July 2003 - Haskell - Haskell.org

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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[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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Re: Higher rank types
by Graham Klyne 08 Jul '03

08 Jul '03

I took a quick skim through this -- not closely enough to follow all the details but I still found some useful background understanding. For me, it clarified slightly the role of types on the left and right hand sides of a function arrow, which I've seen mentioned in passing but never explained, but there's still a gap in my grasp of this notion (something to do with types on LHS of arrow being subject to pattern matching?). A lingering question in my mind, which may be pretty irrelevant to your purpose, is the relationship between these higher rank types and GHC's existentially bound types (which also use the 'forall' keyword). (Working as I do with Semantic Web technologies and ideas, I was interested to note your "simple rules ... rather than trying to exploit every ounce of inference". I have similar views regarding the role of inference in semantic web applications. I think it will be interesting to study your inference patterns in detail (when I find time!), and in particular to compare your approach to subsumption with the Description Logic approach favoured by many in the SWeb community.) #g -- At 11:23 07/07/03 +0100, Simon Peyton-Jones wrote: >Dear Haskellers > >For a long time now, Mark Shields and I have been writing a paper >describing GHC's approach to type inference for higher-rank types. >We've finally finished a complete draft: > > Practical type inference for arbitrary-rank types > Simon Peyton Jones and Mark Shields > http://research.microsoft.com/~simonpj/papers/putting/index.htm > >The paper has a strongly tutorial flavour, and comes complete with a >prototype implementation that you can play with. My hope is that, in >addition to describing higher-rank stuff, the paper may serve as a kind >of tutorial on type inference generally, and the use of monads to >support the plumbing in particular. There's nothing really new about >this aspect of the paper, but I don't know of a comparable tutorial that >takes a monadic approach. > >It's still very much a draft, so I'd be very interested in your feedback >about it. > >Simon > >_______________________________________________ >Haskell mailing list >Haskell(a)haskell.org >http://www.haskell.org/mailman/listinfo/haskell ------------------- Graham Klyne <GK(a)NineByNine.org> PGP: 0FAA 69FF C083 000B A2E9 A131 01B9 1C7A DBCA CB5E

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RE: Higher rank types
by Simon Peyton-Jones 08 Jul '03

08 Jul '03

| > The paper has a strongly tutorial flavour, and comes complete with a | > prototype implementation that you can play with. | | Does the prototype implementation not support recursive lets? | | *Main> tcs "let fix = (\\f . f (fix f)) in fix" | Not in scope: `fix' No it does not. As the paper explains. Easy exercise: add recursive lets! Simon

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Higher rank types
by Simon Peyton-Jones 08 Jul '03

08 Jul '03

Dear Haskellers For a long time now, Mark Shields and I have been writing a paper describing GHC's approach to type inference for higher-rank types. We've finally finished a complete draft: Practical type inference for arbitrary-rank types Simon Peyton Jones and Mark Shields http://research.microsoft.com/~simonpj/papers/putting/index.htm The paper has a strongly tutorial flavour, and comes complete with a prototype implementation that you can play with. My hope is that, in addition to describing higher-rank stuff, the paper may serve as a kind of tutorial on type inference generally, and the use of monads to support the plumbing in particular. There's nothing really new about this aspect of the paper, but I don't know of a comparable tutorial that takes a monadic approach. It's still very much a draft, so I'd be very interested in your feedback about it. Simon

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Unary Operators
by Arun Kumar S Jadhav 07 Jul '03

07 Jul '03

Hi All, How to define a new unary operator. E.g: I want to use "/\" for intersection over a list of sets and similarly "\/" for union over a list of sets. I searched haskell98 report but couldn't find any pointers. Please let me know if it's allowed in the first place, if yes then how Regards, -- Arun Kumar S Jadhav Masters Student, SIC-309, KReSIT, IIT-Bombay, Ph: 022-25764967 http://www.it.iitb.ac.in/~arunk ***************************** Never negotiate out of fear Never fear to negotiate *****************************

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ITCLS 2003 CfP - Deadline extended to July 14th, 2003
by Jesus Correas Fernandez 04 Jul '03

04 Jul '03

[ITCLS 2003 CfP - Deadline extended to July 14th, 2003] [Apologies if you receive this more than once] Call for Papers and Participation COLOGNET Workshop on Implementation Technology for Computational Logic Systems (ITCLS 2003) Satellite Workshop of FME 2003 Symposium 9 September 2003, Pisa, Italy http://www.clip.dia.fi.upm.es/Conferences/ITCLS-2003/ CoLogNet, the European Network of Excellence in Computational Logic is organizing the Second Workshop on Implementation Technology for Computational Logic Systems (ITCLS) as a satellite workshop of Formal Methods 2003, to take place in Pisa. The previous edition was held in September 2002 in Madrid, affiliated with Logic-based Program Development and Transformation (LOPSTR'02), and co-located with the International Static Analysis Symposium (SAS'02) and the APPIA-GULP-PRODE Joint Conference on Declarative Programming (AGP'02). The workshop is a forum open to both academia and industry and whose aim is to present and discuss work (possibly in progress) related to the topics mentioned below. The ITCLS workshop builds on the tradition of the series of workshops on Implementations of Logic Programming Systems held in the context of COMPULOG NET, the former Network of Excellence in Computational Logic, but opens up its scope to a broader use of logic and formal methods within computational systems. ITCLS 2003 focuses on implementation techniques from the different areas addressed by CoLogNet. The aim is to bring together researchers from fields such as automated reasoning, formal methods and theorem proving, natural language processing, constraint logic programming, inductive logic programming, non-monotonic logic programming, etc. in order to share common problems and solutions regarding implementation and usability issues which arise in formal and logic-based computational systems. Topics of interest for this workshop include, but are not limited to: * Implementation techniques for all aspects of the implementation of systems related to computational logic and formal systems, including: + Formal Methods and its relationship with Computational Logic, + Compiling Specifications, + Theorem Proving, + Non-monotonic Reasoning, Higher Order, Linear Logics, + Logic Programming, + Constraint Programming, and + Natural Language Processing * Environments for computational logic and formal systems, including: + User-interfaces and User-needs, + Software Development, + Debugging and Visualization Techniques, and + Interfaces to Other (possibly Computational Logic) Systems PROGRAMME The workshop will take place during the afternoon and evening of September 9th. The programme will consist of an invited talk (to be announced later) and the presentation of the accepted papers. SUBMISSIONS AND DEADLINES Authors are invited to contribute to the workshop by submitting extended abstracts (6 pages maximum) or full papers (12 pages maximum) on the workshop themes. Limits are strict, and the llncs format (http://www.springer.de/comp/lncs/authors.html) must be used. Submissions are to be sent in PS or PDF format to the organizing committee by emailing them to: colognet-ws-submission_at_clip.dia.fi.upm.es (substitute _at_ by the @ symbol to send email). Submissions originally prepared with LaTeX are highly encouraged, as this will help in preparing the final proceedings, which will be available at the workshop in printed form, as well as electronically. The table below highlights the important dates: Submission deadline: July 14 Notification to authors: July 31 Camera-ready copies: August 15 Workshop: September 9 ORGANIZING COMMITTEE Jesús Correas, UPM, Madrid, Spain Manuel Hermenegildo, UPM, Madrid, Spain Manuel Carro, UPM, Madrid, Spain Germán Puebla, UPM, Madrid, Spain Christian Schulte, KTH, Stockholm, Sweden Please address any question directly related to the workshop to colognet-ws_at_clip.dia.fi.upm.es (substitute _at_ by @).

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CFP: ICEIS'2004: Workshop on Ubiquitous Computing IWUC'2004
by KOUADRI MOSTEFAOUI Soraya 04 Jul '03

04 Jul '03

> [Apologies if you have received multiple postings] > > CALL FOR PAPERS > ________________________________________________________________ > > International Workshop on Ubiquitous Computing (IWUC 2004) > > April 13-14, 2004 - Porto, Portugal > http://ltodi.est.ips.pt/iceis/workshops/iwuc/iwuc2004-cfp.html > In conjunction with the Sixth International Conference on Enterprise > Information Systems - ICEIS 2004 (<http://www.iceis.org/>) > ________________________________________________________________ > > > Workshop Background and Goals > > The development and availability of new computing and communication > devices, and the increased connectivity between these devices, thanks to > wired and wireless networks, are enabling new opportunities for people to > perform their operations anywhere and anytime. Furthermore, due to the > high acceptance rate of such devices by the user community, it is expected > that these devices will become so pervasive that most users will take them > for granted. Generally known as Ubiquitous Computing (UC), the vision of > UC is to push computational services out of conventional desktop > interfaces into environments characterized by transparent forms of > interactivity. > > Despite the growing interest in UC, there is still some progress to be > made before UC shifts from the research mode to the commercial and > intensive use modes. The support technologies, however, are improving at > an impressive pace. Most of the research and development activities are > currently aimed at improving the devices themselves and the technologies > these devices will use to communicate. At present, the main use of mobile > devices is still voice-oriented, but several indicators show that this is > changing. 3G networks (e.g., GPRS, UMTS) and recent development of > communication and presentation protocols (e.g., XML, WAP) are being > combined to give users a high-quality experience of data-centric services. > > > Besides the central role that hardware infrastructure plays in the > expansion and penetration of UC, other issues still need to be tackled to > better assist developers of UC applications. Developers are put on the > front line of satisfying the promise of businesses and service providers > for delivering Internet content to mobile devices. Indeed, the fact that > an application for mobile users has different requirements, calls for new > techniques to identify and specify these requirements. With regard to > users, it is expected that they will be frequently engaged in complex > operations such as searching the net for better business opportunities. > Therefore, their association with intelligent components, to act as > proxies, is deemed appropriate. UC environments of the near future will be > populated by a large number of computing devices, spread across the > network, and often invisible. These devices need to be coordinated for > better interactions. Devices, whether carried on by people or embedded > into other systems (within the home or at other sites), will constitute a > global networking infrastructure -- and likely to provide a new level of > openness and dynamics. These interactions raise many new issues that draw > upon existing research areas, as well as introduce new research and > development challenges, in technical areas (such as device design, > wireless communication, location sensing, etc), psychology (privacy > concerns, attention focus, multi-person interaction, etc), and design > (direct interaction, work patterns, etc). > > Existing global efforts in Grid Computing also shares some similarities > with the aims of this workshop, although Grid computing at present is > restricted to high-end computational resources. Making the Grid more open, > and accessible to a wider range of users will also require the need to > address similar challenges. > > > Topics of interest > > In this workshop, we aim to identify ecent and significant developments in > the general area of ubiquitous computing. Topics of interests include, but > are not limited to: > - Mobile computing vs. Pervasive computing vs. Ubiquitous computing. > - Design methodologies and evaluation techniques. > - New interfaces and modes of interactions between people and ubiquitous > computing devices, applications or environments. > - Grid Computing technologies for Wireless networks > - Context awareness. > - Agent-based ubiquitous applications. > - Services for ubiquitous applications. > - Middleware for service discovery. > - Integration of wired and wireless networks. > - Enabling technologies such as Bluetooth, 802.11, etc. > - Security and privacy issues. > - Visionary future scenarios. > - Mobile services > - Performance tuning of mobile applications > > > Submission of Papers > > There will be two types of papers: long (approx. 4000 words) and short > (approx. 2000 words). Furthermore, a keynote speaker and a discussion > panel are planned. > > Important Dates > > Full paper submission: December 15, 2003 > Author notification: January 30, 2004 > Camera-ready: February 15, 2004 > > Co-Chairs: > > Soraya Kouadri Mostéfaoui (primary contact) > Dep. of Computer Science > University of Fribourg Switzerland > > Zakaria Maamar > College of Iss Zayed University > Dubai U.A.E > > Omer Rana > School of Computer Science and Welsh E-Science Center, > Cardiff University, UK > > Workshop Program Committee: > > P. Bellavista (Bologna University, Italy) > W. Binder (EPFL, Switzerland) > B. Benatallah (The University of New South Wales, Australia) > M. Dumas (Queensland University of Technology, Australia) > G. Dimarzo Serugendo (University of Geneva, Switzerland) > T. Finin (UMBC, USA) > S. Helal (University of Florida, USA) > A. Karageorgos (UMIST, United Kingdom) > G. Kouadri Mostéfaoui (University of Fribourg, Switzerland) > D. McMullen (Pervasive Technologies Lab, Indiana University, USA) > B. Michael (Siemens, Germany) > B. Medjahed (Virginia Polytechnic Institute & State University) > A. Messer (Samsung, USA) > A. Popovici (ETH Zurich, Switzerland) > A. Skarmeta (University of Murcia, Spain) > S. Tatesh (Lucent Technologies, UK) > M. Ulieru (University of Calgary, Canada) > C. Van Aart (University of Amsterdam, The Netherlands) > Q. Z. Sheng (The University of New South Wales, Australia) > > > Conference Location > > The workshop will be held at the Universidade Portucalense, Porto, > Portugal > > Registration Information > To attend the workshop you need to register at http://www.iceis.org > > Secretariat > ICEIS-2004 Secretariat - International Workshop on Ubiquitous Computing > IWUC'2004 > Universidade Portucalense > Departamento de Informática > Rua Dr. António Bernardino de Almeida, 541-619 > 4200 - 072 Porto - Portugal > Fax: +351 22 557 2015 > Tel: +351 22 557 2512 > E-mail: secretariat(a)iceis.org > Web site: http://www.iceis.org > > Soraya.Kouadri.M > -- > Kind regards | Maa salama | Meilleures salutations > > >

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