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Re: infelicity in module imports
by Malcolm Wallace 04 Jul '01

04 Jul '01

| > Currently, you are permitted to write | > | > import A hiding (f) | > import B as A (f) | > | > and this means that everything exported from module A is visible, | > with the exception that function `f' is overridden by a different | > definition from module B. Here, a reference to `A.f' is resolved | > unambiguously to `B.f'. | | In my understanding of the report, this is not true. Quoting from section | 5.3 of the report | | "The hiding clause only applies to unqualified names. In the previous | example, the name M.C is brought into scope." | | Thus, in your example, the declaration import A hiding (f) will bring | A.f into scope and thus A.f is ambiguous! You are possibly correct, although both nhc98 and ghc actually resolve it in the manner I expected. However, if you are indeed correct, then we have an even stranger situation: import A (g) brings only A.g into scope, but import A hiding (f) brings both A.f and A.g into scope! So `hiding' is doing the opposite of hiding, and in fact _reveals_ names. Regards, Malcolm

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infelicity in module imports
by Malcolm Wallace 04 Jul '01

04 Jul '01

I was considering submitting this as a bug report in the Haskell'98 definition, but I don't know whether that is the appropriate designation or not. In any case, I think it is probably caused by a hang-over from a previous version of Haskell that never caught up with the newer features added in '98. The problem is the combination of qualified imports, explicit hiding, and renamed imports with overlapping. Currently, you are permitted to write import A hiding (f) import B as A (f) and this means that everything exported from module A is visible, with the exception that function `f' is overridden by a different definition from module B. Here, a reference to `A.f' is resolved unambiguously to `B.f'. However, should you wish to do the same trick with all names forced to be qualified, it is not legal. import qualified A hiding (f) import qualified B as A (f) Although this looks like a very similar case, the standard says that a `hiding' clause has no effect on a qualified import. Hence, even though the programmer has clearly tried to make it non-ambiguous, a reference to `A.f' cannot be resolved between `A.f' and `B.f', and such a program is rejected. I submit that the way `hiding' clauses are ignored is a vestige from the days when it was not possible to have overlapped module renamings. Now that overlapped renamings are possible, the `hiding' clauses should be permitted to take effect. Regards, Malcolm

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RE: infelicity in module imports
by Simon Marlow 04 Jul '01

04 Jul '01

Malcolm Wallace writes: > I submit that the way `hiding' clauses are ignored is a vestige from > the days when it was not possible to have overlapped module renamings. > Now that overlapped renamings are possible, the `hiding' clauses > should be permitted to take effect. I think you're right. It's inconsistent that you can specify which qualified identifiers are imported using 'import A ( foo, bar )' but not using the hiding form. The following two sentences could just be deleted from point 2, section 5.3: "The hiding clause only applies to unqualified names. In the previous example, the name M.C is brought into scope. A hiding clause has no effect in an import qualified declaration." Cheers, Simon

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Re: ghc 5 on mac os x
by Sebastien Carlier 03 Jul '01

03 Jul '01

> I was just wondering if you have tried to get the OS X > port of GHC 5 to work. I tried compiling this monster > with GHC 4.08.1, but could not get around what > appeared to be syntax errors showing up in the source. > > Have you made any progress? I have built a binary distribution which is just to be untared in /usr/local. I have been using it for a while and it seems to work fine. It is quite large (25Mb), is there a public ftp site where I could upload it ? I have a 5.00.2 being slowly compiled, it will probably be ready tomorrow. Sebastien

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30th SPRING SCHOOL THEORETICAL COMPUTER SCIENCE
by Ecole d'ete 2001 03 Jul '01

03 Jul '01

======================================================================= 30th SPRING SCHOOL THEORETICAL COMPUTER SCIENCE 24 - 29 March, 2002 in AGAY (VAR, FRANCE) PRELIMINARY ANNOUNCEMENT [Apologies for multiple copies] ======================================================================= This spring school aims at bringing together students and researchers eager to learn about the fundamental questions which language designers and implementors are facing those days, and on the most up-to-date tools that theoreticians have developed or are in the process of developing (such as games and ludics, or realisability for classical logic and set theory). Denotational semantics was born some thirty years ago from the encounter of computer scientists who aimed at implementation independent definitions of programming constructs on one hand, and logicians who provided mathematical tools to this aim (domain theory) on the other hand. Algebraic tools such as initial algebra semantics were also instrumental to the birth of this subject. Thirty years later, the subject has enriched considerably, both in tools (including connections with proof theory and category theory) and in coverage and applications (functional programming, state, control, objects, parallelism, mobility,...). Concepts and constructs that have arisen in the design of programming languages have found counterparts in logic, logical systems have found their way to applications in the form of proof assistants, etc... The rapid development of new programming paradigms, in which distributed computation takes a more and more important part, infers a strong demand on theory, more than ever. With the rise of quite specialized subcommunities (like type theory, linear logic, pi-calculus, functional programming, etc...), it is important to keep an eye on more comprehensive training events, that can address the interrelations between research areas in rapid growth, and between theory-oriented research work and more goal-oriented one, with the prospect of solving problems or of improving our understanding in one domain using tools of another domain. The diversity of the proposed lectures, combined with their conceptual overall unity (as witnessed by the very limited number of core formal systems: lambda-calculus, linear logic, pi-calculus) addresses this issue. ======================================================================= LECTURES ======================================================================= Denotational semantics and games semantics (5 hours) : Thomas Ehrhard , Guy McCusker Ludics (4 hours) : Pierre-Louis Curien, Jean-Yves Girard Realisability (4 hours) : Vincent Danos, Jean-Louis Krivine Continuations (4 hours) : Olivier Danvy Compilation, objects, modules (4 hours) : Xavier Leroy Mobility (5 hours) : Luca Cardelli, Cedric Fournet Security (5 hours) : Martin Abadi, Francois Pottier ======================================================================= CONTACT & FURTHER INFORMATION ======================================================================= http://www.pps.jussieu.fr/~ecole/ email: ecole(a)pps.jussieu.fr Equipe Preuves Programmes et Systèmes Université Denis Diderot Case 7014 2 Place Jussieu 75251 PARIS Cedex 05 FRANCE

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CFP: PEPM'02
by Peter Thiemann 02 Jul '01

02 Jul '01

FIRST CALL FOR PAPERS 2002 ACM SIGPLAN Workshop on Partial Evaluation and Semantics-Based Program Manipulation (PEPM'02) Portland, Oregon, USA, January 14-15, 2002 (preceding POPL'02) http://www.informatik.uni-freiburg.de/~thiemann/pepm02 Submission deadline: 8 October, 2001 The PEPM'02 workshop will bring together researchers working in the areas of semantics-based program manipulation, partial evaluation, and program generation. The workshop focuses on techniques, supporting theory, and applications of the analysis and manipulation of programs. Technical topics include, but are not limited to: * Program manipulation techniques: transformation, specialization, normalization, reflection, rewriting, run-time code generation, multi-level programming. * Program analysis techniques: abstract interpretation, static analysis, binding-time analysis, attribute grammars, constraints. * Related issues in language design and models of computation: imperative, functional, logical, object-oriented, parallel, distributed, mobile, secure, domain-specific. * Programs as data objects: staging, meta-programming, incremental computation, mobility, tools and techniques, prototyping and debugging. * Applications: systems programming, scientific computing, algorithmics, graphics, security checking, simulation, compiler generation, compiler optimization, decompilation. * Assessment: applicability of program manipulation techniques to particular architectures and language paradigms, scalability, benchmarking, portability. Original results that bear on these and related topics are solicited. Papers investigating novel uses and applications of program manipulation in the broadest sense are especially encouraged. Authors concerned about the appropriateness of a topic are welcome to consult with the program chair prior to submission. SUBMISSION INFORMATION Papers should be submitted electronically via the workshop's Web page. Exceptionally, submissions may be emailed to the program chair: <URL:mailto:thiemann@uni-freiburg.de>. Acceptable formats are PostScript or PDF, viewable by gv. Submissions should not exceed 5000 words, excluding bibliography and figures. Excessively long submissions may be rejected outright. Submitted papers will be judged on the basis of significance, relevance, correctness, originality, and clarity. They should include a clear identification of what has been accomplished and why it is significant. They must describe work that has not previously been published in a major forum. Authors must indicate if a closely related paper is also being considered for another conference or journal. Proceedings will be published with ACM Press. A special issue of the journal "Higher-Order and Symbolic Computation" <URL:http://www.wkap.nl/journals/lasc> is planned afterwards. PROGRAM COMMITTEE Maria Alpuente (U. Politécnica de Valencia, Spain) Evelyn Duesterwald (Hewlett-Packard Labs, USA) Robert Glück (DIKU, Denmark and Waseda University, Japan) Michael Hanus (Christian-Albrecht-University of Kiel, Germany) Zhenjiang Hu (University of Tokyo, Japan) John Hughes (Chalmers Technical University, Sweden) Mark Jones (OGI, USA) Siau-Cheng Khoo (NUS, Singapore) Jakob Rehof (Microsoft Research, USA) João Saraiva (University of Minho, Portugal) Ulrik Schultz (University of Aarhus, Denmark) Peter Thiemann (University of Freiburg, Germany, chair) David Walker (CMU, USA)

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WFLP 2001 - Call for Participation
by Frank Steiner 02 Jul '01

02 Jul '01

************************** * Call for Participation * ************************** WFLP 2001 International Workshop on Functional and (Constraint) Logic Programming http://www.informatik.uni-kiel.de/~wflp2001 comprising the 10th International Workshop on Functional and Logic Programming and 16th Workshop on Logic Programming Kiel, Germany September 13-15, 2001 Early Registration and Hotel Reservation Deadline: July 15, 2001 ====================================================================== GENERAL WFLP 2001 is the combination of two workshops of a successful series of annual workshops on declarative programming. The international workshops on functional and logic programming aimed at bringing together researchers interested in functional programming, logic programming, as well as their integration. Previous workshops have been held in Benicassim (Spain), Grenoble (France), Bad Honnef (Germany). The workshops on (constraint) logic programming are the annual meeting of the Society of Logic Programming (GLP e.V.) and bring together researchers interested in logic programming, constraint programming, and related areas like databases and artificial intelligence. Previous workshops have been held in Germany, Austria and Switzerland. In this year both workshops will be jointly organized in order to promote the cross-fertilizing exchange of ideas and experiences among researches and students from the different communities interested in the foundations, applications, and combinations of high-level, declarative programming languages and related areas. ---------------------------------------------------------------------- REGISTRATION Information concerning registration and accommodation can be found at the workshop web page at http://www.informatik.uni-kiel.de/~wflp2001 Note that the EARLY REGISTRATION AND HOTEL ACCOMMODATION DEADLINE is July 15th, 2001. ---------------------------------------------------------------------- TECHNICAL PROGRAM The technical program includes: INVITED TALKS by Peter Van Roy (Catholic University of Louvain) Thomas Arts (Ericsson) ACCEPTED PAPERS: Slim Abdennadher, Ekkerhard Krämer, Matthias Saft, Matthias Schmauss: JACK: A Java Constraint Kit M. Alpuente, F. Correa, M. Falaschi: A Debugging Scheme for Functional Logic Programs Sandra Alves, Mário Florido : Type Inference using Constraint Handling Rules Sergio Antoy, Michael Hanus, Bart Massey, Frank Steiner: An Implementation of Narrowing Strategies Sergio Antoy, Pascual Julian Iranzo, Bart Massey: Improving the Efficiency of Non-Deterministic Computations Jeremie Blanc and Rachid Echahed: Adding Time to Functional Logic Programs Rafel Caballero, Mario Rodriguez-Artalejo: A Declarative Debugger of Wrong Answers for Lazy Functional Logic Programs Rachid Echahed, Wendelin Serwe: Integrating Action Definitions into Concurrent Declarative Programming Rachid Echahed, Wendelin Serwe: A Component-Based Approach to Concurrent Declarative Programming Lucilia Figueiredo, Carlos Camarão: Principal Typing And Mutual Recursion Erik Johansson, Konstantinos Sagonas: Linear Scan Register Allocation in the HiPE Compiler Frank Huch: Model Checking Erlang Programs - Abstracting the Context-Free Structure J. E. Labra Gayo, M. C. Luengo Díez, A. Cernuda del Río: Specification of Logic Programming Languages from Reusable Semantic Building Blocks Salvador Lucas: Context-Sensitive Rewriting, Lazy Rewriting, and On-Demand Rewriting Hiroshi Mabuchi, Kiyoshi Akama, Hidekatsu Koike: Emergent Computation for Semantic Interpretation by Rule-Based Equivalent Transformation Hiroshi Mabuchi, Kiyoshi Akama, Hidekatsu Koike: Synthesis of Conversion Rules by Expanding Logic Programs Chieko Nakabasami: Inducing differences among Documents using Aleph with Construction of Background Knowledge Miguel Palomino Tarjuelo: Comparing Meseguer's Rewriting Logic with the Logic CRWL Bernard Pope, Lee Naish: Specialisation of Higher-Order Functions for Debugging André Rauber Du Bois, Jorge Luis Victória Barbosa, Cláudio Fernando Resin Geyer: Adding Functional Programming into the Holo Language Georg Ringwelski: An Asynchronous Execution Model for Constraint Processing in Object-Oriented Software Shinya Sato, Toru Sugimoto, Shinichi Yamada: An implementation model of the typed lambda-calculus based on Linear Chemical Abstract Machine Sibylle Schwarz: Stable Generated Models of Generalized Constraint Logic Programs Dietmar Seipel, Ulrich Geske: Solving Cardinality Constraints in (Constraint) Logic Programming Manfred Widera: A Sketch of Complete Type Inference for Functional Programming SYSTEM DEMONSTRATIONS: Rudolf Berghammer: KIEL - A Computer System for Visualizing the Execution of Functional Programs Alfred Fent, Burkhard Freitag: ULTRAflow - A Lightweight Workflow Management System Michael Hanus, Johannes Koj: CIDER: An Integrated Devlopment Environment for Curry ---------------------------------------------------------------------- CONTACT WFLP 2001 Prof. Michael Hanus Institut fuer Informatik und Praktische Mathematik Christian-Albrechts-Universitaet Kiel Olshausenstr. 40 D-24098 Kiel, Germany Phone: ++49-(0)431-880-7271 or -7270 (Secr.) Fax : ++49-(0)431-880-7613 Email: wflp2001(a)informatik.uni-kiel.de ---------------------------------------------------------------------- PROGRAM COMMITTEE Slim Abdennadher (LMU Muenchen) Maria Alpuente (UP Valencia) Sergio Antoy (Portland State University) Christoph Beierle (FernUniv. Hagen) Alexander Bockmayr (Univ. Henri Poincare, Nancy) Harold Boley (DFKI Kaiserslautern) François Bry (LMU Muenchen) Juergen Dix (Univ. Manchester) Rachid Echahed (IMAG, Grenoble) Uwe Egly (TU Wien) Moreno Falaschi (Univ. Udine) Burkhard Freitag (Univ. Passau) Thom Fruehwirth (LMU Muenchen) Norbert E. Fuchs (Univ. Zuerich) Ulrich Geske (GMD-FIRST Berlin) Michael Hanus (CAU Kiel) Herbert Kuchen (Univ. Muenster) Juan Jose Moreno Navarro (UP Madrid) Mario Rodriguez-Artalejo (UC Madrid) Dietmar Seipel (Univ. Wuerzburg) ----------------------------------------------------------------------

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CALL FOR PARTICIPATION: European Summer School in Logic, Language and Information (ESSLLI'01), August 13-24, 2001 (Helsinki, Finland)
by Ahti Pietarinen 01 Jul '01

01 Jul '01

CALL FOR PARTICIPATION **Registration possible until the start of the event** 13th European Summer School in Logic, Language and Information ESSLLI 2001 University of Helsinki FINLAND August 13-24, 2001 http://www.helsinki.fi/esslli GENERAL INFORMATION The 13th European Summer School in Logic, Language and Information (ESSLLI'01) takes place at the University of Helsinki, Helsinki, Finland, during two weeks in August, from August 13 until 24. The ESSLLI Summer Schools are organised under the auspices of FoLLI (http://www.folli.uva.nl) the European Association for Logic, Language and Information. The main focus of the Summer School is the interface between linguistics, logic and computation. Foundational, introductory and advanced courses, workshops and special events cover a wide variety of topics within six areas of interest: * Logic * Language * Computation * Logic and Language * Logic and Computation * Language and Computation The number of courses offered is over 50. Previous summer schools have been highly successful, attracting around 500 students from Europe and elsewhere. The school has developed into an important meeting place and forum for discussion for students, researchers and IT professionals interested in the interdisciplinary study of Logic, Language and Information. In addition to courses, workshops and evening lectures, there will be a Student Session and a social program. COURSE PROGRAM The full scientific program can be found at our home page http://www.helsinki.fi/esslli/ Evening Lectures are given by * Edward L. Keenan "Spinoza Lecture" (UCLA) * Yannis Moschovakis "Vienna Circle Lecture" (UCLA) * Keith Devlin (Saint Mary's College, California) * Jaakko Hintikka (Boston & Helsinki) * Bonnie Webber (Edinburgh) "Twenty Years of Finite-State Methods", special event organised by Lauri Karttunen, Kimmo Koskenniemi and Gertjan van Noord. WORKSHOPS Logic: "Logic and Games" (Gabriel Sandu and Marc Pauly) http://www.cwi.nl/~pauly/GameLogic/esslli-workshop.html Language: "Information Structure, Discourse Structure and Discourse Semantics" (Ivana Kruijff-Korbayová and Mark Steedman) http://www.coli.uni-sb.de/~korbay/esslli01-wsh/index.html Computation: "Automata and Finite Model Theory" (Lauri Hella, Juhani Karhumäki and Kerkko Luosto) http://www.helsinki.fi/esslli/workshops/AFMT.html Language and Logic: "Choice Functions and Natural Language Semantics" (Klaus von Heusinger, Ruth Kempson and Wilfried Meyer-Viol) http://www.ling.uni-konstanz.de/pages/home/heusinger/konf-proj/ESSLLI/ Logic and Computation: "Coordination and Action" (Peter Kühnlein, Alison Newlands and Hannes Rieser) http://www.lili.uni-bielefeld.de/~pkuehnle/HELSINKI/ Language and Computation: "Semantic Knowledge Acquisition and Categorisation" (Alessandro Lenci, Simonetta Montemagni and Vito Pirrelli) http://www.ilc.pi.cnr.it/~esslli/ "Finite-State Methods in Natural Language Processing" (Lauri Karttunen, Kimmo Koskenniemi and Gertjan van Noord) http://www.let.rug.nl/~vannoord/alp/esslli_fsmnlp/ "Mathematics of Language" (Larry Moss and Dick Oehrle) http://www.helsinki.fi/esslli/workshops/MoL.html TRAVEL AND LOCAL INFORMATION By plane to Helsinki airport and then a 35-minute nonstop coach or taxi service to the main railway station. From the railway station 5-minute walk to the university. A gateway between East and West, the city of Helsinki (population 1M) is the capital of Finland and one of the nine European Cities of Culture for the millennium. It is located at the south coast of Finland, within an easy reach from the main airports worldwide, or inside Europe by car or regular train services, or using the ferry services operating within the Baltic region. The scientific program of ESSLLI'01 will be held in the University Main Building, located on the University city campus at the centre of Helsinki. ACCOMMODATION The accommodation organised by ESSLLI is fully booked now. Please go to http://www.helsinki.fi/esslli to try alternative options. REGISTRATION Please go to http://www.helsinki.fi/esslli and complete the on-line registration form. GRANTS The ESSLLI'01 grant scheme is closed now. SPEACIAL EVENTS In the weekend preceding ESSLLI, a "Finnish for Foreigners" language course is organised. During ESSLLI, there will be excursions and other social events. Helsinki Summer School (http://summerschool.helsinki.fi) offers special deals for ESSLLI participants who want to choose some of their courses and earn credits. SATELLITE EVENTS The Association for the Mathematics of Language will stage its annual meeting (MoL7) in conjunction with ESSLLI, in the weekend preceding ESSLLI (August 10-12). The Formal Grammar Conference will be held in conjunction with the Mathematics of Language Conference. The registration fee is 50 euros. Conference Description and Program: http://sfinx.let.uu.nl/users/fgmol01prog.pdf PROGRAM COMMITTEE Marcus Kracht (Chair) <kracht(a)math.fu-berlin.de> Jouko Väänänen (Logic) Bonnie Webber (Language) Claude Kirchner (Computation) Michael Moortgat (Logic and Language) Steffen Hölldobler (Computation and Logic) Claire Gardent (Language and Computation) CONTACT ADDRESS Please visit ESSLLI'01 Home Page http://www.helsinki.fi/esslli for updated information concerning the scientific program, registration fees and procedures, grants, accommodation, satellite events, and other practical information. For further enquiries concerning ESSLLI'01, please contact the Organising Committee at <esslli(a)helsinki.fi>, or write to ESSLLI 2001 Secretariat c/o Department of Philosophy P.O. Box 9 FIN-00014 University of Helsinki Finland ESSLLI'01 is organised by the Department of Philosophy (coordinator), the Department of Mathematics, the Department of General Linguistics, and the Department of Computer Science at the University of Helsinki. ORGANISING COMMITTEE Gabriel Sandu (Chair, Philosophy) Jouko Väänänen (Mathematics) Fred Karlsson (General Linguistics) Ilkka Niiniluoto (Philosophy) Martti Tienari (Computer Science) Ahti Pietarinen (Philosophy, secretariat) <esslli(a)helsinki.fi> =========================================================================

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Re: library Directory.hs
by Sigbjorn Finne 27 Jun '01

27 Jun '01

Nicole Gabler Nicole.Gabler(a)web.de writes: > > thank you for all your answers. I solved the problem without > using Directory.hs, but now I have a new problem and now > I need Directory.hs. I only have the name of a directory and I > have to search for any files in this directory! Unfortunately, the > business concern, where I'm doing an industrial practical, don't > use Unix but Windows NT. So, what can I do?? Hi, I'd suggest either waiting for the next release of Hugs98, or grab a copy of the Hugs98 sources from the CVS repository (http://cvs.haskell.org/ & compile it up. It has a complete set of Haskell98 modules, including Directory. If neither of these options are practical, let me know & I'll send you a copy of the files you need. hth --sigbjorn

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Re: hbc
by Stephen Bailey 27 Jun '01

27 Jun '01

> Why hbc did not succeeded? I heard rumors that the author went off to some cushy industrial job, or is spending all his time writing NetBSD drivers, or something like that :^) Steph

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