguration); o Modeling of information systems (groupware, internet and the web, workflow management, CSCW and multimedia applications) o Coordination patterns (mobile computing, internet computing); o Tools and environments for the development of coordinated applications o Methodologies for validating and certifying software compositions SUBMISSION GUIDELINES Papers describing original work are solicited as contributions to Foclasa. Submitted papers should be limited to 6 000 words, preferrably formatted according to the Electronical Notes in Theoretical Computer Science. They should be emailed as PostScript (PS) or Portable Document Format (PDF) files to jmj(a)info.fundp.ac.be. PUBLICATION Following the previous edition, the proceedings will be published as a volume of the Electronical Notes in Theoretical Computer Science. Selected papers will be published in a special issue of the journal Science of Computer Programming. IMPORTANT DATES: o June 9, 2003: Submission deadline. o July 15, 2003: Notification of acceptance. o August 25, 2003: Final version. o September 2, 2003: Meeting Date. LOCATION The workshop will be held in Marseille in September 2003. It is a satellite workshop of CONCUR 2003. For venue and registration see the CONCUR web page at http://concur03.univ-mrs.fr/ WORKSHOP ORGANIZERS o Antonio Brogi (University of Pisa, Italy) o Jean-Marie Jacquet (University of Namur, Belgium) o Ernesto Pimentel (University of Malaga, Spain) PROGRAMME COMITTEE: o Farhad Arbab (CWI, The Netherlands) o Antonio Brogi (University of Pisa, Italy) - Co-chair o Manfred Broy (University of Munich, Germany) o Jeff Kramer (Imperial College, United Kingdom) o Paola Inverardi (Univerity L'Aquila, Italy) o Jean-Marie Jacquet (University of Namur, Belgium) - Co-chair o Joost Kok (University of Leiden, The Netherlands) o Ernesto Pimentel (University of Malaga, Spain) - Co-chair o Antonio Porto (New University of Lisbon, Portugal) o Catalin Roman (Washington University, USA) o Pamela Zave (AT&T Labs Research, USA)

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ESS2003: ELSNET Summer School on CALL
by Steven Krauwer 03 Jun '03

03 Jun '03

REMINDER: Still places available CALL for PARTICIPATION The 11th ELSNET Summer School on Language and Speech Communication Topic: Language and Speech Technology in Language Learning Lille (France), Monday July 7 - Friday July 18, 2003 http://www.univ-lille3.fr/ESS2003 Organized by the University of Lille 3 For the 11th ELSNET Summer School we have chosen a topic of great relevance to researchers and developers in Europe and in other multilingual environments: the use of language and speech technology in language learning, both of spoken and of written language. The goal of this workshop is to get young researchers on a track that will eventually contribute to an important application area. The underlying vision (or dream) is The automatic animated language tutor. + Audience and aims: We see the school as mainly research and development oriented, and hence the primary audience are researchers, developers and integrators who will make our vision happen (rather than teachers who would use it). Both technological and pedagogical aspects will be taken into consideration The aims are: * to make the students familiar with the main principles and problems of language learning/teaching * to make them familiar with current best practice in computer assisted language learning * to make them familiar with the main challenges in computer assisted language learning Participants are expected to have a general computational background and some familiarity with language or speech research and/or processing. After completion of the summer school participants should be able to function in teams aimed at designing or implementing tools, environments or courses for Computer Assisted Language Learning (abbreviated CALL). All students attend the same full programme, except for the hands-on sessions, where students can sign up for either NLP or Speech oriented streams. In special student sessions students can present their own work. The presentations will be published on the ELSNET website. The working language of the Summer School will be English. + Fees: Category Late registration fee (euro) Students 140 Academic staff 280 Commercial organisations 560 ELSNET members are entitled to a 20% discount + Food and accommodation: The cost of accommodation (on campus) will be ca 10 euro per night for students. Lunch and evening meals will be provided during course days. + Registration, grants and other information: For detailed information about programme, registration procedures and deadlines, fees, accommodation, grant possibilities, venue, course and social programme, etc visit the ESS2003 website at http://www.univ-lille3.fr/ESS2003 or send an email to the local organizers at elsnetadmin(a)univ-lille3.fr Creditcard payment is now possible. A limited number of grants (covering the cost of accommodation) may be available. Details and application forms can be found on the website. __________________________________________________________________________ Steven Krauwer, ELSNET coordinator, UiL-OTS, Trans 10, 3512 JK Utrecht, NL phone: +31 30 253 6050, fax: +31 30 253 6000, email: s.krauwer(a)elsnet.org http://www.elsnet.org

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CFP: ACM SAC'04 Programming Languages Track
by Marjan Mernik 03 Jun '03

03 Jun '03

[Sorry for multiple copies] ---------------------------------------------------------------------------------- CALL FOR PAPERS =============== SAC'04 - ACM 2004 SYMPOSIUM ON APPLIED COMPUTING March 14-17, 2004 Nicosia, Cyprus Technical Track on "Programming Languages" <Track Chairs> Chang-Hyun Jo <jo(a)ecs.fullerton.edu> California State University, Fullerton, USA Marjan Mernik <marjan.mernik(a)uni-mb.si> University of Maribor, Slovenia Barrett Bryant < bryant(a)cis.uab.edu> The University of Alabama at Birmingham, USA SAC '04 Over the past eighteen years, the ACM Symposium on Applied Computing has become a primary forum for applied computer scientists, computer engineers, software engineers, and application developers from around the world to interact and present their work. SAC 2004 is sponsored by the ACM Special Interest Group on Applied Computing (SIGAPP). For additional information, please check the SAC web page: "http://www.acm.org/conferences/sac/sac2004". This document is also available at "http://www.ecs.fullerton.edu/~jo/sac/" and "http://www.ecs.fullerton.edu/~jo/sac/sac2004-PL-CFP.pdf". PROGRAMMING LANGUAGES (PL) Track A technical track on Programming Languages will be held at SAC'04. It will be a forum for engineers, researchers and practitioners throughout the world to share technical ideas and experiences relating to implementation and application of programming languages. Original papers and experience reports are invited in all areas of programming languages. Major topics of interest include but are not limited to the following: Compiling Techniques Domain-Specific Languages Formal Semantics and Syntax Garbage Collection Language Design and Implementation New Programming Language Ideas and Concepts New Programming Paradigms Practical Experiences with Programming Languages Program Analysis and Verification Program Generation and Transformation Programming Languages from All Paradigms (Agent-Oriented, Aspect-Oriented, Functional, Logic, Object-Oriented, etc.) Visual Programming Languages GUIDELINES FOR SUBMISSION Authors are invited to contribute original papers in all areas of experimental computing and application development relevant to the theme of the track. This includes the following categories of submissions: 1) Original and unpublished research work, 2) Reports of innovative applications to the arts, sciences, engineering, and business areas, 3) Reports of successful technology transfer to new problem domains, 4) Reports of industrial experience and demos of new innovative systems. All submissions will be peer reviewed. Papers will be selected based on their originality, timeliness, significance, relevance and clarity of presentation. Accepted papers will be published in the symposium proceedings. Expanded versions of the accepted papers will be considered for publication in the ACM/SIGAPP quarterly Applied Computing Review. A set of selected papers, which did not get accepted as full papers, will be accepted as poster papers and will be published as extended 2-page abstracts in the symposium proceedings. The following submission guidelines must be strictly followed: * Submit the original manuscripts in an electronic format to: <sacpl(a)ecs.fullerton.edu>. The file format should be PDF. The title of the submission should be the last name of the first author (e.g., If the first author is John Smith then the submission should be titled as "smith.pdf"). * The author(s) name(s) and address(es) must NOT appear in the body of the paper, and self-reference should be in the third person. This is to facilitate blind review. Only the title should be shown at the first page without the author's information. * A separate cover sheet should show the title of the paper, the author(s) name(s) and affiliation(s), and the address (including e-mail, telephone, and FAX) to which correspondence should be sent. This sheet should also be submitted in an electronic format to <sacpl(a)ecs.fullerton.edu> and it should be titled as "smith-cover.pdf". * The body of paper should not exceed 4,000 words (approximately 15 pages, double-spaced, 12-point size). You may refer to the final copy format at "http://www.acm.org/sigs/pubs/proceed/template.html". The total number of final pages without any extra page charge will be 5. * An abstract including the title of the paper at the beginning (without having any author's information) as a separate text file should be submitted. It should be titled as "smith-abstract.txt" * Submit a cover page (PDF format), a manuscript (PDF format) and an abstract (TEXT format) as attachments to your email. Your submission email text should include the author(s) name(s), the title, and a contact point (name and email address) you prefer. * All submissions must be received by September 6, 2003. IMPORTANT DATES September 6, 2003: Paper Submissions October 18, 2003: Author Notification November 8, 2003: Camera-Ready Copy March 14-17, 2004: Conference at Nicosia, Cyprus The SAC 2004 Programming Language Track Program Committee Members Mikhail Auguston, Naval Postgraduate School, USA Shigeru Chiba, Tokyo Institute of Technology, Japan Kyung-Goo Doh, Hanyang University, Korea Maurizio Gabbrielli, University of Bologna, Italy Tim Harris, Cambridge University, UK Pedro Henriques, University of Braga, Portugal Ho-fung Leung, The Chinese University of Hong Kong, Hong Kong, China Rafael Lins, Federal University of Pernambuco, Brazil Pablo Martinez, National University of La Plata, Argentina Crist'obal Pareja-Flores, Complutense University of Madrid, Spain Lori Pollock, University of Delaware, USA Guenter Riedewald, University of Rostock, Germany Tony Sloane, Macquarie University, Australia Peter Thiemann, University of Frieburg, Germany Dave Wile, Teknowledge Corp., USA Juergen Winkler, Friedrich Schiller University, Germany Information for Other Related Tracks For prospective authors of papers that specifically focus on the improvements to the object-oriented domain (e.g., OO languages, OO systems, OO architectures) please also look at the Object Oriented Programming and Systems Track at "http://oops.disi.unige.it/" and "http://www.acm.org/conferences/sac/sac2004/tech_tracks.htm".

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Eval in Haskell
by oleg＠pobox.com 03 Jun '03

03 Jun '03

Simon Marlow wrote: > The test driver makes use of 'eval'-style scripting, which none of the > existing Haskell systems has. Doesn't the following qualify as eval? A similar code works even in Hugs. > import System (system, ExitCode(ExitSuccess)) > import Posix(executeFile) > > myconfig_file = "/tmp/config" > > phaseII_var = "/tmp/Config.hs" > phaseII_const = "/tmp/a.hs" > phaseII_eval = "ghc --make " > phaseII_result = "/tmp/a.out" > > nl = "\n" > > writeConfig :: Int -> IO () > writeConfig num = > do > writeFile phaseII_var $ > concat > ["module Config (config_item) where", nl, > "config_item =", show num, nl] > > > runSuperIO () = system (phaseII_eval ++ > phaseII_const ++ " -o " ++ phaseII_result) > >>= \ExitSuccess -> > executeFile phaseII_result False [] Nothing > > main = readFile myconfig_file >>= writeConfig . read >>= runSuperIO The context: http://www.haskell.org/pipermail/haskell-cafe/2003-February/003912.html Furthermore, if GHCi can (after some prodding by the user) launch ghc to compile a module and then load the resulting .o file in and apply some function in thus loaded file, doesn't it feel like an eval?

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LOPSTR 2003 (Call for Abstracts)
by Wim Vanhoof 02 Jun '03

02 Jun '03

With apology for multiples copies. Deadline for abstracts June 8 ---------------------------------------------------------------------- International Symposium on Logic-based Program Synthesis and Transformation, LOPSTR'03 August 25 - 27, 2003 Uppsala, Sweden ---------------------------------------------------------- CALL FOR ABSTRACTS ----------------------------------------------------------- http://www.cs.kuleuven.ac.be/~dtai/lopstr03/ ----------------------------------------------------------- The aim of the LOPSTR series is to stimulate and promote international research and collaboration on logic-based program development, and the symposium is open to contributions in logic-based program development in any language paradigm. LOPSTR 2003 will be held at the University of Uppsala, as part of PLI 2003 (Principles, Logics, and Implementation of High-Level Programming Languages), a confederation of conferences and workshops including ICFP 2003 (ACM-SIGPLAN International Conference on Functional Programming) and PPDP 2003 (ACM-SIGPLAN International Conference on Principles and Practice of Declarative Programming). Past events 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). 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 has a strong workshop character, in the sense that it is also intended to provide useful feedback to authors on their preliminary research. Formal proceedings of the symposium are produced only after the symposium, so that authors can incorporate this feedback in the published papers. Scope of the Symposium We solicit extended abstracts describing recent work or work in progress. 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 * composition * reuse * optimisation * applications and tools * component-based software development * agent-based software development * software architectures * design patterns and frameworks * program refinement and logics for refinement * proofs as programs Submission Guidelines Authors can submit extended abstracts of approximately 6 pages with a maximum of 10 pages describing recent work or work in progress. Contributions should be written in English and should be submitted electronically in Postscript or PDF format to the program chairman at the following email address: Maurice.Bruynooghe(a)cs.kuleuven.ac.be. Prospective authors who have difficulties for the electronic submission may contact the chairman. Accepted papers have to be presented at the Symposium by one of the authors and will appear in the informal pre-proceedings distributed at the Symposium. Formal Proceedings After the symposium, authors of abstracts that are judged mature for publication will be invited to submit a full paper describing original work neither published nor submitted elsewhere. These will be reviewed according to the usual refereeing procedures, and accepted papers will be published in a final collection of papers which are expected to be published in the Lecture Notes in Computer Science series by Springer-Verlag. Important Dates June 8, 2003: submission deadline for extended abstracts June 24, 2003: notification of authors of abstracts August 1, 2003: deadline for informal pre-proceedings December 1, 2003: submission deadline for revised papers February 1, 2004: notification of authors Program Committee Elvira Albert (Spain) Roland Bol (Sweden) LOCAL ORGANISOR Maurice Bruynooghe (Belgium) PROGRAMME CHAIR Michael Butler (UK) Jim Caldwell (USA) Wlodek Drabent (Poland) Tom Ellman (USA) Norbert E. Fuchs (Switzerland) Robert Glück (Japan) Gopal Gupta (USA) Ian Hayes (Australia) Catholijn Jonker (the Netherlands) Andy King (UK) Mario Ornaghi (Italy) Maurizio Proietti (Italy) German Puebla (Spain) Julian Richardson (USA) Olivier Ridoux (France) Sabina Rossi (Italy) Wim Vanhoof (Belgium)

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lecture
by Filip 02 Jun '03

02 Jun '03

Hi, I am student of Computer Science and I have to write a lecture on ghc network module. Where can I get some code samples of this module. I am looking for short progrmas that show how to use network module. Thanks.

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RE: ANNOUNCE: GHC version 6.0
by Simon Peyton-Jones 30 May '03

30 May '03

| > We are pleased to announce a new major release of the Glasgow Haskell | > Compiler (GHC), version 6.0. | | The release notes make me very happy :) There is a broken link: | | http://www.haskell.org/ghc/docs/latest/html/base/Data.Generics.html Yes, we found that yesterday. Fix committed to the HEAD. We'll put up a substitute shortly S

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class MonadPlus m => MonadRing m
by Tim Sweeney 30 May '03

30 May '03

class MonadPlus m => MonadRing m where mone :: m a ** :: m a -> m a -> m a Does anybody have experience with a construct like MonadRing above? I'm interested in prior implementations, examples of instances, and coherence rules. A conceptual example: consider ListMonad, used to implement "non-determinism", or computations that may produce multiple values. In this context, the order or duplication of elements in a list is not significant; we think of them as sets of values: >From Functor: fmap f xs -- apply a function to all elements in the set, and collect the results in a set >From Monad: xs>>=f -- apply a set-returning function to all elements of x, and merge all the results into a set return xs -- generate a singleton set containing only x >From MonadPlus: mzero -- the empty set xs++ys -- the union of sets xs and ys >From MonadRing: xs ** ys -- the intersection of the sets xs and ys. mone -- the unit of **. conceptually, "the set of all sets". With Haskell's type system, this notion isn't feasible with ListMonad directly, but could be used with similar "set-like" monads containing elements drawn from a finite set. For set-like monads, there is then a further notion of a partial order relation defined by set inclusion. This could be defined along the lines of "mcontains :: m a -> m b -> m bool". For ListMonad, mcontains xs ys can be defined as true iff xs contains all elements of ys, in order, allowing arbitrary new elements that happen to occur between them. I'm not sure of the practical utility of these constructs in the Haskell world, but I've been working with them for a while in an experimental language and have found them very powerful, especially when coupled with first-class types with set-like functionality a la David McAllester "Ontic" language. In my particular case, I have found the following syntactic sugar to aid a great deal in the readability of complex monad expressions: -- Non-monad constructs: f(x) -- call function f with parameter x let x=v in e -- let-binding. -- Functor syntactic sugar: f($x) -- like map f x let x$=v in e -- like map (\x -> e) x -- Monad syntactic sugar: f(%x) -- like x >>= f let x%=v in e -- like v >>= \x -> e This could be considered a syntactic alternative to the "do" notation and list comprehension notation. -Tim Sweeney

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