April 2004 - Haskell - Haskell.org

dependent types, type class contexts
by John D. Barnett 07 Apr '04

07 Apr '04

Hello- I'm interested in simulating dependent types in haskell, with the aim of operating on (as Oleg put it) "stanamically" sized lists: types reflect size constraints, but ultimately need to be resolved from dynamic input. I have a good handle on how to do this (read on), but I keep running into the same problems related to managing type class contexts. Ultimately, I think what I might want is a way of _excluding_ types from classes, or declaring classes closed. Much of this is a rehash of what others have presented; sorry if I don't give appropriate credit (Oleg, Okasaki, Hallgren, ...) Here's what I want to cover: - types/classes parallel algebraic data types - rank-2 polymorphic continuation to simulate dependent types - stanamically sized lists - (ditto) as a numeric type - contexts ?#$%#!!! - exclusion as a possible solution? The first part is familiar, and is exemplified in "Fun with Functional Dependencies"; this is the parallel between types/classes and algebraic data types. Just as we can define a type with values (and an example function on that type): > data Nat = Zero | Succ Nat > toInt :: Nat -> Int > toInt Zero = 0 > toInt (Succ x) = 1 + toInt x We can have a corresponding definition for a class and types: > class NatT a where > toIntT :: a -> Int > data ZeroT > instance NatT ZeroT where > toIntT ZeroT = 0 > data SuccT a > instance (NatT a) => NatT (SuccT a) where > toIntT (SuccT x) = 1 + toIntT x (Although functional dependencies can be used to essentially define functions/relations at the type level, I don't make use of that here.) So far so good. But what if I want to dynamically convert from Nat to NatT? I'd like a function defined as: < convert Zero = ZeroT < convert (Succ x) = SuccT (convert x) But this isn't legitmate; the return type depends on the input value. So first, we need an existential type to capture the return value: > data Nat' = forall a . NatT a > convert :: Nat -> Nat' A dependent return value isn't allowed, but we can use a rank-2 polymorphic continuation to simulate it: > convert x = convert_ x Nat' > convert_ :: Nat -> (forall a . NatT a => a -> b) -> b > convert_ Zero k = k ZeroT > convert_ (Succ x) k = convert_ x (\x' -> k (SuccT x')) By the way, although I've seen a few of you use this trick, is there proven theory to back this up-- that rank-2 polymorphism can simulate any function with a dependent type by using CPS? This brings me to lists; I'm actually playing around with nested datatypes (a la Okasaki's square matrices), but this suffices to make the connection: > class ListT a where > map0 :: b -> a b > map1 :: (b -> c) -> a b -> a c > map2 :: (b -> c -> d) -> a b -> a c -> a d > toList :: a b -> [b] > data NilT b = NilT > instance ListT NilT where > map0 _ = NilT > map1 _ _ = NilT > map2 _ _ _ = NilT > toList _ = [] > data ConsT a b = ConsT b (a b) > instance (ListT a) => ListT (ConsT a) where > map0 x = ConsT x (map0 x) > map1 f (ConsT x xs) = ConsT (f x) (map1 f xs) > map2 f (ConsT x xs) (ConsT y ys) = ConsT (f x y) (map2 f xs ys) > toList (ConsT x xs) = x:(toList xs) So, for instance, we can have a list (ConsT 1 (ConsT 2 (ConsT 3 NilT)))::((ConsT (ConsT (ConsT NilT))) Int) i.e., a list of length 3. Again, dynamic conversion can be supported by an existential type and polymorphic recursion (CPS): > data List' b = forall a . ListT a => List' (a b) > fromList' :: [b] -> List' b > fromList' l = fromList_ l List' > fromList_ :: [b] -> (forall a . ListT a => a b -> c) -> c > fromList_ [] k = k (NilT) > fromList_ (x:xs) k = fromList_ xs (\xs' -> ConsT x xs') Thus, (fromList' [1,2,3]) should yield the existential version of the list above. It's probably worth mentioning that I define another class method, fromList:: (ListT a) => [b] -> Maybe (a b), which only succeeds if the input is the correct length. This allows me to write two versions of a function: static and dynamic, as: > myZip :: (ListT a) => (a b) -> (a c) -> (a (b,c)) > myZip = map2 (,) > myZip' :: [b] -> [c] -> Maybe (List' (b,c)) > myZip' x y = do (List' x') <- return $ fromList' x -- convert, unwrap > y' <- fromList y > result <- myZip x' y' > return (List' result) Type inference forces x' and y' to have the same type; this determines at which type fromList is applied, which succeeds or fails depending on the size of the input. I've swept some details under the rug-- see what you need to do to make appropriate instances of Show, Eq. This becomes more relevant in trying to make a Num instance, so I can have automagically derived vector operations. Here's my goal: > instance (ListT a, Num b) => Num (a b) where > (+) = map2 (+) > (-) = map2 (-) > (*) = map2 (*) > negate = map1 negate > abs = map1 abs > signum = map1 signum > fromInteger = map0 . fromInteger This is where things start to get tricky. In order for the above to type-check (in ghc 6.2; I understand handling contexts may vary), I need to add (Show (a b), Eq (a b)) to the context. What I've elided is that I have already provided declarations > instance (ListT a, Eq b) => Eq (a b) > instance (ListT a, Show b) => Show (a b) which requires -fallow-overlapping-instances, as e.g., Eq (a b) overlaps with [b]. As I get deeper into the numeric type heirarchy, the contexts required become increasingly cumbersome; these ultimately make the existential type List' useless for any numeric types, and instead require me to use (IMHO) overly specified existential types. This gets at the crux of my questions: - Why can't the compiler tell that (ListT a, Num b) is enough to figure out the additional context it seems to need? - Would it be possible to _exclude_ a type from a class, to aviod overlapping instances? Perhaps what I want is negation in a type class declaration: < forall a . a /= [] => class ListT a Alternatively, I'd like to state that the _only_ instances of ListT are NilT and ConsT. Are there definitive references on context resolution (aside from the compiler source, which I have not looked at)? Has anyone grappled with these problems and come up with satisfactory solutions? Thanks for your help, and I'm happy to go into more detail. I tried to be brief, but, well, I didn't succeed. -John Barnett

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RE: [Haskell] deriving with newtypes
by Simon Peyton-Jones 06 Apr '04

06 Apr '04

Your word is my command. 'Tis done. Simon | -----Original Message----- | From: haskell-bounces(a)haskell.org [mailto:haskell-bounces@haskell.org] On Behalf Of Wolfgang | Jeltsch | Sent: 21 March 2004 17:55 | To: The Haskell Mailing List | Subject: [Haskell] deriving with newtypes | | Hello, | | I'm trying to use GHC's deriving mechanism for newtypes in the following way: | class C a b | instance C [a] Char | newtype T = T Char deriving C [a] | Unfortunately, this isn't possible. Is there a reason for this? Can I | circumvent this restriction? | | Wolfgang | | _______________________________________________ | Haskell mailing list | Haskell(a)haskell.org | http://www.haskell.org/mailman/listinfo/haskell

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Foclasa: Last Call for Papers
by Jean-Marie JACQUET 06 Apr '04

06 Apr '04

[ Our apologies for multiple copies. ] ====================================================================== 3nd International Workshop on Foundations of Coordination Languages and Software Architectures (Foclasa 2004) August 30, 2004, London, United Kingdom Workshop affiliated to CONCUR'2004, August 30 - September 3 2004. ====================================================================== SCOPE AND TOPICS Modern information systems rely more and more on combining concurrent, distributed, mobile and heterogenous components. This move from old systems, typically conceived in isolation, induces the need for new languages and software architectures. In particular, coordination languages have been proposed to cleanly separate computational aspects and communication. On the other hand, software architects face the problem of specifying and reasoning on non-functional requirements. All these issues are widely perceived as fundamental to improve software productivity, enhance maintainability, advocate modularity, promote reusability, and lead to systems more tractable and more amenable to verification and global analysis. The aim of the workshop is to bring together researchers working on the foundations of component-based computing, coordination, and software architectures. Topics of interest include (but are not limited to): o Theoretical models for coordination (component composition, concurrency, dynamic aspects of coordination, semantics, expressiveness); o Specification, refinement, and analysis of software archi- tectures (patterns and styles, verification of functional and non-functional properties); o Coordination, architectural, and interface description languages (implementation, interoperability, heterogeneity); o Agent-oriented languages (formal models for interacting agents); o Dynamic software architectures (mobile agents, configuration, reconfiguration); o Modeling of information systems (groupware, internet and the web, workflow management, CSCW and multimedia applications) o Coordination patterns (mobile computing, internet computing); o Tools and environments for the development of coordinated applications o Methodologies for validating and certifying software compositions SUBMISSION GUIDELINES Papers describing original work are solicited as contributions to Foclasa. Submitted papers should be limited to 6 000 words, preferrably formatted according to the Electronical Notes in Theoretical Computer Science. They should be emailed as PostScript (PS) or Portable Document Format (PDF) files to jmj(a)info.fundp.ac.be. PUBLICATION Following the previous edition, the proceedings will be published as a volume of the Electronical Notes in Theoretical Computer Science. IMPORTANT DATES: o June 5, 2004: Submission deadline. o July 15, 2004: Notification of acceptance. o August 15, 2004: Final version. o August 30, 2004: Meeting Date. LOCATION The workshop will be held in London in August 30 2004. It is a satellite workshop of CONCUR 2004. For venue and registration, see the CONCUR web page at http://www.doc.ic.ac.uk/concur2004/. WORKSHOP ORGANIZERS o Antonio Brogi (University of Pisa, Italy) o Jean-Marie Jacquet (University of Namur, Belgium) o Ernesto Pimentel (University of Malaga, Spain) PROGRAMME COMITTEE (provisional): o Farhad Arbab (CWI, The Netherlands) o Antonio Brogi (University of Pisa, Italy) - Co-chair o Manfred Broy (University of Munich, Germany) o Jean-Marie Jacquet (University of Namur, Belgium) - Co-chair o Joost Kok (University of Leiden, The Netherlands) o Antonia Lopes (University of Lisbon, Portugal) o Ronaldo Menezes (Florida Institute of Technology, USA) o Ernesto Pimentel (University of Malaga, Spain) - Co-chair o Sebastian Uchitel (Imperial College, United Kingdom) o Mirko Viroli (University of Bologna, Italy) o Jan Vitek (Purdue University, USA)

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ANNOUNCE: Haskell XML Toolbox Version 4.00
by Uwe Schmidt 06 Apr '04

06 Apr '04

Haskell XML Toolbox 4.00 I would like to announce a new version of the Haskell XML Toolbox for processing XML including a validating parser and a new XPath module. new features: * compiles with ghc version 6.2 * new module structure for input modules to ease porting to other OS/compilers * new example programs More information and download: http://www.fh-wedel.de/~si/HXmlToolbox/index.html Please email comments, bugs, etc. to hxmltoolbox(a)fh-wedel.de Uwe Schmidt <uwe(a)fh-wedel.de> -- University of Applied Sciences, Wedel, Germany http://www.fh-wedel.de/~si/index.html

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Final Cfp: 8th Intnl. Workshop CIA 2004 on Cooperative Information Agents
by Matthias Klusch 05 Apr '04

05 Apr '04

++ Apologies for multiple copies due to cross-posting ++ Final Call for Papers: ________________________________________________ Eighth International Workshop CIA-2004 on Cooperative Information Agents September 27 - 29, 2004 Fair and Congress Center, Erfurt, Germany In co-operation with ACM SIGART and ACM SIGWeb http://www.dfki.de/~klusch/cia2004 ________________________________________________ CIA 2004 is co-sponsored by AgentLink III, EU FP6 Coordinated Action tranSIT GmbH, Germany Whitestein Technologies, Switzerland Spanish Association for Artificial Intelligence (AEPIA), Spain URJC Decision Engineering Lab (DMR), Spain CIA 2004 is co-located with 2nd German Conference on Multiagent Systems Technologies (MATES 2004) 4th International Multi-Conference Net.Object Days (NOD 2004) IMPORTANT DATES =============== Deadline for Paper Submission: April 19, 2004 Notification of Authors: June 14, 2004 Camera-Ready Paper: July 5, 2004 INVITED TALKS OF EXCELLENCE =========================== * Agent-Based Distributed Data Mining: Current Pleasures, and Future Directions by Hillol Kargupta (University of Maryland at Baltimore County, USA) * Information Agents and Semantic Web Services: Perspectives, Technologies, and Applications by Terry Payne (University of Southampton, UK) * Scenarios of Information Agents in Digital Cities: Description and Simulation by Toru Ishida (University of Kyoto, Japan) THEME & TOPICS ============== Information agent technology is one of the major key technologies for the Internet and worldwide Web. An information agent is a computational software entity that has access to one or multiple, heterogeneous and distributed information sources, pro-actively searches for and maintains relevant information on behalf of its human users or other agents preferably just-in-time. In other words, it is managing and overcoming the difficulties associated with information overload in the open and exponentially growing Internet and Web. One key challenge of developing advanced information systems is to balance the autonomy of networked data and knowledge sources with the potential payoff of leveraging them by the appropriate use of intelligent information agents. Therefore, the special focus of this workshop series is on the perspectives, design, and implementation of intelligent information agents which are able to collaborate in open, networked data and information environments for and providing added value to a variety of applications in different domains. Keeping with its tradition all topics in the research area of intelligent and collaborating information agents are covered by the CIA 2004 workshop. Topics are (but not limited to) * Systems and Applications of Information Agents - Architectures of information agents. - Prototypes and fielded systems of information agents. - Recommender systems; collaborative cases. - Issues of programming information agents. * Advanced Theories of Collaboration - Social filtering, cooperative search, group forming, negotiation, etc. - Cooperation in real-time and open environments. - Self-organising information agent systems. - Capability-based mediation between information agents. - Collaboration in peer-to-peer networks. * Agent-Based Knowledge Discovery - Knowledge discovery by (systems of) information agents; collaborative cases. - Agent-based distributed data mining. - Distributed information retrieval and Web mining. * Information Agents for the Semantic Web - Agent-based service discovery and composition. - Agent-based service matchmaking and brokering in the Semantic Web. - Agent-based distributed ontology learning. * Mobile Information Agents - Mobile information agents for distributed information retrieval. - Engineering mobile information agents. - Cooperative mobile information agents. * Information Agents for Ubiquitous Computing Environments - Information agents for pervasive computing: Visions, applications, surveys; collaborative cases. * Rational Information Agents for E-Business - Models of economic rationality and trust. - Issues of privacy of communication, data security, and jurisdiction for agent-mediated trading. - Coalition and team formation algorithms. * Intelligent Interfaces for Information Agents - Human-agent interaction for (systems of) information agents. - Life-like characters and avatars. - Information agents for/applied to digital cities. - Advanced, personalized 3-d visualizations of information spaces. - Agent-based Web usage mining - Personalisation; collaborative cases. * Adaptive Information Agents - Adaptive information retrieval; collaborative cases. - Reasoning with imperfect information: collaborative cases. - Multi-strategy and meta-learning for cooperative information agents. Proceedings =========== The proceedings of the CIA workshop series are published as volumes in the Springer series of Lecture Notes on Artificial Intelligence (CIA-1997: LNAI 1202, CIA-1998: LNAI 1435, CIA-1999: LNAI 1652, CIA-2000: LNAI 1860, CIA-2001: LNAI 2182, CIA-2002: LNAI 2446, CIA-2003: LNAI 2782). The proceedings of the workshop will be available to the participants at the workshop. Preparation & Submission of Papers ================================== For preparation of (camera-ready) papers to be submitted please follow the instructions for authors available at the Springer LNCS Web page: http://www.springer.de/comp/lncs/authors.html For those not using the Springer LNCS style files: The paper must be formatted in A4 size using 10 point Times. (If Times is not available, please use one of the similar fonts widely used in phototypesetting.) Printing area should be 12.2 x 19.3 cm, and the interline distance should be arranged in such a way that some 42 to 45 lines occur on a full-text page. The length of each paper should not exceed 15 pages. All papers must be written in English. Papers not conforming to the above requirements may be rejected without review. Submissions will be reviewed for quality, correctness, originality and relevance. Submission of full paper including all figures and references is either in POSTSCRIPT or PDF format only. In any case, please check whether the file is really printable on a postscript-level-2 printer before submitting it. You may submit your paper either online, or by email, or by postal mail. * Online Paper Submission: Online submission is a three-step process: Step 1. Complete the electronic summary submission form http://platon.escet.urjc.es/conf-tool/cgi-bin/cia2004/submit You will need to provide: Corresponding author details; Title, authors, and keywords of the submission; Abstract text of the submission Step 2. Save the tracking number and authorization code for your submission obtained upon completion of the summary form Step 3. Upload your paper submission, in either PDF or gzipped PostScript format, using your tracking number and authorization code, at http://platon.escet.urjc.es/conf-tool/cgi-bin/cia2004/uploadpaper Tracking number and authorization code allow you to revise the summary form information and to upload modified versions of your submission. Please use the tracking number in all future correspondence about your paper. Many thanks in advance for your efforts! * Paper Submission by E-Mail or Postal Mail: Alternatively, you may submit your paper via o E-Mail to klusch(a)dfki.de. Compressed (zipped) files only. o Postal Mail: send 3 hard copies (unstapled) of your paper to the following mail address: Dr. Matthias Klusch, DFKI GmbH, Stuhlsatzenhausweg 3, 66123 Saarbruecken, Germany AWARDS ====== The CIA 2004 workshop issues a BEST PAPER AWARD, and a SYSTEM INNOVATION AWARD to acknowledge highly innovative research and development, respectively, in the area of intelligent information agents. For more information please visit http://www.dfki.de/~klusch/cia2004/html/awards.html Organisation ============ Workshop Chair Matthias Klusch (DFKI, Germany) Program Co-Chairs Sascha Ossowski (University Rey Juan Carlos, Spain) Vipul Kashyap (United States National Library of Medicine, USA) Local Organising Co-Chair Rainer Unland (University of Duisburg-Essen, Germany) Program Committee Elisabeth Andre (University of Augsburg, Germany) Wolfgang Benn (TU Chemnitz, Germany) Monique Calisti (Whitestein Technologies, Switzerland) Brahim Chaib-draa (Laval University, Canada) Yves Demazeau (Leibniz, France) Frank Dignum (University of Utrecht, The Netherlands) Tharam Dillon (La Trobe University, Australia) Boi Faltings (EPFL, Switzerland) Fausto Giunchiglia (University of Trento, Italy) Rune Gustavsson (Blekinge TH, Sweden) Heikki Helin (TeliaSonera AB, Sweden/Finland) Mike Huhns (University of South Carolina, USA) Toru Ishida (University of Kyoto, Japan) Catholijn Jonker (Free University of Amsterdam, Netherlands) Hillol Kargupta (UMBC, USA) Manolis Koubarakis (Technical University of Crete, Greece) Daniel Kudenko (University of York, UK) Victor Lesser (University of Massachusetts, USA) Beatriz Lopez (University of Girona, Spain) Mike Luck (University of Southampton, UK) Pablo Noriega (IIIA CSIC, Spain) Werner Nutt (Heriot-Watt University Edinburgh, UK) Eugenio Oliveira (University of Porto, Portugal) Andrea Omicini (University of Bologna, Italy) George Papadopoulos (University of Cyprus, Cyprus) Michal Pechoucek (TU Prague, Czech Republic) Paolo Petta (Austrian Research Institute for AI, Austria) Alun Preece (University of Aberdeen, UK) Volker Roth (Fraunhofer IGD, Germany) Claudio Sartori (University of Bologna, Italy) Ken Satoh (National Institute of Informatics, Japan) Heiko Schuldt (UMIT Innsbruck, Austria) Onn Shehory (IBM Research, Israel) Von-Wun Soo (National Tsing Hua University, Taiwan) Steven Willmott (UPC Barcelona, Spain) Mike Wooldridge (University of Liverpool, UK) Makoto Yokoo (NTT Communication, Japan) Franco Zambonelli (University of Modena, Italy) Ning Zhong (Maebashi Institute of Technology, Japan)

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RE: [Haskell] deriving with newtypes
by Simon Peyton-Jones 02 Apr '04

02 Apr '04

Not for a while: 6.4. Meanwhile, you'll need to build from source or grab a development snapshot build S | -----Original Message----- | From: haskell-bounces(a)haskell.org [mailto:haskell-bounces@haskell.org] On Behalf Of Wolfgang | Jeltsch | Sent: 02 April 2004 17:53 | To: The Haskell Mailing List | Subject: Re: [Haskell] deriving with newtypes | | Am Freitag, 2. April 2004 18:49 schrieben Sie: | > Your word is my command. 'Tis done. | > | > Simon | | Thank you very much. In which GHC release will this be available? | | Wolfgang | | > | -----Original Message----- | > | From: haskell-bounces(a)haskell.org [mailto:haskell-bounces@haskell.org] | > | > On Behalf Of Wolfgang | > | > | Jeltsch | > | Sent: 21 March 2004 17:55 | > | To: The Haskell Mailing List | > | Subject: [Haskell] deriving with newtypes | > | | > | Hello, | > | | > | I'm trying to use GHC's deriving mechanism for newtypes in the | > | > following way: | > | class C a b | > | instance C [a] Char | > | newtype T = T Char deriving C [a] | > | Unfortunately, this isn't possible. Is there a reason for this? Can I | > | circumvent this restriction? | > | | > | Wolfgang | > | | > | _______________________________________________ | > | Haskell mailing list | > | Haskell(a)haskell.org | > | http://www.haskell.org/mailman/listinfo/haskell | | _______________________________________________ | Haskell mailing list | Haskell(a)haskell.org | http://www.haskell.org/mailman/listinfo/haskell

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Announce: wxHaskell 0.7
by Daan Leijen 02 Apr '04

02 Apr '04

Announcement: wxHaskell version 0.7 ---------------------------------------------------------------------- <http://wxhaskell.sourceforge.net> This new release contains bug fixes, a few new widget attributes, and has an improved build system for MacOS X and Linux. Binary installers are provided for MacOS X, Linux (RPM), and Windows. The webpage has some nice screenshots now of larger applications that are written with wxHaskell, and a sample of wxHaskell with HOpenGL. There is also a Wiki site for wxHaskell now. All the best, Daan. ---------------------------------------------------------------------- wxHaskell is a portable GUI library for Haskell. The goal of the project is to provide an industrial strength portable GUI library, but without the burden of developing (and maintaining) one ourselves. wxHaskell is therefore build on top of wxWidgets -- a comprehensive C++ library that is portable across all major GUI platforms; including GTK, Windows, X11, and MacOS X. Furthermore, it is a mature library (in development since 1992) that supports a wide range of widgets with native look-and-feel, and it has a very active community (ranked among the top 25 most active projects on sourceforge). Since most of the interface is automatically generated from the wxEiffel binding, the current release of wxHaskell already supports about 75% of the wxWindows functionality -- about 2900 methods in 500 classes with 1400 constant definitions. wxHaskell has been build with GHC 6.x on Windows, MacOS X and Unix systems with GTK. A binary distribution is available for Windows, Linux (RPM) and MacOS X. And even if you don't intend to write GUI's yourself, it will be fun to check out the screenshots at <http://wxhaskell.sourceforge.net>. All the best, Daan Leijen.

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RTA'04: call for participation
by femke＠few.vu.nl 02 Apr '04

02 Apr '04

************************************* * * * RTA'04 CALL FOR PARTICIPATION * * * ************************************* The 15th International Conference on REWRITING TECHNIQUES AND APPLICATIONS http://www-i2.informatik.rwth-aachen.de/RTA04/ and the workshops * HOR 2nd int. workshop on higher-order rewriting * RULE 5th int. workshop on rule-based programming * WFLP 13th int. workshop on functional and (constraint) logic programming * WRS 4th int. workshop on reduction strategies in rewriting and programming * WST 7th int. workshop on termination * WG 1.6 IFIP working group 1.6 on term rewriting together form the Federated Conference on Rewriting, Deduction and Programming (RDP'04). RDP'04 takes place in Aachen, Germany, in the period May 31 - June 5, 2004. Registration for RTA and the workshops is now open ! The deadline for early registration is APRIL 30, 2004. Please see the webpage for further information. INVITED TALKS will be given at RTA'04 by: * Neil Jones (Copenhagen) * Aart Middeldorp (Innsbruck) * Robin Milner (Cambridge) For further questions please contact the conference chair: RTA'04 CONFERENCE CHAIR: Juergen Giesl RWTH Aachen giesl(a)informatik.rwth-aachen.de

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RE: [Haskell] Dynamically loading wxhaskell?
by Simon Marlow 01 Apr '04

01 Apr '04

> Has anyone succeeded in getting wxhaskell to work under ghci on Linux? > On my system, I get an error message > > Loading package unix ... ghc-6.2: can't load .so/.DLL for: dl > (libdl.so: cannot open shared object file: No such file or directory) > > This sounds like it has nothing to do with wxhaskell, but is a GHC > problem. Any pointers? Is libdl.so in the usual place? (/usr/lib on my system) Cheers, Simon

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DALT'04 : Deadline Extension
by DALT'04 01 Apr '04

01 Apr '04

------------------------------------------------------------- NEW DEADLINE: Online Paper Registration: April 6th Online Paper Submission: April 8th The Second International Workshop on Declarative Agent Languages and Technologies (DALT-2004) to be held at AAMAS 2004 with post-proceedings published by Springer <http://centria.di.fct.unl.pt/~jleite/dalt04/index.htm> -------------------------------------------------------------

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