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Re: Class Multiplicity
by Ashley Yakeley 18 May '02

18 May '02

At 2002-05-18 00:41, Andrew J Bromage wrote: >Sometimes I think it would be handy if the Prelude used it more, >because then you could have full overloading for types which don't >quite play by the rules of the standard classes. For example: I do this sort of thing, see for instance: <http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/*checkout*/hbase/Source/Bas ic/Arithmetic.hs?rev=HEAD&content-type=text/plain> ...compiled with -fno-implicit-prelude -- Ashley Yakeley, Seattle WA

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CLPSE'02: Call for papers
by Dr. Gopal Gupta 17 May '02

17 May '02

[Apologies for multiple messages. Please note that the deadline is May 31, which is fast approaching.] CLPSE'02: (Constraint) Logic Programming and Software Engineering http://www.utdallas.edu/~gupta/clpse July 28, 2002 COPENHAGEN, DENMARK In Conjunction with Eighteenth International Conference on Logic Programming (Part of FLOC'02) http://floc02.diku.dk/ICLP/ The aim of this workshop is to explore applications of logic programming and constraint programming to the process of constructing reliable software and to programming-in-the-large. Papers and experience reports describing use of LP and CP techniques to various aspects of the software engineering process are invited. The workshop will be held on Saturday, July 28, 2002, in conjunction with 18th International Conference on Logic Programming in Copenhagen, Denmark (held Jul 29 - Aug 1) and is a continuation of the successful CLPSE'00 workshop held during CL2000 in London, England, in July 2000 (http://www.cs.nmsu.edu/~gupta/lpse2000) and CLPSE'01 workshop held during ICLP'01 in Paphos, Cyprus (http://www.cs.utdallas.edu/~gupta/clpse/clpse01.html) Topics of interest include (but are not limited to): o Rapid prototopying and System Modeling o Software Design Methodologies o Software Specification o Domain Specific Languages o Derivation of Efficient Implementations from Specifications o Automatic Software Generation o Testing and Debugging o Test Case Generation o Software Verification o Software Process Discovery o Software Reuse o Analysis of Software Systems/Software Process o Software Quality Assurance o Requirements Analysis o Security Issues Paper Submission deadline: May 31, 2002 Notification of acceptance/rejection: June 7th, 2002 Submission procedure: Electronically submit a postscript, pdf, or a word file to gupta(a)utdallas.edu. Papers should be a maximum of 15 pages. Proceedings will be made available during the workshop. Organizers: Gopal Gupta, University of Texas, Dallas, USA Kung-Ku Lau, Manchester University , UK Isidros Ramos, Universidad Politecnica de Valencia, Spain Roel Wuyts, University of Berne, Switzerland

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PADL'03: First Call for Papers
by Dr. Gopal Gupta 17 May '02

17 May '02

[- Apologies for multiple messages; - Paper submission deadline is July 31 - PADL'02 proceedings will be published as Springer Verlag LNCS, past proceedings can be found in LNCS 1551, 1753 and 1990, and 2257 ] FIRST CALL FOR PAPERS!!! Fifth International Symposium on Practical Aspects of Declarative Languages http://www.cs.utdallas.edu/~gupta/padl03 (PADL '03) New Orleans, Louisiana, USA Jan 13-14, 2002 Co-located with POPL 2003 Nothing is so practical as a good theory. Declarative languages build on sound theoretical bases to provide attractive frameworks for application development. Declarative approaches to programming include those based on logic, constraints, functions, and concurrency. Declarative languages have been successfully applied to a wide variety of real-world situations, ranging from database management to active networks to software engineering to decision support systems. New developments in theory and implementation have opened up new application areas. At the same time, applications of declarative languages to novel problems raise research issues. Questions include designing for scalability, language extensions for application deployment, and programming environments. Thus, applications drive the progress in the theory and implementation of declarative systems, and benefit from this progress as well. PADL provides a forum for researchers, practitioners, and implementors of declarative languages to exchange ideas on application areas and on the requirements for effective deployment of declarative systems. We invite papers dealing with practical applications of logic, constraint, functional, and concurrent programming. The scope of PADL includes, but is not limited to: o Innovative applications of declarative languages o Declarative domain-specific languages and applications o New developments in declarative languages and their impact on applications o Practical experiences o Novel uses of declarative languages in the classroom o Evaluation of implementation techniques on practical applications o Application letters (Applets) - see below o Declarative pearls - see below Papers should highlight the practical contribution of the work and the relevance of declarative languages to achieve that end. PADL 2003 will co-locate with ACM POPL 2003, in New Orleans. Application Letters (Applets) Real-world users of declarative languages may be so fully occupied writing declarative programs that they lack the time to write a full paper describing their work. Conference attendees often hear only from those developing declarative languages --- the users are too busy using them. In order to attract greater participation from users, the conference solicits application letters describing experience using declarative languages to solve real-world problems. Such papers might be half the length of a full paper (though any length up to a full paper is fine), and may be judged by interest of the application and novel use of declarative languages as opposed to a crisp new research result. Declarative Pearls Program committees traditionally expect a paper to make a contribution of a certain size. Ideas that are small, rounded, and glow with their own light may have a number of venues, but conferences are not typically among them. (Among the outlets have been columns such as Bentley's Programming Pearls in Communications of the ACM, Rem's Small Programming Exercises in Science of Computer Programming, and Barendregt's Theoretical Pearls and Bird's Functional Pearls in the Journal of Functional Programming.) The conference invites papers that develop a short declarative program. Such papers might be half the length of a full paper (though any length up to a full paper is fine), and may be judged by elegance of development and clarity of expression as opposed to a crisp new research result. Important Dates: o Paper Submission: Jul. 31, 2002 o Notification: Oct. 2, 2002 o Camera Ready: Nov. 6, 2002 o Symposium: Jan. 13-14, 2003 Paper Submission: Authors should submit a 100-200 word abstract and a full paper, written in English. Submissions should be no more than 15 pages in standard Springer-Verlag LNCS format: 122mm x 193mm in 10 point font, Computer Modern Roman or similar. Submissions that do not meet these guidelines may not be considered. Style files for Latex and Word are provided by Springer-Verlag. Papers should be submitted in PDF format, and be printable on both USLetter and A4 paper; details of web submission will be posted later. If this requirement is a hardship, please contact the program chairs. Each submission should include, on its first page, the paper title; authors and their affiliations; contact author's email and postal addresses, telephone and fax numbers; and a 100-200 word abstract. The abstract will be used to assist us in selecting appropriate reviewers for the paper. Submitted papers should have content that has not previously been published in other conferences or refereed venues, and simultaneous submission to other conferences or refereed venues is unacceptable. Each paper should explain its contributions in both general and technical terms, clearly identifying what has been accomplished, saying why it is significant, and comparing it with previous work. Authors should strive to make the technical content of their papers understandable to a broad audience. Program Committee: o Lennart Augustsson, Sandburst, USA o Phillipe Blache, CNRS & Universite de Provence, France o Veronica Dahl, Simon Fraser University, Canada (PROGRAM CO-CHAIR) o Ines Dutra, Universidade Federal do Rio de Janeiro, Brazil o Kathleen Fisher, AT&T Labs, USA o Matthew Flatt, University of Utah, USA o Juliana Freire, Bell Laboratories, USA o Matteo Frigo, Massachusetts Institute of Technology, USA o Terry Gaasterland, Argonne National Laboratory and University of Chicago, USA o Alejandro Garcia, Universidad Nacional del Sur, Argentina o Manuel Hermenegildo, Universidad Politecnica de Madrid, Spain o John Hughes, Goteborg University, Sweden o Neil Jones, University of Copenhagen, Denmark o Shriram Krishnamurthi, Brown University, USA o Naoki Kobayashi, Tokyo Institute of Technology, Japan o George Necula, University of California at Berkeley, USA o Luis Moniz, Pereira Universidade Nova de Lisboa, Portugal o Paul Tarau, BinNet Corporation and University of North Texas, USA o Philip Wadler, Avaya Labs, USA (PROGRAM CO-CHAIR) o David S. Warren, State University of New York at Stony Brook, USA For more Information, please contact Philip Wadler Avaya Labs wadler(a)avaya.com 233 Mount Airy Road, room 2C05 http://www.research.avayalabs.com/user/wadler/ Basking Ridge, NJ 07920 USA office: +1 908 696 5137 fax: +1 908 696 5402 Organizer: Gopal Gupta (University of Texas at Dallas) Sponsored by: Compulog Americas, Association for Logic Programming

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I need to know
by matush23＠netscape.net 17 May '02

17 May '02

Hi. Im a new haskell user, I know there are library about graphs, but i need to know all the info about, where I can download this library, and what can i do with it, and how can I use it. Thanks. __________________________________________________________________ Your favorite stores, helpful shopping tools and great gift ideas. Experience the convenience of buying online with Shop@Netscape! http://shopnow.netscape.com/ Get your own FREE, personal Netscape Mail account today at http://webmail.netscape.com/

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Re: Dependent Types
by dominic.j.steinitz＠britishairways.com 17 May '02

17 May '02

Robin, Thanks very much for this. My problem turned out to be tripping over the monomorphism restriction. When I looked at this it looked like a candidate for dependent types but as you point out you can solve this just as well in Haskell 98. You save a set of brackets with my approach! Dominic. Jon Fairbairn <Jon.Fairbairn(a)cl.cam.ac.uk>@haskell.org on 16/05/2002 16:45:28 Sent by: haskell-admin(a)haskell.org To: "Dominic Steinitz" <dominic.j.steinitz cc: haskell bcc: Subject: Re: Dependent Types "Dominic Steinitz" <dominic.j.steinitz(a)britishairways.com> wrote: > I've managed to crack something that always annoyed me when I used to do > network programming. [. . .] > > Suppose I want to send an ICMP packet. The first byte is the type and the > second byte is the code. Furthermore, the code depends on the type. Now you > know at compile time that you can't use codes for one type with a different > type. However, in Pascal (which is what I used to use) you only seemed to > be > able to carry out run time checks. I'm not sure I understand your problem. I don't see what's wrong with the following approach, which is Haskell 98. The type byte is coded as the type of the packet. Excuse the perhaps ideosyncratic style ... (in particular, I'm expecting people to use import qualified with this). module ICMP where data Type = Redirect RedirectData | TimeExceeded TimeData {- so you get an alternative for each of the packet types -} instance Enum Type where fromEnum (Redirect _) = 5 fromEnum (TimeExceeded _) = 11 {- we can't derive Enum for ICMP.Type, because it has non-nullary constructors. That just makes it a bit more tedious One could provide a class "code" with code:: t -> Int instead of fromEnum -} {- now we define individual record types for each of the different ICMP types -} data RedirectData = RedirectData {redirectCode:: RedirectCode, ip_addr:: Int, -- whatever redirectData:: [Int]} -- or whatever data RedirectCode = RedirNet | RedirHost | RedirNetToS | RedirHostToS deriving Enum data TimeData = TimeData {timeCode:: TimeExceededCode, timeData:: [Int]} -- or whatever data TimeExceededCode = ExcTTL | ExcFragTime deriving Enum {- Since Haskell 98 doesn't have MPTCs, if we want to encode packets as anything other than [Int] we'd have to define more classes. Encode serves as an example. -} class Encode t where encode:: t -> [Int] instance Encode Type where encode p@(Redirect d) = fromEnum p: encode d encode p@(TimeExceeded d) = fromEnum p: encode d instance Encode RedirectData where encode d = fromEnum (redirectCode d): ip_addr d: redirectData d instance Encode TimeData where encode d = fromEnum (timeCode d): 0: timeData d so one can go encode (Redirect (RedirectData RedirNet 0 [0])) and get [5,0,0,0], but encode (TimeExceeded (TimeData RedirNet 0 [0])) gives an error, as one would hope. What am I missing? Cheers, Jón -- Jón Fairbairn Jon.Fairbairn(a)cl.cam.ac.uk 31 Chalmers Road jf(a)cl.cam.ac.uk Cambridge CB1 3SZ +44 1223 570179 (after 14:00 only, please!) _______________________________________________ Haskell mailing list Haskell(a)haskell.org http://www.haskell.org/mailman/listinfo/haskell ------------------------------------------------------------------------------------------------- Save time by using an eTicket and our Self-Service Check-in Kiosks. For more information go to http://www.britishairways.com/eservice1

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Call for papers for the SSGRR 2002s. Conference in L`Aquila near Rome,Italy (Jul 29 - Aug 4 2002.)
by ssgrr2002s＠rti7020.etf.bg.ac.yu 17 May '02

17 May '02

Dear Dr. Haskell, I have been appointed to serve as the General Chair of the Summer 2002 edition of the SSGRR series of international conferences. The SSGRR-2002S (Summer) conference on "Infrastructure for e-Business, e-Education, e-Science, and e-Medicine" takes place in SSGRR (Scuola Superiore G. Reiss Romoli), the delux congress and educational center of the Telecom Italia Group of companies. Programming-related papers (C,C++,JAVA,etc...) are of special interest for this conference, and your contributions are welcome! This is in L'Aquila near Rome, Italy, from July 29 (Monday) at 5pm (start of the Grand Opening) till August 4 (Sunday) at 10am (departure of busses to the Rome airport Fiumicino and the railway station Tiburtina). Most of the past participants beleive that this was one of the most interesting, most useful, and definitely THE most hospitable conference they ever attended. The SSGRR-2002S will be open by Jerome Friedman from MIT (laureate of the NOBEL PRIZE) and Travor Gruen-Kennedy of Citrix (listed by some sources as one of the world's TOP-25 contributors to the development of the Internet). For details, see the WWW site of the conference (www.ssgrr.it/en/ssgrr2002s/index.htm) Among other things, this WWW site also includes the full-blown version of the invitation letter-contract, with all relevant details (www.ssgrr.it/en/ssgrr2002s/invitation.htm) The soft deadline for you to decide if you are coming is May 25, 2002 (in the worst case you should respond before May 31th). By that date the place for you is unconditionally reserved. After that date, you will be accepted to the conference only if the existing 240 places are not filled. Before May 25, 2002, please send only the following: (a) TITLE, (b) AUTHORS, (c) AFFILIATION, (d) ABSTRACT, and (e) STATEMENT THAT YOU WILL COME 100% (answers like "maybe" will be treated as NO answer from you). The full paper is due on June 20, 2002. The early registration price for the 6-day stay at SSGRR is EURO1200 (if you represent an institution) or EURO1440 (if you come as an individual). Coming without a paper costs you extra EURO600 or EURO720, respectively. Deadline for the early registration is June 30, 2002. If you come with an accompanying person, the early registration extra cost is EURO300, for 6 days of bed and breakfast, in an external hotel (please note that the best external hotels are 4-star, and not nearly as comfortable as the accommodation in the SSGRR complex). The SSGRR complex includes only single-bed rooms, and therefore available only to those who come without an accompanying person. If you have any questions, please check the WWW site of the conference and especially the part entitled FAQ(Frequently Asked Questions). If you still have questions or there is something that we can do for you, please write to Organizing Committee at ssgrr2002s(a)rti7020.etf.bg.ac.yu (preferred) or if absolutely necessary, to myself directly (vm(a)etf.bg.ac.yu) Sincerely yours, Professor V. M. Milutinovic, General Chair of the SSGRR-2002S (galeb.etf.bg.ac.yu/~vm/) P.S. No matter if you will attend the SSGRR-2002S conference or not, please let us know if you like to be invited to the Winter edition of the year 2003 (SSGRR-2003W) to be held in the same place from January 6, 2003 at 5pm till January 12, 2003 at 10am. Shall we reinvite you? Of course, if you wish not to receive again information about the SSGRR conferences, please let us know, and we will remove your name from our list. IMPORTANT DETAILS: 1. Your presentation is 25 minutes, plus 5 minutes for discussion and the change of speakers. 2. The author of the LAST paper in the session is the session chairman, so he/she is motivated to respect the timing. The slots of the non-show-up papers are to be used for extra discussions. Moving of presentation slots is NOT permitted. 3. Timing of the session is given on the WWW site of the conference. 4. Special sessions are dedicated to advanced programming, 5. More information on the SSGRR center is given on the WWW site of the conference. 6. Transportation related information, on July 29 from Tiburtina station in Rome to SSGRR in L'Aquila, and on August 4 from L'Aquila to Tiburtina station and Fiumicino airport is given in the conference WWW site (pay attention to FAQ). 7. Details of the food schedule, social program, and all other relevant details are also given on the WWW site of the conference.

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RE: Negative literals and the meaning of case -2 of -2 -> True
by Simon Marlow 17 May '02

17 May '02

> To find out how Haskell implementations treat negated > literals, I tested > the following program: > > ------------------------------------------------ > main = print (minusTwo,trueOrFalse) > > minusTwo = -2::N > > trueOrFalse = > case minusTwo of > -2 -> True > _ -> False > > data N = Negate N | FromInteger Integer deriving (Eq,Show) > > instance Num N where > negate = Negate > fromInteger = FromInteger > ------------------------------------------------- > > The result is: > > * ghc 5.02.2: main outputs: (FromInteger (-2),True) GHC has two bugs in this area, one of which has been fixed recently. The current output is (Negate (FromInteger 2),False) (i.e. the same as hbc). We were being a little too eager to replace 'negate (fromInteger N)' by 'fromInteger (-N)'. There is also a bug in the pattern handling, however. Thanks for a nice test case... Cheers, Simon

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Positions Available
by N Ghani 17 May '02

17 May '02

There are a number of people interested in FP at the University of Leicester, so maybe we can increase that number ... -------------------------------------------------------------------- UNIVERSITY OF LEICESTER DEPARTMENT OF MATHEMATICS AND COMPUTER SCIENCE The Department of Mathematics and Computer Science invites applications for five positions in Computer Science. One position is at the professorial level and the others are lectureships, which are at a similar level to assistant professor positions in North America. The Department is divided into three groups: Computer Science, Pure Mathematics and Applied Mathematics. The current research interests of the Computer Science group are in Logic, Algorithms & Complexity, Theory of Distributed & Reactive Systems and Semantics. The appointments are intended to diversify and strengthen the Computer Science group with regards to both teaching and research. The successful applicants will be ambitious, able to develop their own research within a multi-faceted environment, and have a strong research record and potential. This is a superb opportunity for persons of energy, drive and ambition to assume rewarding roles and to establish themselves in a young, dynamic and rapidly developing department. Information about all aspects of the Department is available from its web pages [http://www.mcs.le.ac.uk] /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ CHAIR IN COMPUTER SCIENCE (Ref: P9044) We are looking for a person of drive and enthusiasm to create a leading research group. Candidates whose research interests are complementary to the existing research groups are particularly encouraged to apply. Nevertheless, applications are welcomed from individuals with an outstanding research record in any area of Computer Science. The appointment will commence on a date to be agreed. The salary will be within the professorial range. Further particulars are available from: Personnel Office (Professorial Appointments), University of Leicester, University Road, Leicester, LE1 7RH, U.K. Tel: (+44) (0)116 252 2422, Fax: (+44) (0)116 252 5140, email: pt31(a)le.ac.uk, web: www.le.ac.uk/personnel/jobs. Candidates should submit one unbound copy of their application to the Personnel Office (Professorial Appointments). Closing date: 21st June 2002 /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ LECTURERS A/B IN COMPUTER SCIENCE (Ref: A5485) 20,470 to 32,537 pounds pa (March 2002 pay scales) Available from 1st September 2002 LECTURER A IN COMPUTER SCIENCE (Ref: A5504) 20,470 to 24,435 pounds pa (March 2002 pay scales) Available for 2 years from 1st September 2002 Applications are invited for three lectureships (to start 1st September 2002 or as soon as possible thereafter) and a two-year lectureship in Computer Science (to start 1st September 2002). There is no restriction regarding the area of research and applicants with expertise in any area of Computer Science are welcomed. Application forms and further particulars are available (by quoting the reference) from Personnel Office, University of Leicester, University Road, Leicester, LE1 7RH, U.K. Tel: (+44) (0)116 252 5114, Fax: (+44) (0)116 252 5140, email: jobs(a)le.ac.uk, web: www.le.ac.uk/personnel/jobs. Closing date: 10th June 2002 /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ Candidates who are interested in any of these positions are invited, if they so wish, to contact either of: Prof Rajeev Raman Professor Rick Thomas, Head of Computer Science Head of Department, telephone (+44) (0)116 252 3894 telephone (+44) (0)116 252 3885 email rr29(a)mcs.le.ac.uk e-mail rmt(a)mcs.le.ac.uk who will be pleased to discuss the positions further.

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How to get functional software engineering experience?
by Jeffrey Palmer 17 May '02

17 May '02

Hello all, I've got a not-quite-so-technically-detailed question for everyone. For the past ten or so years, I've been building relatively large "real-world" software systems, and I've always been interested in finding new and innovative ways to reduce complexity and improve system maintainability. I was recently seduced by functional programming, and I'm now VERY interested in applying a functional software engineering approach to a real project. However, it appears that the only place (short of Ericsson) I can actually work on a complex functional system is in academia. Unfortunately, this is not an option, as I have no Ph.D., and going back to school is probably not realistic. Are there any options for people like me, or does my functional experience remain limited to the hobby* work I can squeeze in at night and on weekends? Thoughts? - j * I'm building a realistic image synthesis package in Haskell, if anyone's interested. ;) -- The river is moving. The blackbird must be flying.

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RE: ASSIST ME
by Konst Sushenko 17 May '02

17 May '02

(the original confidential business proposal removed) Hello, It was my impression that the list maintainers were considering making this list moderated, or open only to subscribers. Is there a decision on that? Thanks konst

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