May 2002 - Haskell - Haskell.org

GRIN as a backend
by Hal Daume III 12 May '02

12 May '02

There was talk a couple of years ago about attaching the GRIN backend to the GHC frontend; I was wondering if anything became of this, or if any other high-performance graph reduction algorithms have been implemented to the point of usability... - Hal -- Hal Daume III "Computer science is no more about computers | hdaume(a)isi.edu than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume

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SoSyM - New Intl. Journal on Software & System Modeling
by Bernhard Rumpe 12 May '02

12 May '02

*********************************************************************** * New International Journal * * Software and System Modeling (SoSyM) *********************************************************************** The new quarterly Springer journal titled Software and System Modeling (SoSyM) will be launched in Fall of 2002. Information about the journal and a call for papers can be found on the website: http://www.sosym.org SoSyM is a quarterly international journal that focuses on theoretical and practical issues pertaining to the development and application of software and system modeling languages and techniques. The aim of the journal is to publish high-quality works that further understanding of the theoretical underpinnings of modeling languages and techniques, present rigorous analyses of modeling experiences, and present scalable modeling techniques and processes that facilitate high-quality and economical development of software. We invite authors to submit papers that discuss and analyze concerns and experiences pertaining to software and system modeling languages, techniques, tools, practices and other facets. The following are some of the topic areas that are of interest: Methodological issues Development of modeling standards Formal syntax and semantics of modeling languages such as the UML Rigorous model-based analysis Model-based testing techniques Model composition and transformation Metamodeling techniques Measuring quality of models Generating test and code artifacts from models Case studies and experience reports with significant lessons learned Comparative analyses of modeling languages and techniques Scientific assessment of modeling practices The submission process is continuously open. Details can be found at: http://www.sosym.org and http://link.springer.de/link/service/journals/10270/index.htm You may subscribe to our regular announcements (e.g. about new issues) by sending an email to sosym-announcement-subscribe(a)yahoogroups.com Editors-in-Chief: Robert France Colorado State University Fort Collins, Colorado, USA E-mail: france(a)cs.colostate.edu Bernhard Rumpe Munich University of Technology Munich, Germany E-mail: rumpe(a)in.tum.de Editorial Board: Scott W. Ambler (Canada) Egidio Astesiano (Italy) Jean Bézivin (France) James M. Bieman (USA) Grady Booch (USA) Lionel Briand (Canada) Ed Brinksma (Netherlands) Manfred Broy (Germany) Jean-Michel Bruel (France) Jaelson F.B. Castro (Brazil) Betty H.C. Cheng (USA) Tony Clark (UK) Steve Cook (UK) Desmond DŽSouza (USA) Gregor Engels (Germany) Andy Evans (UK) David Garlan (USA) Martin Gogolla (Germany) David Harel (Israel) Constance L. Heitmeyer (USA) Brian Henderson-Sellers (Australia) Heinrich Hussmann (Germany) Michael Jackson (UK) Ivar Jacobson (USA) Jean-Marc Jezequel (France) Stuart Kent (UK) Cris Kobryn (USA) Ingolf Krüger (USA) Kevin Lano (UK) Gary T. Leavens (USA) Pierre-Alain Muller (France) A. Jefferson Offutt (USA) Wolfgang Reisig (Germany) August-Wilhelm Scheer (Germany) Bran V. Selic (Canada) Perdita Stevens (UK) Jos Warmer (Netherlands) Roel W. Wieringa (Netherlands) Alan Cameron Wills (UK) Jim Woodcock (UK) PS: We apologize if you received this email more than once.

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Re: SUGGESTION: haskell-announce mailing list
by Ashley Yakeley 11 May '02

11 May '02

At 2002-05-10 10:38, C.Reinke wrote: >existing split, this ought to be split off the haskell list (i.e., >everyone subscribed to haskell would initially be subscribed to >haskell and to haskell-announce). > >Opinions? Suggestions? I suggest that all posts to haskell-announce are copied to haskell. Perhaps even the haskell list should itself be subscribed to haskell-announce. And of course then initially no-one should be subscribed to haskell-announce. Furthermore haskell-announce should be moderated, so all posts to it are screened before distribution. This seems to be the standard way of doing things for announce/discussion list pairs. This way people only need to be subscribed to one of them, and there's no chance of missing announcements just because you're only subscribed to one list. -- Ashley Yakeley, Seattle WA

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SUGGESTION: haskell-announce mailing list
by C.Reinke 10 May '02

10 May '02

Several contributors to the HC&A Report reported the same problem with the current setup of Haskell mailing lists: In spite of the split into haskell and haskell-cafe, they missed the general calls for contributions on haskell(a)haskell.org because some of them, being involved in other work as well, only browse the flood of traffic. When the list was originally split into haskell (for announcements and discussion starters) and haskell-cafe (for longer discussions), some of us suggested a separate haskell-announce instead (or indeed, support for client-based filtering instead of this server-based split). In my own setup, postings to haskell and haskell-cafe still go into a single folder, and I separate out announcements and similar things by hand (because I usually don't have the time to follow them up immediately, and because there's no reliable pattern to use for automatic filtering; e.g., this very email I'd filter out into the TODO area, even though it's not strictly speaking an announcement). Even though many discussions move quickly to haskell-cafe, which some of us are no longer subscribed to, the discussion starters and the more technical discussions still seem to generate enough traffic that some Haskellers miss announcements made on haskell. Based on this recent negative experience, I suggest to introduce a separate haskell-announce mailing list. To avoid upsetting the existing split, this ought to be split off the haskell list (i.e., everyone subscribed to haskell would initially be subscribed to haskell and to haskell-announce). Opinions? Suggestions? Cheers, Claus

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Re: ANNOUNCE: Haddock version 0.2, a Haskell documentation tool
by Ashley Yakeley 10 May '02

10 May '02

At 2002-05-09 09:44, Simon Marlow wrote: >I'm pleased to announce version 0.2 of Haddock, a documentation >generation tool for Haskell source code. It's available from > > http://www.haskell.org/haddock/ It's at <http://www.haskell.org/haddock/haddock-0.2-src.tar.gz>. -- Ashley Yakeley, Seattle WA

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Re: updating labelled fields
by Zdenek Dvorak 09 May '02

09 May '02

Hello. >I like this idea, but I think it will cause ambiguity in >parsing. Consider: > >blah = do {foo} ... > >should foo be parsed as a statement list (under the assumption that the >open brace is instead of using layout) or as an assignment, as in: > >blah = do {foo} > x <- bar > >(which probably wouldn't typecheck, but we don't know that at parsing.) i >could be wrong and it might be able to be made work, but i'm not >convinced... I don't think this is ambigous -- do is a keyword, so no record field update can be assumed after it. Zdenek _________________________________________________________________ Chat with friends online, try MSN Messenger: http://messenger.msn.com

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ANNOUNCE: Haddock version 0.2, a Haskell documentation tool
by Simon Marlow 09 May '02

09 May '02

I'm pleased to announce version 0.2 of Haddock, a documentation generation tool for Haskell source code. It's available from http://www.haskell.org/haddock/ The changes relative to version 0.1 are listed here: http://www.haskell.org/haddock/CHANGES.txt Cheers, Simon

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Summer School on Generic Programming: early reg deadline 17th May
by Jeremy Gibbons 09 May '02

09 May '02

A reminder: the early registration deadline for the Summer School on Generic Programming is Friday 17th May. Jeremy * Summer School and Workshop on Generic Programming St Anne's College, Oxford, UK 26th to 30th August 2002 In conjunction with Summer School and Workshop on Advanced Functional Programming This school is a successor to the Summer School and Workshop on Algebraic and Coalgebraic Methods in the Mathematics of Program Construction, held in Oxford in April 2000 and with lecture notes shortly to appear as LNCS 2297. For this school we have recruited an excellent group of lecturers on generic programming, that is, the construction of programs that work on different datatypes and yet may exploit the structure of that data. ************ Lecturers ************ * Roland Backhouse (University of Nottingham): A Generic Theory of Datatypes * Peter Buneman (University of Edinburgh): Semi-Structured Data * Roy Crole (University of Leicester): Categories and Types * Jose Luiz Fiadeiro (University of Lisbon and ATX Software): Theory and Practice of Software Architecture * Ralf Hinze (University of Bonn) and Johan Jeuring (University of Utrecht): Generic Haskell * Martin Odersky (Ecole Polytechnique Federale de Lausanne): Object-Oriented and Functional Approaches to Compositional Programming ************ Deadlines ************ For registration with an early-bird discount: 17th May 2002 For late registration: 12th July 2002 ************ Organizers ************ Roland Backhouse (University of Nottingham) Jeremy Gibbons (University of Oxford) ************ Further information ************ Web: http://www.comlab.ox.ac.uk/oucl/research/areas/ap/ssgp/info.html PDF poster: http://www.comlab.ox.ac.uk/oucl/research/areas/ap/ssgp/ssgp-poster.pdf Email: ssgp-info(a)comlab.ox.ac.uk Post: SSGP, c/o Jane Ellory, Oxford University Computing Laboratory, Wolfson Building, Parks Road, Oxford OX1 3QD, United Kingdom. Fax: +44 1865 273839; mark "fao SSGP (Jane Ellory)"

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by sales137＠163.com 09 May '02

09 May '02

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RE: duplicate instance declarations
by Simon Peyton-Jones 09 May '02

09 May '02

Two instances are duplicates if their 'head' (the part after the =>) is identical, modulo alpha renaming. Even with overlapping instances allowed, GHC never makes an arbitrary choice between two instance decls. It choses one over the other only if its head is more specific (i.e. a substitution instance). This will never happen in the case of duplicate instance decls, so GHC rejects duplicates up front. GHC's resolution of overlapping instances does not use backtracking, so it is quite weak. For example instance C a => X a where ... instance D a => X a where ... You might think that if a type T is an instance of C but not D, then it would be clear which of these two instances to use to resolve the constraint (X T), but GHC does not spot that. It uses only the instance head. I hope this clarifies a bit. Simon | -----Original Message----- | From: Hal Daume III [mailto:hdaume@ISI.EDU] | Sent: 03 May 2002 18:33 | To: C T McBride | Cc: Haskell Mailing List | Subject: Re: duplicate instance declarations | | | Cool, thanks, that made sense. | | > [lots of stuff snipped] | | What's the difference, then, between "duplicate instances" | and "overlapping" instances? It seems that even with | -fallow-overlapping-instances and even | -fallow-undecidable-instances ghc still rejects the code I had. | | _______________________________________________ | Haskell mailing list | Haskell(a)haskell.org http://www.haskell.org/mailman/listinfo/haskell |

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