- Haskell - Haskell.org

Call for Contributions - HC&A Report (November 2003 edition)
by C.Reinke 20 Oct '03

20 Oct '03

Dear Haskellers, once again, we set out to get an overview of what is going on in all things Haskell, and *you* are invited to help with this effort! Please contribute to the forthcoming fifth edition of our ================================================================ Haskell Communities & Activities Report http://www.haskell.org/communities/ Submission deadline: 31 October 2003 (please send your contributions to me, in plain-ASCII or LaTeX format, keeping "HC&A Report" in the subject line) ================================================================ The Haskell Communities & Activities Reports are a bi-annual, birds-eye overview of Haskell development over the last 6 months, and perhaps an outlook over concrete plans for the next 6 months. If you have only recently joined the Haskell world, have a look through the May 2003 edition - it provides a useful overview, starting points and links that may answer many a FAQ. The current plan is to get contributions in by the end of October, and to get the collective report out early next month (you will find this an excellent opportunity to update your webpages, get out pending releases, announce new projects, summarize recent developments in sub-communities for all Haskellers, etc. ;-). The general idea is to update all existing summaries (these reports are really about *recent/current* activities), to drop any topics that haven't had any activity for two consecutive 6-month periods, and to add any new developments or topics for which no-one contributed summaries to the previous edition, while trying to keep the whole from blowing up (last time, we ended up with about 30 pages). Looking forward to your contributions, Claus (current editor) -- Haskell Communities and Activities Report (November 2003 edition) All contributions are due in by the end of October 2003! http://www.haskell.org/communities/ --------------------------------- topics New suggestions for current hot topics, activities, projects, .. are welcome - especially with names and addresses of potential contacts, but here is a non-exclusive list of likely topics (see also http://www.haskell.org/communities/topics.html ): General Haskell developments; Haskell implementations; Haskell extensions; Standardization and documentation; Haskell tutorials, how-tos and wikis; Organisation of Haskell tool and library development; Haskell-related projects and publications; new research, fancy tools, lonq-awaited libraries, cool applications; Feedback from specialist mailing lists to the Haskell community as a whole; Haskell announcements; .. all (recent) things Haskell Announcements: if you've announced anything new on the Haskell list over the last six months, you'll want to make sure that is reflected in this edition! Project pings: if you're maintaining a Haskell tool/library/.., you'll want to let everyone know that it is still alive and actively maintained, even if there may have been no new additions (and even more so if there have been new developments). Tutorials: if you've fought with some previously undocumented corner of Haskell, and have been kind enough to write down how you did manage to build that networking program, or if you've written a tutorial about some useful programming techniques/patterns, this is your opportunity to spread the word (btw, short, topic-specific, and hands-on tutorials that only show how to achieve a certain practical task would do a lot to make things easier for new Haskellers - Erlang and Perl folks seem to be good at this kind of thing, but why not have a similar effort for Haskell?) Applications: if you've been working quietly, using Haskell for some interesting project or application (commercial or otherwise), you might want to let others know about what you're using Haskell for, and about your experiences using the existing tools and libraries; are you using Haskell on your job? There was an interesting thread about using Haskell for non-Haskell things not too long ago - why not write a sentence or two about your use of Haskell for our report? Feedback: if you're on one of the many specialist Haskell mailing lists, you'll want to report on whatever progress has been made there (GUI API discussions, library organisation, etc.) If you're unsure whether a contact for your area of work has come forward yet, have a look at the report's potential topics page, or get in touch with me. I've contacted last time's contributors, hoping they will volunteer to provide updates of their reports, and will update the contacts on the topics page fairly regularly. But where you don't yet see contacts listed for your own subject of interest, you are very welcome to volunteer, or to remind your local community/project team/mailing list/research group/etc. that they really ought to get their act together and let the Haskell community as a whole know about what they've been doing!-) --------------------------------- what should I write? That depends on your topic, but as a general rule, it shouldn't take you long. A simple sentence or two about your use of Haskell could go into the "Individual Haskellers and their projects" section. If you're a company, or if you're working on a project using Haskell as the implementation language, a paragraph on that could go into the "Commercial Applications" and "Non-Commercial Applications" sections. A typical summary report about a tool/library/project/application/.. would be between 1 and 3 paragraphs of ASCII text (what's it about? major topics and results since the last report? current hot topics? major goals for the next six months?) plus pointers to material for further reading (typically to a home page, or to mailing list archives, specifications and drafts, implementations, meetings, minutes,..). For those who prefer templates to fill in, the report is edited in LaTeX, and an entry template might look something like this: \subsubsection{<MYSTUFF>} \report{<MY NAME}\\ <WHAT IS IT?> <WHAT IS ITS STATUS? / WHAT HAS HAPPENED SINCE LAST TIME?> <CAN OTHERS GET IT?> <WHAT ARE THE IMMEDIATE PLANS?> \FurtherReading \url{<PROJECT URL>} Browsing through previous editions should give you a good idea of the variety of possibilities, ranging from very brief to extensive.

1 0

HaRe 0.1 updates, and ghc-6.0.1
by C.Reinke 20 Oct '03

20 Oct '03

Since releasing version 0.1 of the Haskell Refactorer HaRe, we've continued to update the HaRe snapshots on our webpage every now and then, in response to your feedback and bug reports. http://www.cs.kent.ac.uk/projects/refactor-fp/hare.html We do not usually announce every new snapshot here, but there have been several requests for making HaRe build with ghc-6.0.1, and, since last week, the snapshots include the necessary workarounds. Apart from several smaller things, the current snapshot (20/10/2003) also includes a fix for one rather substantial bug in introNewDef and generaliseDef; String and Char literals should also no longer cause problems (see README.txt). So, if this has been keeping you from playing with HaRe, you might want to check again (and please keep those experience/bug reports and suggestions coming!-). Happy Refactoring! The HaRe Team (Huiqing Li, Claus Reinke, Simon Thompson)

1 0

hscairo 0.3
by Abraham Egnor 20 Oct '03

20 Oct '03

The haskell bindings for cairo have reached 0.3, which is enough of a milestone to warrant this post, I think. Main improvements include: * better (i.e. more Haskellish) wrappers for the Matrix functions * better status handling - status is now checked automatically, and errors reported properly. * Attributes are parameterized by object type as well as value type. What this means is that things other than the implicit Cairo object can have Attributes; for example, Matrix objects have an "affine" Attribute. * all current cairo functions wrapped. A few had been left out of the prior version due to implementation difficulty. * a better backend. Specifically, a running hscairo program no longer uses up all CPU time. The new version is available at http://ofb.net/~abe/hscairo-0.3.tar.bz2. Abe

1 0

how to do lazy IO like getContents?
by Ben Escoto 19 Oct '03

19 Oct '03

Hi, I'm trying to do IO and it isn't lazy enough. My problem seems similar to this one: Write a function that lazily reads characters from stdin, just like getContents does. These two don't work: lazyRead :: IO String lazyRead = do first_char <- getChar rest <- lazyRead return $ first_char:rest lazyRead2 :: IO String lazyRead2 = (liftM2 (:)) getChar lazyRead2 because neither has the intended behavior, because if I type: lazyRead >>= putChar . head Then it seems that all of stdin is read, not just the first character, which is different from: getContents >>= putChar . head which only reads one character. So how do you write getContents in haskell? Thanks for any insight. -- Ben Escoto

3 5

calling FunPtr's?
by John Meacham 17 Oct '03

17 Oct '03

I need to call some dynamically linked routines recieved via Posix.DynamicLinker but am unsure how to do this from haskell. I do not know the types of the functions I wish to call at compile time so can't create appropriate foreign import statements. What would be nice is something like callFunPtr :: (Storable a, Storable b) => FunPtr z -> a -> IO b with a being a tuple if I want to push multiple arguments onto the stack perhaps. this function should be straightforward to implement, as it just needs to place the arguments on the stack in the appropriate fashion and pull the return value of out the proper register or memory location, but would obviously be very architecture specific so should be provided by the compiler. does something like this exist? is there another way to do this? John -- --------------------------------------------------------------------------- John Meacham - California Institute of Technology, Alum. - john(a)foo.net ---------------------------------------------------------------------------

2 2

Announce: buddha 1.0 released
by Bernard James POPE 17 Oct '03

17 Oct '03

Announcing buddha version 1.0 ----------------------------- www.cs.mu.oz.au/~bjpop/buddha A declarative debugger for Haskell 98. It is based on program transformation and works with GHC 5 and 6. buddha offers a declarative debugging algorithm and a browsing mechanism. It is useful for finding logical errors in programs and for exploring computations in a high-level manner. The interface is designed to be simple to use, and may be an ideal aid for teaching Haskell. Version 1.0 is known to work on unix platforms, including OS X, GNU/linux and freeBSD. It does not work on Windows. buddha is released under the GPL license. Enjoy, Bernie.

3 3

forkIO implemenation
by Feingold, Jason (WingspanTech) 17 Oct '03

17 Oct '03

I infer from a discussion from March 2002 that concurrency in Haskell is not implemented in native threads, at least in Windows. Is this true? The discussion also implies that an implementation is in the works. The reason I ask is that when I forkIO and accept from a socket in the new thread everything seems blocked. Is this the expected behavior? It would be really nice to be able to listen on multiple sockets in a single process. Thanks, Jason Feingold

2 1

How do I derive a type class for different type parameters?
by Ben_Yu＠asc.aon.com 16 Oct '03

16 Oct '03

Hi there, I'm having a problem with type classes. I have a class called PrettyPrintable, For data type: data Generic a = ...... I need to provide instance of Generic a for type class PrettyPrintable. The parameter type a could be either PrettyPrintable or Show. If I write the following, it won't compile: instance Show a => PrettyPrintable (Generic a) where ...... instance PrettyPrintable a => PrettyPrintable (Generic a) where ... How do I achieve this? Another alternative that I think may work is if I can say "all Show a will be PrettyPrintable a in terms of this implementation". But it seems that the following code won't compile either: instance Show a => PrettyPrintable a where ...... Am I doing the design totally wrong? Or there is actually some clever scheme in Haskell that can do this elegantly? Thanks. Ben. This message is intended only for the addressee and may contain information that is confidential or privileged. Unauthorized use is strictly prohibited and may be unlawful. If you are not the intended recipient, or the person responsible for delivering to the intended recipient, you should not read, copy, disclose or otherwise use this message, except for the purpose of delivery to the addressee. If you have received this email in error, please delete and advise us immediately.

1 0

Final call: Formal Methods for Components and Objects
by M.M. Bonsangue 16 Oct '03

16 Oct '03

(We apologize for the reception of multiple copies) ********************LAST CALL FOR PARTICIPATION ********************** Second International Symposium on Formal Methods for Components and Objects (FMCO 2003) DATES 4 - 7 November 2003 PLACE Lorentz Center, Leiden University, Leiden, The Netherlands REGISTRATION FORM http://fmco.liacs.nl/fmco03.html REGISTRATION FEES 400 euro for regular participants and 275 euro for students FINAL PROGRAM TUESDAY 4th, November 2003 8:45 - 9:00 Welcome 9:00 - 10:00 Keynote: David Parnas (University of Limerick, IE) Mathematical Documentation of Software 10:00 - 10:30 Break 10:30 - 11:15 Razvan Diaconescu (IMAR, RO) Behavioural specification for hierarchical object composition 11:15 - 12:00 Heike Wehrheim (University of Oldenburg, DE) Preserving Properties under Change 12:00 - 13:30 Lunch break 13:30 - 14:30 Keynote: Andrew D. Gordon (Microsoft Research, UK) Formal Tools for Securing Web Services 14:30 - 15:00 Break 15:00 - 15:45 Jeannette Wing (Carnegie Mellon University, USA) Vulnerability Analysis Using Attack Graphs 15:45 - 16:30 Yassine Lakhnech (University of Grenoble, FR) Security protocols, their modes and analysis: a survey 16:30 - 16:45 Break 16:45 - 17:30 Albert Benveniste (IRISA/INRIA - Rennes, FR) Heterogeneous reactive systems formal modeling WEDNESDAY 5th, November 2003 9:00 - 10:00 Keynote: Tony Hoare (Microsoft Research Cambridge, UK) The Verifying Compiler: a Grand Challenge for Computing Research 10:00 - 10:30 Break 10:30 - 11:15 Willem-Paul de Roever (University of Kiel, DE) Data Refinement: model-oriented proof methods and their comparison 11:15 - 12:00 Frank de Boer (CWI, Amsterdam, NL) Hoare Logics for Object-Oriented Programming: State of the Art 12:00 - 13:30 Lunch break 13:30 - 14:15 Jean-Marc Jezequel (IRISA, Rennes, FR) Model-Driven Engineering: Basic Principles and Open Problems 14:15 - 15:00 Jan Friso Groote (Eindhoven University, NL) Visualisation of HUGE state spaces 17:00 - 19:15 Social Event 19:30 - Dinner THURSDAY 6th, November 2003 9:00 - 10:00 Keynote: Yuri Gurevich (Microsoft Research Redmond, USA) The Semantics of AsmL 10:00 - 10:30 Break 10:30 - 11:15 Egon Boerger (Pisa University, IT) Exploiting the "A" in Abstract State Machines for Specification Reuse. A Java/C# Case Study. 11:15 - 12:00 Werner Damm (University of Oldenburg, DE) t.b.a. 12:00 - 13:30 Lunch break 13:30 - 14:30 Keynote: Joseph Sifakis (Verimag, FR) Component-based construction of deadlock-free systems 14:30 - 15:00 Break 15:00 - 15:45 Philippe Schnoebelen (CNRS, Cachan, FR) The Verification of Lossy Channel Systems 15:45 - 16:30 Bengt Jonsson (Uppsala University, SE) t.b.a. 16:30 - 16:45 Break 16:45 - 17:30 Jan Rutten (CWI, Amsterdam, NL) A case study in coinductive stream calculus: signal flow graphs for dummies FRIDAY 7th, November 2003 9:00 - 10:00 Keynote: E. Allen Emerson (University of Texas, USA) Model checking many components 10:00 - 10:30 Break 10:30 - 11:15 Amir Pnueli (The Weizmann Institute of Science, ISR) t.b.a. 11:15 - 12:00 Natalia Sidorova (Eindhoven University, NL) Practical approaches for the verification of asynchronous components: model checking, abstraction and static analysis 12:00 - 13:30 Lunch break 13:30 - 14:30 Keynote: Desmond D'Souza (Kinetium, Austin, USA) Component Architectures - Some meeting points of practice, trend, and theory 14:30 - 15:00 Break 15:00 - 15:45 Jose Luiz Fiadeiro (University of Leicester, UK) CommUnity on the move: architectures for distribution and mobility 15:45 - 16:30 Gregor Engels (University of Paderborn, DE) Consistent interaction of components 16:30 - 17:15 Rob van Ommering (Philips Research Laboratories, NL) Component Based Architectures and Formalization MOBI-J AFFILIATED WORKSHOP On Monday 3rd, November 2003 from 13:30 till 17:00 there will at the Lorentz Center be a half-day Mobi-J workshop on "Assertional Methods for Java and its Extension with Mobile Asynchronous Channels". REGISTRATION Participation is limited to about 80 people, using a first-in first-served policy. To register, please fill in the registration form at http://fmco.liacs.nl/fmco03.html. The registration fee is 400 euro for regular participants and 275 euro for students It includes the participation to the symposium, a copy of the proceedings, all lunches and refreshments, and a social event (with dinner). ORGANIZING COMMITTEE F.S. de Boer (CWI and Utrecht University) M.M. Bonsangue (LIACS-Leiden University) S. Graf (Verimag) W.P. de Roever (CAU) For more information about participation and registration see the FMCO site above or consult either F.S. de Boer (frb(a)cwi.nl) or M.M. Bonsangue (marcello(a)liacs.nl)

1 0

RTA'04: call for papers
by Femke van Raamsdonk 16 Oct '03

16 Oct '03

****************************** * * * RTA'04 CALL FOR PAPERS * * * ****************************** http://www-i2.informatik.rwth-aachen.de/RTA04/ The 15th Int. Conf. on Rewriting Techniques and Applications (RTA'04) will be part of the Federated Conference on Rewriting, Deduction and Programming (RDP'04). IMPORTANT DATES: Jan 15 2004: Deadline electronic submission of title+short abstract Jan 22 2004: Deadline electronic submission of papers Mar 14 2004: Notification of acceptance of papers Apr 4 2004: Deadline for final versions of accepted papers Jun 3-5 2004: Conference. RTA is the major forum for the presentation of research on all aspects of rewriting. Typical areas of interest include (but are not limited to): * APPLICATIONS: case studies; rule-based (functional and logic) programming; symbolic and algebraic computation; theorem proving; system synthesis and verification; proof checking. * FOUNDATIONS: matching and unification; narrowing; completion techniques; strategies; constraint solving; explicit substitutions; tree automata. * FRAMEWORKS: string, term, and graph rewriting; lambda-calculus and higher-order rewriting; proof nets; constrained rewriting/deduction; categorical and infinitary rewriting. * IMPLEMENTATION: compilation techniques; parallel execution; rewriting tools. * SEMANTICS: equational logic; rewriting logic. INVITED TALKS will be given at RTA'04 by: * Neil Jones (Copenhagen) * Aart Middeldorp (Innsbruck) * Robin Milner (Cambridge) BEST PAPER AWARDS: A 1000 Euro award wil be given to the best paper or papers as decided by the PC. The award may also totally or partially go to the best paper with a student as main author, according to the submission letter. RTA'04 PROGRAM COMMITEE: * Zena Ariola (Oregon) * J�rgen Giesl (Aachen) * Masahito Hasegawa (Kyoto) * H�l�ne Kirchner (Nancy) * Pierre Lescanne (Lyon) * Klaus Madlener (Kaiserslautern) * Narciso Mart�-Oliet (Madrid) * Paul-Andr� Melli�s (Paris) * Oege de Moor (Oxford) * Vincent van Oostrom (Utrecht, Chair) * Frank Pfenning (Carnegie Mellon) * Ashish Tiwari (SRI) * Ralf Treinen (ENS Cachan) * Roel de Vrijer (Amsterdam) RTA'04 SUBMISSIONS: Submissions must be original and not submitted for publication elsewhere. Submission categories include regular research papers and system descriptions. Also problem sets and submissions decribing interesting applications of rewriting techniques will be very welcome. As usual, accepted papers will appear in the Springer-Verlag Lecture Notes in Computer Science series. More information about paper submission will be available at the RDP'04 web page <http://www-i2.informatik.rwth-aachen.de/RDP04/> For further questions please contact the program chair: RTA'04 PROGRAM CHAIR: Vincent van Oostrom Universiteit Utrecht Department of Philosophy Heidelberglaan 8 3584 CS Utrecht, Netherlands Vincent.vanOostrom(a)phil.uu.nl

1 0