May 2003 - Haskell - Haskell.org

RE: list monad transformer
by Simon Peyton-Jones 16 May '03

16 May '03

We could do with someone to take ownership of the Control.Monad libraries. Andy Gill wrote them but I don't think he's actively maintaining them, which leaves discussions like this in mid air. Simon | -----Original Message----- | From: haskell-admin(a)haskell.org [mailto:haskell-admin@haskell.org] On Behalf Of Andrew J Bromage | Sent: 16 May 2003 05:20 | To: Iavor Diatchki | Cc: Haskell Mailing List; libraries(a)haskell.org | Subject: Re: list monad transformer | | G'day all. | | On Thu, May 15, 2003 at 11:12:32AM -0700, Iavor Diatchki wrote: | | > given that, we should either remove the | > #ListT# transformer from the monad library, or (perhaps better) put a | > big warning that it should only be used with commutative monads. | | My personal choice would be to dump it and replace it with Ralf | Hinze's backtracking monad transformer, which _does_ preserve | commutativity. If someone with checkin rights is listening in, | I'd be very happy to contribute my implementation, which is about | as stable as it's ever going to be. | | Cheers, | Andrew Bromage | _______________________________________________ | Haskell mailing list | Haskell(a)haskell.org | http://www.haskell.org/mailman/listinfo/haskell

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Source code for Intro to Functional Programming using Haskell?
by Ngai Lun Alan Liu 16 May '03

16 May '03

Hi, Just wondering if the code examples from Richard Bird's Introduction to Functional Programming using Haskell book are available online? If not, would he mind if I typed them up and put them online? Thanks, Alan

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list monad transformer
by Iavor Diatchki 15 May '03

15 May '03

hello, in his thesis [1], sheng liang mentions that we cannot define a list monad transformer. for some time now i was wondering why is that but never had the time to look into it, until the other day. what basically breaks is the associativity law, as the one form (#lhs# bellow) traverses the "choice tree" in a breadth first search manner, while the other (#rhs# bellow) does it in a depth first search manner. when the underlying monad is not commutative (i.e. the order of effects in it matters) we run into a probelm. here is an example: > import Control.Monad.List > > pr x = lift (putStr $ show x ++ " ") > > test :: (ListT IO (), ListT IO ()) > test = (m >>= f >>= g, m >>= \x -> f x >>= g) > where m = do pr "m: "; pr 1 `mplus` pr 2 > f _ = do pr "f: "; pr 3 `mplus` pr 4 > g _ = do pr "g: "; pr 5 `mplus` pr 6 > > main = do let (lhs,rhs) = test > runListT lhs > putStrLn "" > runListT rhs the transformer will work for commutative monads (intuition is above, formal proof is in [2]). given that, we should either remove the #ListT# transformer from the monad library, or (perhaps better) put a big warning that it should only be used with commutative monads. a rule of thumb for determining the commutativity of a monad is (using terminology from the library): the #Identity# monad is commutative the #ReaderT# transformer preserves commutativity the #ErrorT# transformer preserves commutativity the #WriterT# transformer preserves commutativity if its monoid (for collecitng output) is commutative bye iavor References ========== [1] Modular Monadic Semantics and Compilation. Sheng Liang. Ph.D. Thesis, Yale University, 1997. [2] Composing Monads. Mark P. Jones and Luc Duponcheel, Research Report YALEU/DCS/RR-1004, Yale University, New Haven, Connecticut, USA, December 1993.

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Announce: Hircules 0.1 IRC client released
by Jens Petersen 15 May '03

15 May '03

Hello, I am pleased to announce the first release of Hircules, an IRC client written in Haskell. It uses gtk2hs for the UI. The present code evolved from Lambdabot 1.0 by Andrew Bromage et al. (I hope it will be possible to factor out a nice IRC library from Lambdabot and Hircules, to avoid duplication of code and effort -- certainly I can see plenty of improvements that could be made in the structuring and code of Hircules.) Hircules is still quite basic in terms of features, and though I think it can be used for basic chatting, I would describe it as alpha quality software. It supports channel tabs, a raw irc tab and an all channel tab. It is also possible to use lambdabot extension modules, though by default most of them are disabled currently. The source code and rpms can now be downloaded from: http://haskell.org/hircules/ Give it a try if you can! Comments on the design, bug reports, rfe's, contributions, etc are most welcome. I hope to have a cvs repository up soon to make it more accessible. Cheers, Jens

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Function Name
by Uriel Dan Nudelman 15 May '03

15 May '03

Sorry for the question, there is a way to show function name? I need a function that receives a function and returns it's function name. Thanks. _________________________ Uriel Dan Nudelman MCP - .NET <http://www.vbnext.com> VBNext Developer <mailto:urieln@vbnext.com> urieln(a)vbnext.com

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Submission deadline Haskell Workshop 2003 approaching
by Johan Jeuring 15 May '03

15 May '03

The submission deadline for the Haskell Workshop 2003 is only a week away. ACM SIGPLAN 2003 Haskell Workshop Uppsala, Sweden, August 28, 2003 http://www.functional-programming.org/HaskellWorkshop/cfp03.html Call For Papers The Haskell Workshop forms part of the PLI 2003 colloquium on Principles, Logics, and Implementations of high-level programming languages, which comprises the ICFP and PPDP conferences as well as associated workshops. Previous Haskell Workshops have been held in La Jolla (1995), Amsterdam (1997), Paris (1999), Montreal (2000), Firenze (2001), and Pittsburgh (2002). ********************* Deadlines ********************* Deadline for submission: May 22, 2003 Notification of acceptance: June 23, 2003 Final submission due: July 3, 2003 Haskell Workshop: August 28, 2003 ********************* Topics ********************* The purpose of the Haskell Workshop is to discuss experience with Haskell, and possible future developments for the language. The scope of the workshop includes all aspects of the design, semantics, theory, application, implementation, and teaching of Haskell. Topics of interest include, but are not limited to, the following: Language Design with a focus on possible extensions and modifications of Haskell as well as critical discussions of the status quo; Theory in the form of a formal treatment of the semantics of the present language or future extensions, type systems, and foundations for program analysis and transformation; Implementation Techniques including program analysis and transformation, static and dynamic compilation for sequential, parallel, and distributed architectures, memory management as well as foreign function and component interfaces; Tool Support in the form of profilers, tracers, debuggers, pre-processors, and so forth; Applications, Practice, and Experience with Haskell for scientific and symbolic computing, database, multimedia and Web applications, and so forth as well as general experience with Haskell in education and industry; Functional Pearls being elegant, instructive examples of using Haskell. Following the scheme adopted by ICFP 2003, papers in the latter two categories need not necessarily report original research results; they may instead, for example, report practical experience that will be useful to others, re-usable programming idioms, or elegant new ways of approaching a problem. The key criterion for such a paper is that it makes a contribution from which other practitioners can benefit. It is not enough simply to describe a program! ********************* Submissions ********************* Authors should submit papers in postscript format, formatted for A4 paper, to Johan Jeuring johanj(a)cs.uu.nl by 22th May 2003. The length should be restricted to the equivalent of 5000 words (which is approximately 12 pages in ACM format). Accepted papers will be available in the form of a technical report of the Utrecht University or an equivalent format in time for the workshop. In addition, the papers will be published by the ACM and will appear in the ACM Digital Library. If there is sufficient demand, we will try to organise facilities for system demonstrations during lunch and coffee breaks. If you are interested in demonstrating an application or tool written in Haskell, please contact Johan Jeuring (johanj(a)cs.uu.nl) ********************* Programme Committee ********************* Magnus Carlsson OGI Olaf Chitil University of York Ralf Hinze University of Bonn Johan Jeuring (chair) Utrecht University Jan-Willem Maessen MIT Henrik Nilsson Yale University Simon Peyton Jones Microsoft Research Claus Reinke University of Kent

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Lectureships in Nottingham
by Graham Hutton 15 May '03

15 May '03

Dear all, We are currently seeking three new Lecturers (Assistant Professors) in Nottingham. There are no particular research areas specified for these positions, but applications in the area of the Foundations of Programming research group (www.cs.nott.ac.uk/Research/fop/) would be most welcome. The closing date for applications is Friday 30th May 2003. Graham Hutton ---------------------------------------------------------------------- THE UNIVERSITY OF NOTTINGHAM School of Computer Science & Information Technology Lecturers (Three posts) Applications are invited for the above posts in a rapidly-expanding School based at one of the UK's strongest research-led universities. The School was graded 5 in the 2001 Research Assessment Exercise. These posts are part of a steady increase in the size of the School, which was accompanied by a move to new purpose-built accommodation in September 1999. Although the successful candidates will have the opportunity of teaching within their specialist area at undergraduate and postgraduate level, there will also be a requirement to teach general computer science and information technology modules outside of any particular specialisation. Candidates should already have a PhD in computer science, or another closely related discipline, together with strong evidence of existing research work and the potential for future research at Grade 5 level. Outstanding candidates will be welcomed from any area of computer science. Salary will be within the range #22,191 - #33,679 per annum, depending on qualifications and experience. Informal enquiries may be addressed to Professor P H Ford, Head of School, tel: +44 (0)115 951 4251 or Email: Peter.Ford(a)Nottingham.ac.uk. Further information about the School is available on the WWW at: http://www.cs.nott.ac.uk. Further details and application forms are available from the Human Resources Department, Highfield House, The University of Nottingham, University Park, Nottingham, NG7 2RD. Tel: +44 (0)115 951 3263. Fax: +44 (0)115 951 5205. Please quote ref. RUB/539S. Closing date: 30 May 2003. +---------------------------------------------------------------------+ | Dr Graham Hutton Email : gmh(a)cs.nott.ac.uk | | School of Computer Science and IT Web : www.cs.nott.ac.uk/~gmh | | University of Nottingham | | Jubilee Campus, Wollaton Road | | Nottingham NG8 1BB Phone : +44 (0)115 951 4220 | | United Kingdom Fax : +44 (0)115 951 4254 | +---------------------------------------------------------------------+

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Announce: Hircules 0.1 IRC client released
by Jens Petersen 15 May '03

15 May '03

Hello, I am pleased to announce the first release of Hircules, an IRC client written in Haskell. It uses gtk2hs for the UI. The present code evolved from Lambdabot 1.0 by Andrew Bromage et al. (I hope it will be possible to factor out a nice IRC library from Lambdabot and Hircules, to avoid duplication of code and effort -- certainly I can see plenty of improvements that could be made in the structuring and code of Hircules.) Hircules is still quite basic in terms of features, and though I think it can be used for basic chatting, I would describe it as alpha quality software. It supports channel tabs, a raw irc tab and an all channel tab. It is also possible to use lambdabot extension modules, though by default most of them are disabled currently. The source code and rpms can now be downloaded from: http://haskell.org/hircules/ Give it a try if you can! Comments on the design, bug reports, rfe's, contributions, etc are most welcome. I hope to have a cvs repository up soon to make it more accessible. Cheers, Jens

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APLAS'03 : Asian Symposium on Programming Languages and Systems
by Manuel M T Chakravarty 14 May '03

14 May '03

Call for Papers (revised) The First Asian Symposium on Programming Languages and Systems (APLAS'03) http://www.jaist.ac.jp/aplas/ November 27-29, 2003 Beijing, China. (or Kanazawa, Japan or Nanjing, China. See below.) ---------------------------------------------------------------------- NOTICE ON THE SYMPOSIUM LOCATION AND NEW DATES While we plan to hold APLAS'03 in Beijing, there is a possibility of relocation due to SARS. If Beijing will be among the WHO's list of local transmission areas of SARS as of September 1, then the symposium will be moved to a city that is free of SARS risk and has airline connections from major cities that do not go through SARS affected cities. Our current candidate alternative cities are: Kanazawa, JAPAN and Nanjing, China. Safety is our priority in choosing the alternative. To accommodate the above situation, the symposium will be postponed by one month. The new important dates are: Submission deadline: June 20, 2003 Notification of acceptance: August 13, 2003 Final paper due: September 13, 2003 Symposium: November 27-29, 2003 ----------------------------------------------------------------------- DESCRIPTION APLAS aims at stimulating programming language research by providing a forum for the presentation of recent results and the exchange of ideas and experience in topics concerned with programming languages and systems. APLAS is based in Asia, but intends to be an international forum that serves the worldwide programming languages community. The APLAS series is sponsored by the Asian Association for Foundation of Software (AAFS), which has recently been founded by Asian researchers in cooperation with many researchers from Europe and the USA. APLAS has been discussed and prepared through informal workshops held in Singapore (2000), Daejeon (2001), and Shanghai (2002). APLAS03 will be the first formal symposium in the series. TOPICS The symposium is devoted to foundational issues in programming languages and systems, covering the following areas: * semantics and theoretical foundations * type systems and language design * compilers and implementation * program analysis and security * program transformation and calculation * concurrency INVITED SPEAKERS * Thomas A. Henzinger (University of California at Berkeley, USA) * Simon Peyton Jones (Microsoft Research, UK) * Wen-tsun Wu (Academia Sinica, China) GENERAL CHAIR Wei Li National Laboratory of Software Development Environment Beihang University Beijing, 100083, China E-mail: liwei(a)nlsde.buaa.edu.cn PROGRAM CHAIR Atsushi Ohori School of Information Science Japan Advanced Institute of Science and Technology Tatsunokuchi, Ishikawa, 923-1292 JAPAN E-mail: ohori(a)jaist.ac.jp Tel: +81 761 51-1275, Fax: +81 761 51-1149 PROGRAM COMMITTEE * Manuel Chakravarty (University of New South Wales, Australia) * Wei Ngan Chin (National University of Singapore, Singapore) * Tyng-Ruey Chuang (Academia Sinica, Taiwan) * Yuxi Fu (Shanghai Jiaotong University, China) * Masahito Hasegawa (Kyoto University, Japan) * Kohei Honda (Queen Mary College, UK) * Zhenjiang Hu (University of Tokyo, Japan) * Peter Lee (Carnegie Mellon University, USA) * Shilong Ma (Beijing University of Aeronautics and Astronautics, China) * Martin Odersky (Ecole Polytechnique de Lausanne, Switzerland) * Atsushi Ohori (JAIST, Japan), Chair * Don Sannella (University of Edinburgh, UK) * Zhong Shao (Yale University, USA) * Kwangkeun Yi (KAIST, Korea) * Taiichi Yuasa (Kyoto University, Japan) IMPORTANT DATES (NOTE THE CHANGES) Submission deadline: June 20, 2003 Notification of acceptance: August 13, 2003 Final paper due: September 13, 2003 Symposium: November 27-29, 2003 PROCEEDINGS AND SUBMISSION PROCEDURE The proceedings will be published in the Springer-Verlag Lecture Notes in Computer Science series. Final papers will be no more than 15 pages long in the format specified by Springer-Verlag. 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 must be submitted in either PDF format, or as PostScript documents that are interpretable by Ghostscript. The submission page will be open at http://www.jaist.ac.jp/aplas/submit/ before the deadline. Those who have difficulty in web-based submission should contact the program chair. It is recommended that submissions adhere to the format and length of the proceedings described above. Submissions that are clearly too long may be rejected immediately. SPONSORS Asian Association for Foundations of Software (AAFS) Beihang University.

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Haskell alterantives for Isabelle or ACL2
by Brian McBride 14 May '03

14 May '03

This is a newbie question. I'm interested in exploring the use of automatic theorem provers for helping with the formal specification of software systems (in my case semantics of languages and protocols). I've found ACL2 and Isabelle (and a few others) - the former uses Lisp as its meta langauge and the latter SML. For various reasons, some non-technical, I'd rather work in Haskell. Are there any systems similar to ACL2 or Isabelle that I should consider. Are there any alternative Haskell based approaches I should consider. Brian McBride HPLabs, Bristol

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