- Haskell - Haskell.org

.hi files
by Arun Kumar S Jadhav 11 Jul '03

11 Jul '03

Hi all, Can any one tell me what is the use of .hi (interface) files. I want to know the steps involved in the compilation of a .hs file. I went thru the what nhc98 roughly does and saw that it generates interface file for each module. Please enlighten as to what is the precise function of interface files. Regards, -- Arun Kumar S Jadhav Masters Student, SIC-309, KReSIT, IIT-Bombay, India Ph: +91-22-25764967 http://www.it.iitb.ac.in/~arunk ***************************** Never negotiate out of fear Never fear to negotiate *****************************

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CFP: CLIMA IV - 4th Intl. Workshop on Computational Logic in Multi-Agent Systems
by João Alexandre Leite 11 Jul '03

11 Jul '03

========================================================================== FIRST CALL FOR PAPERS CLIMA IV Fourth International Workshop on Computational Logic in Multi-Agent Systems January 6-7, 2004, Fort Lauderdale, Florida, USA http://centria.di.fct.unl.pt/~jleite/climaIV/index.htm Post-Proceedings will be published in Springer Verlag LNAI Submission Deadline: September 19th Co-located with the 7th LPNMR and the 8th AIMATH =========================================================================== Over recent years, the notion of agency has claimed a major role in defining the trends of modern research. Influencing a broad spectrum of disciplines such as Sociology, Psychology, Philosophy and many more, the agent paradigm virtually invaded every sub-field of Computer Science, not least because of the Internet and Robotics. Multi-agent Systems (MAS) are communities of problem-solving entities that can perceive and act upon their environments to achieve their individual goals as well as joint goals. The work on such systems integrates many technologies and concepts in artificial intelligence and other areas of computing. There is a full spectrum of MAS applications that have been and are being developed; from search engines, educational aids to electronic commerce and trade. Although commonly implemented by means of imperative languages, mainly for reasons of efficiency, the agent concept has recently increased its influence in the research and development of computational logic based systems. Computational Logic, by virtue of its nature both in substance and method, provides a well-defined, general, and rigorous framework for systematically studying computation, be it syntax, semantics, procedures, or implementations, environments, tools, and standards. The purpose of this workshop is to discuss techniques, based on computational logic, for representing, programming and reasoning about multi-agent systems in a formal way. This is clearly a major challenge for computational logic, to deal with real world issues and applications. Following the workshop on Multi-Agent Systems in Logic Programming affiliated with ICLP'99, the first CLIMA workshop took place in London, UK, affiliated with CL'2000. The 2001 edition of CLIMA, took place in Paphos, Cyprus, affiliated with ICLP'01. CLIMA'02 took place in Copenhagen, Denmark, and was affiliated with ICLP'02 and part of FLOC'02. We solicit unpublished papers that address formal approaches to multi-agent systems. The approaches as well asbeing formal must make a significant contribution to the practice of multi-agent systems. Relevant techniques include, but are not limited to, the following: * Nonmonotonic reasoning in MAS * Planning under incomplete information in MAS * Logical foundations of MAS * Usage of abduction in MAS * Representation of knowledge and belief in MAS * Knowledge and belief updates in MAS * Temporal reasoning for MAS * Theory of argumentation for MAS * Negotiation and co-operation for MAS * Communication languages for MAS * Distributed constraint satisfaction in MAS * Modal logic approaches to MAS * Logic based programming languages for MAS * Distributed theorem proving for MAS * Logic based implementations of MAS * Decision theory for MAS * Logic based agents for the Internet SUBMISSION INSTRUCTIONS We welcome and encourage the submission of high quality, original papers, which are not simultaneously submitted for publication elsewhere. Please refer to the workshop web pages for further instructions concerning the submission procedures. IMPORTANT DATES * Submission: September 19th, 2003 * Notification of Acceptance: October 17th, 2003 * Final version due: November 13th, 2003 * CLIMA IV: January 6-7th, 2004 PROCEEDINGS Post-proceedings will be published by Springer-Verlag as a volume of the Lecture Notes on Artificial Intelligence (LNAI) series. Informal proceedings will be available at the workshop and online. PROGRAM COMMITTEE * Chitta Baral, Arizona State University, USA * Gerd Brewka, University of Leipzig, Germany * Jürgen Dix, The University of Manchester, UK * Thomas Eiter, Vienna University of Technology, Austria * Klaus Fischer, DFKI, Germany * Michael Fisher, University of Liverpool, UK * James Harland, Royal Melbourne Inst. of Tech., Australia * Katsumi Inoue, Kobe University, Japan * Gerhard Lakemeyer, Aachen Univ. of Technology, Germany * João Leite, New University of Lisbon, Portugal * Yves Lespérance, York University, Canada * John Jules Ch. Meyer, Univ. of Utrecht, The Netherlands * Leora Morgenstern, IBM, USA * Luís Moniz Pereira, New University of Lisbon, Portugal * Fariba Sadri, Imperial College, UK * Ken Satoh, National Institute of Informatics, Japan * Renate Schmidt, The University of Manchester, UK * Guillermo Simari, Universidad Nacional del Sur, Argentina * V. S. Subrahmanian, University of Maryland, USA * Francesca Toni, Imperial College, UK * Paolo Torroni, University of Bologna, Italy * Wiebe van der Hoek, University of Liverpool, UK * Cees Witteveen, Delft Univ. of Tech., The Netherlands WORKSHOP ORGANIZERS: * Jürgen Dix, The University of Manchester, UK (dix(a)cs.man.ac.uk) * João Leite, New University of Lisbon, Portugal (jleite(a)di.fct.unl.pt) INQUIRIES: Please send program suggestions and inquires to either of the organizers.

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constructors in O'Haskell
by Peter Padawitz 11 Jul '03

11 Jul '03

How may I hide constructors in O'Haskell 'cause export lists don't work in this language? Peter

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Monad constructors
by Peter Padawitz 11 Jul '03

11 Jul '03

Why must every Monad instance be a datatype or newtype, even if there will be just a single constructor? Peter

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RE: How overload operator in Haskell?
by Hal Daume 09 Jul '03

09 Jul '03

Quite right :). I agree whole-heartedly. There's nothing wrong with overloading (+) and (-) in this case, but the rest really don't make much sense. Probably best to leave them undefined and just not use them. Then you could define your own dot product function and the like. -- Hal Daume III | hdaume(a)isi.edu "Arrest this man, he talks in maths." | www.isi.edu/~hdaume > -----Original Message----- > From: haskell-admin(a)haskell.org > [mailto:haskell-admin@haskell.org] On Behalf Of Jerzy Karczmarczuk > Sent: Wednesday, July 09, 2003 8:25 AM > To: haskell(a)haskell.org > Subject: Re: How overload operator in Haskell? While this is a possible solution, I would shout loudly: "Arrest this man, he is disrespectful wrt math!". Actually, this shows once more that the Num class and its relatives is a horror... Signum in this context has no sense. The multiplication might be the cross product, but its anti-commutativity shows plainly that this is not a 'standard' multiplication. 'fromInteger' has even less sense than signum... I am particularly horrified by "abs v = map abs v", and I am sure all of you see why. I think that a more sane solution would be the definition of a particular class with operations porting names like <+>, or ^+^, or whatever similar to standard ones, but different. Jerzy Karczmarczuk _______________________________________________ Haskell mailing list Haskell(a)haskell.org http://www.haskell.org/mailman/listinfo/haskell

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RE: Reading/Writing Binary Data in Haskell
by Hal Daume 09 Jul '03

09 Jul '03

GHC uses its own version of the NHC library. It's linked off of the libraries page: http://www.pms.informatik.uni-muenchen.de/mitarbeiter/panne/haskell_libs /Binary.html Moreover, I have my own version of this library which we were, for a while, trying to synch with the NHC library so it could become standard. This is available at: http://www.isi.edu/~hdaume/haskell/NewBinary/ and allows both bit-based and byte-based writing styles. -- Hal Daume III | hdaume(a)isi.edu "Arrest this man, he talks in maths." | www.isi.edu/~hdaume > -----Original Message----- > From: haskell-admin(a)haskell.org > [mailto:haskell-admin@haskell.org] On Behalf Of Christian Maeder > Sent: Wednesday, July 09, 2003 1:34 AM > To: The Haskell Mailing List > Subject: Re: Reading/Writing Binary Data in Haskell > > > >>There isn't a standard mechanism for binary I/O. > > > > > > NHC98 contains the York Binary library. Can someone tell me > if this is > > available for other Haskell systems? And didn't GHC also > provide binary I/O? > > How does the GHC itself read/write binary data, since the interface > files (*.hi) produced by GHC are in a binary format? (Whereas > NHC98 *.hi > are text files.) > > Christian > > > _______________________________________________ > Haskell mailing list > Haskell(a)haskell.org > http://www.haskell.org/mailman/listinfo/haskell >

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How overload operator in Haskell?
by Liu Junfeng 09 Jul '03

09 Jul '03

I've learned haskell months, but I still can't understand the type system very well. I can only write: ----------------------------------- type Vector = [Double] vadd,vsub :: Vector->Vector->Vector v1 `vadd` v2 = zipWith (+) v1 v2 v1 `vsub` v2 = zipWith (-) v1 v2 svmul :: Double->Vector->Vector s `svmul` v = map (s*) v ------------------------------------ Tough it works, it is not convenient to use. How to create a Vector type and overload mathematical operators? Thanks for your help. Liu Junfeng liujf(a)softhome.net

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RE: Reading/Writing Binary Data in Haskell
by Simon Peyton-Jones 09 Jul '03

09 Jul '03

A library for reading and writing binary data, portable across both implementations and platforms, has been a long-standing lack. It comes up regularly, and has been discussed recently on the libraries list (libraries(a)haskell.org) Most recently George Russell posted a library, but I don't know it's portability http://haskell.org/pipermail/libraries/2003-June/001227.html There seem to be two slightly different issues: a) writing Haskell data structures to a file, so they can be recovered (exact binary structure of the file is irrelevant) b) reading and writing files whose exact binary structure is specified but presumably much of the infrastructure for both purposes would be the same. The way stands open for someone to take up the challenge: define an interface, agree it with the community, and build an implementation that works. Maybe someone is doing this already? Perhaps George's library is intended to be such a thing? Anyway, it would be a great service. Simon | -----Original Message----- | From: haskell-admin(a)haskell.org [mailto:haskell-admin@haskell.org] On Behalf Of Wolfgang Jeltsch | Sent: 09 July 2003 09:21 | To: The Haskell Mailing List | Subject: Re: Reading/Writing Binary Data in Haskell | | On Wednesday, 2003-07-09, 05:31, Glynn Clements wrote: | > [...] | | > There isn't a standard mechanism for binary I/O. | | NHC98 contains the York Binary library. Can someone tell me if this is | available for other Haskell systems? And didn't GHC also provide binary I/O? | | > However, a simple and fairly generic mechanism for doing this is: | > | > 1. Read in a list of "Char"s with the standard I/O functions. | | This will most likely cause problems under Windows. The reason is that the | standard I/O functions are intended for reading and writing text, and that's | why under Windows the sequence CRLF (#0D#0A) is interpreted as a single LF | (#0A) and EOF (#1A) is interpreted as the end of the file. | | > 2. Use "map (fromIntegral . ord) ..." to get a list of "Word8"s (octets). | | This assumes that the standard I/O functions use a one byte character | encoding. I don't now whether this is guaranteed by the Haskell report. | | > [...] | | Wolfgang | | _______________________________________________ | Haskell mailing list | Haskell(a)haskell.org | http://www.haskell.org/mailman/listinfo/haskell

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literal default value for an unknown type
by Andre W B Furtado 09 Jul '03

09 Jul '03

Is it possible replace the question mark in the following code in order to make defaultMyType return a "don't care" value for b? data MyType t = MyType { a :: Int, b :: t} defaultMyType :: MyType defaultMyType = MyType {a = 0, b = ?} Cheers, -- Andre

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[CfP] Special Issue on SEMANTICS AND COST MODELS FOR HIGH-LEVEL PARALLEL PROGRAMMING
by F. Loulergue 08 Jul '03

08 Jul '03

[Please accept our apologies if you receive multiple copies of this CFP] ------------------------------------------------------- 1st CALL FOR PAPERS Special Issue on SEMANTICS AND COST MODELS FOR HIGH-LEVEL PARALLEL PROGRAMMING to appear in Computer Languages, Systems and Structures http://f.loulergue.free.fr/CLSS ------------------------------------------------------- AIMS AND SCOPE Many applications of computing require performance levels attainable only on parallel architectures. Such systems are now readily available as their price/performance ratio continues to improve. The rapid development of affordable hardware for parallel computing makes the need to develop high-quality parallel software increasingly urgent. Sequential programming has long benefited from high-level programming techniques and tools that have made today's immense range of software economically viable. Two decades of research into high-level parallel programming has produced methods and tools that improve the price/performance ratio of parallel software, and broaden the range of target applications. GRIDs offer tremendous computing power. Nevertheless, this power is far from being effectively exploited. In addition to technical problems related to portability and access, Grid computing needs new programming paradigms. Research on high-level grid programming is particularly relevant. Expressivity and ease of use are not the only concerns of high-level parallel languages. Languages based on formal semantics allow one to prove the correctness of programs, to refine programs, etc. One can also have more confidence in the safety of the programming and execution environments by proving the correctness of compilation, the correctness of lower-level semantics (e.g. abstract machines) with respect to the high-level semantics, etc. These concerns are shared by sequential languages. In parallel programming the need for performance prediction is especially great. For parallel programming, one must use an efficient parallel algorithm right from the start; very often this has little to do with the corresponding sequential algorithm. Thus cost models are needed to allow discrimination between efficient and inefficient parallel algorithms. Such models must be sufficiently simple, abstract, and closely related to the source code to allow the programmer to understand which aspects of the algorithm must be modified to improve efficiency. TOPICS We welcome submission of original, unpublished papers in English on topics including: o Parallel language design and implementation based on semantics o Semantics and/or cost models of algorithmic skeletons and parallel libraries o Semantics and/or cost models of programming languages for GRID computing o Proofs of correctness of high-level parallel programs o Refinement of high-level parallel programs o Parallel program design and optimization based on cost models o Experimental results which validate cost models PAPER SUBMISSION Prospective authors are invited to submit full papers in English presenting original research. Submitted papers must be unpublished and not submitted for publication elsewhere. Papers will go through a rigorous reviewing process. Each paper will be reviewed by the guest editor and researchers from the high-level parallel programming community. Papers should be sent to loulergue(a)univ-paris12.fr with subject "[CLSS Special Issue] Submission" no later than Monday 3 November 2003. An early email with your intention to submit a paper would be greatly appreciated (especially if you have doubts about the relevance of your paper). FORMATTING INSTRUCTIONS Formatting instructions for paper submissions will be available at: http://f.loulergue.free.fr/CLSS IMPORTANT DATES November 3, 2003: Full paper due January 15, 2003: Notification April 15, 2004: Final version due Automn 2004: Expected date of publication GUEST EDITOR Dr. Frederic LOULERGUE Laboratory of Algorithms, Complexity and Logic (LACL) University of Paris Val de Marne 61, avenue du General de Gaulle F-94010 CRETEIL - FRANCE loulergue(a)univ-paris12.fr

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