February 2002 - Haskell

foralls in class assertions
by Ashley Yakeley 16 Feb '02

16 Feb '02

It would be nice to be able to put foralls in class assertions. For instance: class HasIdentity a where { identity :: a; }; class Composable a b ab | a b -> ab where { compose :: a -> b -> ab; }; class ( forall a. HasIdentity (m a a), forall a b c. Composable (m b c) (m a b) (m a c) ) => Category m; instance ( forall a. HasIdentity (m a a), forall a b c. Composable (m b c) (m a b) (m a c) ) => Category m; Or even allow the foralls their own context: foo :: (forall a. (C a b) => D a c) => T b c; Does this make sense? Would it have unpleasant consequences? -- Ashley Yakeley, Seattle WA

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Stuck between Prolog and Smalltalk
by Justin Walsh 16 Feb '02

16 Feb '02

Hi, This is my first email to Haskell.org, and am very much a Haskell newbie. I have been fighting with Prolog and Smalltalk devotees for so many years: each one seeming to treat the other as the "arch" enemy. Perhaps I can get better response from the Haskell community. I have been, for the last ten years, acting upperCase(philosophical) and lowerCase (technical) researcher/consultant to Heyile Pty Ltd. in Sydney Australia. The purpose of the Ripose Technology is to provide the Conceptual missing link that has, for years evaded Smalltalk and Prolog application designers ie provision of Industriel strength, Enterprise Wide Definition and Business Wide (software) Definitions. The EWD seemed always to be a consensus, an agreement to fail. Every application had to be carefully hand crafted by a language programmer, acting for the business in accordance with what the programmer thought the entepreneur needed. Where is the industrial strength? Metaphysics seemed all they have to fall back on. When I met this guy, Richter, in 1992 I saw something mind bogglingly different in the way he designed business application: in hours rather than years and accurate. I agreed to use him and his technique to design for himself, free of charge, his own Business (Ripose Pty Ltd) and Enterprise (Ripose.Foundation) as proof of the Ripose concept, in return for the important front end: the Conceptual Pre-processor. This effectivily becomes free of charge to the design community. The Ripose Foundation (still only and idea) needs good disciplined competent programmers who do not feel insulted if they are required to program to strict definition. In short no hackers. The toolset is currently limited by the tools he was compelled to use for the last ten years: Omnis. I believe that the free bit could be redone in Haskell. The rewards are limited only by the imagination. Am I barking up the wrong tree? http://www.ripose.com/Mydream/ Please proceed to the price list to see the free bits. In my opinion the most important attributes. Justin Walsh ===Last conversation between Richter and a Foundation member========= Gerhard Thanks for your response. Omnis Studio is only my suggestion because I know the product fairly well and the Caspar (computer assisted strategic planning and reasoning) engine is the robust client server version currently running very well at the moment. The data base design behind Caspar is probably even more important than the code itself. Hence it does not matter to me whether the final eCaspar is written in Omnis Studio or anything else. If the response times of eCaspar are better than or even comparable to Caspar, I would have no hesitation to have Caspar replaced by eCaspar. This would then obviate the need to maintain two sets of code. The reason behind this statement is that I have still not successfully found a way to do a simple <a href> in the Omnis Studio Web based product. If this is not achieved then my whole strategy of delivering eCaspar in Omnis Studio, is in jeopardy. Quite frankly I do not really see the need to web enable Caspar as Caspar is probably more efficient and effective in its client server form than it will be if it was web enabled. Just to satisfy a few people who like the look and feel of a program running in a web browser does not appear to be a very sound strategy. They will still have to learn how to use the product and then decide to use our services! The main benefit of using Ripose and Caspar is to assist an entrepreneur rapidly design their ideal world and then test whether or not the idea will 'fly'. This must be done before investing any more of their or someone else's (business person's) hard earned money. Anyone interested in 'opportunism' will shy away from using Ripose and hence Caspar. Ripose achieves this benefit by providing the steps a Ripose architect has to take in order to clarify the idea/dream/thinking of the initiator/entrepreneur and thus produce/develop the ideal world and then test the idea. It does this by creating a hierarchy of objects and getting the entrepreneur, business person, technical person and process worker to clarify the following: a.. Concept behind the entrepreneur/business/person's existence by delivering the idea via two deliverables - objectives and a proof of concept. These two documents describes the: a.. Objects of the imagination - ie the objectives a.. Goals (1 Purpose, 4 missions/benefits and critical success factors (CSF) b.. The measures supporting each CSF, namely a.. Key performance indicators (KPI) b.. Service level agreements (SLA) b.. Objects behind the understanding of the objectives, namely the: a.. Knowledge base required to support the KPIs b.. Prioritized core and ancillary strategies/business functions and tactics/systems which will be needed to implement the knowledge base b.. Objects of reasoning - ie the logic required to test the understanding, by delivering the proof of logic containing the: a.. Data architecture - containing the following objects a.. The facts/data/attributes supporting each object/entity in the knowledge base b.. The data bases containing the 'normalized' or 'de-normalized' facts b.. Process architecture - containing the following objects a.. The high level processes - eg 'read a file', 'open a window' b.. The structured pseudo code, utilizing the processes to act on the data base - sequence, selection and iteration Finally we are now in a position for SQL and the languages to begin to 'strut their stuff' The Ripose technique and Caspar almost guarantee that the three deliverables will be delivered in less than 3 months. The time frame depends on the number of people in the enterprise a.. Objectives - about 10 days maximum - see http://www.ripose.com/Objectives.html for the savings associated with delivering the objectives b.. Strategies - about 20 days maximum - see http://www.ripose.com/Strategies.html for the savings associated with delivering the knowledge base and strategies c.. Logic - this depends on the number of tactics/systems chosen together with the number of tables in the associated data bases. The rule of thumb is not more than 10 working days for a data base containing 20 tables I do not see how any other product on the market delivers the same benefit as Ripose and Caspar! To build the Ripose enterprise (both the dot com and dot org sides) is no longer solely my responsibility. We need adult human beings to assist us. Hope this helps clear more of the mist. Regards ____________________________________ Charles Richter Ripose Pty Limited PO Box 244 Paddington NSW 2021 Australia Voice (02) 8900 3234 Mobile (04) 2520 3234 Facsimile (02) 9437 9237 Web site http://www.ripose.com Newsletter November 2001 http://www.ripose.com/NewsLetters/Issue03/Page1.html ================================================================ Gerhard wrote: I agree with you that you should stick to omnis studio after so amny years of experience with it, I did not know that detail.(I look now at Omnis studio: I see that it is possible to connect to Apache , which can connect to mySQL...)

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Final CFP: Special Journal Issue on Proof-Carrying Code
by Amy Felty 15 Feb '02

15 Feb '02

Final Call for Papers JOURNAL OF AUTOMATED REASONING Special issue on PROOF-CARRYING CODE Proof-carrying code is a technology that allows a host, or code consumer, to safely run code delivered by an untrusted code producer. The code producer delivers both a program and a formal proof that verifies that the code meets the desired safety policies. Safety policies generally express properties that prohibit the code from harmful behavior such as accessing private data, overwriting important data, accessing unauthorized resources, or consuming too many resources. Ideally, a proof is constructed automatically, and proof search may be directed using information that is passed on from the code producer's compiler. Proofs provided semi-automatically or interactively using a proof assistant are possible as well. Upon receiving the code and proof, the code consumer uses a mechanical proof checker to check the proof before executing the code. This special issue will be devoted to the topic of proof-carrying code and related approaches which use formal reasoning to enhance safety and reliability of software. Manuscripts emphasizing original results and study of tools and methods for proof generation, proof checking, and their integration with code generation/compilation are of particular interest. Manuscripts should be unpublished works and not submitted elsewhere. Revised and enhanced versions of papers published in conference proceedings that have not appeared in archival journals are eligible for submission. All submissions will be reviewed according to the usual standards of scholarship and originality. Information on JAR submissions can be found at URL http://www-unix.mcs.anl.gov/JAR/. Please format your submissions using JAR macros (available at http://www.wkap.nl/kaphtml.htm/STYLEFILES) Submissions should be sent to the guest editor in postscript format, preferably gzipped and uuencoded. In addition, please send as plain text, the title, authors, abstract, and contact information for the paper. The submission deadline is February 22, 2002. Guest Editor: Amy Felty, University of Ottawa, afelty(a)site.uottawa.ca This information is available on the web at: http://www.site.uottawa.ca/~afelty/jar-pcc/

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ESSLLI 2002 Student Session
by Malvina Nissim 15 Feb '02

15 Feb '02

!!! Concerns all students in Logic, Linguistics and Computer Science !!! !!! Please circulate and post among students !!! We apologise if you receive this message more than once. ESSLLI-2002 STUDENT SESSION ** LAST CALL FOR PAPERS ** August 5-16 2002, Trento, Italy Deadline: February 25th, 2002 www.iccs.informatics.ed.ac.uk/~malvi/esslli02 We are pleased to announce the Student Session of the 14th European Summer School in Logic, Language and Information (ESSLLI-2002) organised by the Centre for scientific and technological research (ITC-irst) in Trento and by the University of Trento, under the auspices of the European Association for Logic, Language and Information (FoLLI). ESSLLI-2002 will be held in Trento from August 5-16 2002. We invite submission of papers for presentation at the ESSLLI-2002 Student Session and for appearance in the proceedings. PURPOSE: This seventh ESSLLI Student Session will provide, like the other editions, an opportunity for ESSLLI participants who are students to present their own work in progress and get feedback from senior researchers and fellow-students. The ESSLLI Student Session encourages submissions from students at any level, from undergraduates (before completion of the Master Thesis) as well as postgraduates (before completion of the PhD degree). Papers co-authored by non-students will not be accepted. Papers may be accepted for full presentation (30 minutes including 10 minutes of discussion) or for a poster presentation. All the accepted papers will be published in the ESSLLI-2002 Student Session proceedings, which will be made available during the summer school. KLUWER BEST PAPER AWARD: As in previous years, the best paper will be selected by the programme committee and will be offered a prize of 600 euros by Kluwer Academic Publishers to be spent on books. REQUIREMENTS: The Student Session papers should describe original, unpublished work, completed or in progress that demonstrates insight, creativity, and promise. No previously published papers should be submitted. Note that the ESSLLI02 school will be focused on the three main interdisciplinary areas (Logic & Language, Logic & Computation, and Language & Computation), while the single areas have been dropped. Given the high interest shown over the years, the Student Session will keep two of the single areas, namely Logic and Language, welcoming thus submissions within the following topics: Logic, Language, Logic & Language, Logic & Computation, Language & Computation. FORMAT OF SUBMISSION: Student authors should submit an anonymous full paper headed by the paper title, not to exceed 7 pages of length exclusive of references and send a separate identification page (see below). Note that the length of the final version of the accepted papers will not be allowed to exceed 10 pages. Since reviewing will be blind, the body of the paper should omit author names and addresses. Furthermore, self-references that reveal the author's identity (e.g., "We previously showed (Smith, 1991)... ") should be avoided. It is possible to use instead references like "Smith (1991) previously showed...". For any submission, a plain ASCII text version of the identification page should be sent separately, using the following format: Title: title of the submission First author: firstname lastname Address: address of the first author ...... Last author: firstname lastname Address: address of the last author Short summary: abstract (5 lines) Subject area (one of): Logic | Language | Logic and Language | Logic and Computation | Language and Computation If necessary, the programme committee may reassign papers to a more appropriate subject area. The submission of the paper should be in one of the following formats: PostScript, PDF, RTF, or plain text. But note that, in case of acceptance, the final version of the paper has to be submitted in LaTeX format. Please, use A4 size pages, 11pt or 12pt fonts, and standard margins. Submissions outside the specified length and formatting requirements may be subject to rejection without review. The paper and separate identification page must be sent by e-mail to: malvi(a)cogsci.ed.ac.uk by FEBRUARY 25th 2002 ESSLLI-2002 INFORMATION: In order to present a paper at ESSLLI-2002 Student Session, at least one student author of each accepted paper has to register as a participant at ESSLLI-2002. The authors of accepted papers will be eligible for reduced registration fees. For all information concerning ESSLLI-2002, please consult the ESSLLI-2002 web site at www.esslli2002.it IMPORTANT DATES: Deadline for submission of papers: February 25, 2002. Authors notifications: April 22, 2002. Final version due: May 20, 2002. ESSLLI-2002 Student Session: August 5-16, 2002. PROGRAMME COMMITTEE: David Ahn, University of Rochester (Language and Computation) Carlos Areces, University of Amsterdam (Logic) Reinhard Blutner, University of Berlin (Language) Kees van Deemter, University of Brighton (Language and Computation) Paul Dekker, University of Amsterdam (Logic and Language) Juergen Dix, University of Manchester (Logic and Computation) Marta Garcia-Matos, University of Helsinki (Logic) Juan Heguiabehere, University of Amsterdam (Logic and Computation) Elsi Kaiser, University of Pennsylvania (Language) Malvina Nissim, University of Edinburgh (Chair) Rick Nouwen, University of Utrecht (Logic and Language) For any specific questions concerning ESSLLI-2002 Student Session, please, do not hesitate to contact me: Malvina Nissim ICCS, University of Edinburgh 2 Buccleuch Place, Edinburgh EH8 9LW, UK phone: +44 +(0)131 +650 4630 fax: +44 +(0)131 +650 6626 e-mail: malvi(a)cogsci.ed.ac.uk

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Working Conf on Generic Programming: deadline extension
by Jeremy Gibbons 15 Feb '02

15 Feb '02

The submission deadline for the IFIP TC2/WG2.1 Working Conference on Generic Programming has been extended until 2nd March 2002. For further details of the conference, please see the web site at http://www.cs.uu.nl/~johanj/wcgp/. A revised call for papers is attached. Jeremy Gibbons and Johan Jeuring (conference chairs) * * * WCGP '02 IFIP WG2.1 Working Conference on GENERIC PROGRAMMING http://www.generic-programming.nl/wcgp/cfp.html Organised in conjunction with MPC'02 July 8 - July 13, 2002 Dagstuhl, Germany CALL FOR PAPERS Generic programming is about making programs more adaptable by making them more general. Generic programs often embody non-traditional kinds of polymorphism; ordinary programs are obtained from them by suitably instantiating their parameters. In contrast with normal programs, the parameters of a generic programs are often quite rich in structure. For example they may be other programs, types or type constructors, class hierarchies, or even programming paradigms. Generic programming techniques have always been of interest, both to practitioners and to theoreticians, but only recently have generic programming techniques become a specific focus of research in the functional and object-oriented programming language communities. This working conference will bring together leading researchers in generic programming from around the world, and feature papers capturing the state of the art in this important emerging area. We welcome contributions on all aspects, theoretical as well as practical, of generic programming, aspect-oriented programming, polytypic programming, adaptive object-oriented programming, generic components, and so on. SUBMISSION Full papers should be submitted in Postscript or pdf format by e-mail to reach Jeremy.Gibbons(a)comlab.ox.ac.uk by March 2, 2002. The details of the submission procedure can be found at http://www.cs.uu.nl/~johanj/wcgp/submit.html Although there is no page limit, submissions should strive for brevity and clarity. IMPORTANT DATES Submission March 2, 2002 Notification April 12, 2002 Final version due May 24, 2002 PROGRAMME COMMITTEE Matt Austern Eerke Boiten Ulrich Eisenecker Jeremy Gibbons (co-chair) Ralf Hinze Johan Jeuring (co-chair) Gary Leavens Karl Lieberherr Lambert Meertens Eugenio Moggi Bernhard Moeller Oege de Moor David Musser Martin Odersky Ross Paterson Simon Peyton Jones Colin Runciman Doaitse Swierstra Stephanie Weirich LOCAL ORGANISATION Jeremy Gibbons Johan Jeuring Bernhard Moeller CORRESPONDENCE Jeremy Gibbons (Jeremy.Gibbons(a)comlab.ox.ac.uk) Johan Jeuring (johan(a)jeuring.net) -- Jeremy.Gibbons(a)comlab.ox.ac.uk Oxford University Computing Laboratory, TEL: +44 1865 283508 Wolfson Building, Parks Road, FAX: +44 1865 273839 Oxford OX1 3QD, UK. URL: http://www.comlab.ox.ac.uk/oucl/people/jeremy.gibbons.html

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Call for papers: TIP'02
by tip02＠informatik.uni-freiburg.de 14 Feb '02

14 Feb '02

Call for Papers Workshop on Types in Programming (TIP'02) Dagstuhl, Germany, July 9, 2002 Colocated with MPC'02 http://www.informatik.uni-freiburg.de/~thiemann/tip02/ Modern programming languages rely on type systems with static type checking to detect common errors at compile time. While the benefits of statically checked type systems have long been recognized, there are some areas where the type systems of modern programming languages are not expressive enough. Some interesting programs will always be rejected, despite their semantical soundness. There are several remedies to this situation, ranging from dependent types (where types may contain values) through intersection types to types with modalities. These systems are well-investigated from a theoretical point of view by logicians and type theorists. However, the impact of these developments on practical programming has been small, partly because they are trading simplicity against expressivity. The objective of the workshop is to make researchers in programming languages aware of new developments and research directions on the theory side while at the same time pointing out problems arising in practical uses to theorists. Technical topics include, but are not limited to: * Type systems in all variants: polymorphic, dependent, intersection, modal, linear. * Annotated type systems. * Low-level type systems. * Advanced uses and applications. Original results that bear on these and related topics are solicited. Papers investigating novel uses, applications, and shortcomings of type systems in the broadest sense are especially encouraged. Authors concerned about the appropriateness of a topic are welcome to consult with the program chairs at <URL:mailto:tip02@informatik.uni-freiburg.de> prior to submission. An extended abstract should be submitted electronically to <URL:mailto:tip02@informatik.uni-freiburg.de>. Acceptable formats are PostScript or PDF, viewable by gv. Submissions should not exceed 5000 words, excluding bibliography and figures. Submitted papers will be judged on significance, relevance, correctness, originality, and clarity. They should include a clear identification of what has been accomplished and why it is significant. Proceedings will appear as a technical report at INRIA. Deadline for submission: 27 April 2002 Notification: 1 June 2002 Final papers due: 29 June 2002 Program Committee: Gilles Barthe, INRIA Sophia-Antipolis, France [co-chair] Jacques Garrigue, Kyoto University, Japan Eugenio Moggi, University of Genova, Italy Zhong Shao, Yale University, USA Peter Thiemann, Universität Freiburg, Germany [co-chair] Joe Wells, Heriot-Watt University, Edinburgh, Scotland

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ANNOUNCE: Haskell support for JCreator update
by unknown＠example.com 13 Feb '02

13 Feb '02

Dear reader, I'm pleased to announce the availability of a release of the Haskell module for JCreator. You can get it, as usual, at http://www.students.cs.uu.nl/people/rjchaaft/JCreator The previous update lacks the documentation tool, and is quite restrictive concerning the location of Hugs, the Haskell Graphics Library and JCreator. This update reintroduces the documentation tool. The problems that were reported about the tool (incompatibilities between windows versions) are fixed (hopefully). The html version of Bernie Pope's Tour of the Haskell Prelude, made by Arjan van IJzendoorn is included as well (under the same documentation tool). The requirement that Hugs, the GraphicsLib and JCreator are installed in certain directories is removed, thanks to the use of a new installer. Enjoy, Rijk-Jan van Haaften

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FW: Another H'98 Report query
by Simon Peyton-Jones 13 Feb '02

13 Feb '02

Folks There was a short thread relating to Malcolm's proposal, below. The tenor of the discussion was that indeed his proposal makes sense. It excludes no programs, and makes the language more consistent. I propose to adopt it. Simon -----Original Message----- From: Malcolm Wallace [mailto:Malcolm.Wallace@cs.york.ac.uk] Sent: 31 January 2002 11:08 To: Haskell list Subject: Another H'98 Report query The revised H'98 Report, in the section on Modules, 5.2 (Export Lists), under the description of the forms T (c_i,...) and C (f_i,...) for explicitly named constructors, fieldnames, and methods of the respective type or class, says: The subordinate names c_i (f_i) must not contain duplicates. Yet later in the text it is stated that Exports lists are cumulative: the set of entities exported by an export list is the union of the entities exported by the individual items of the list. I see no reason to disallow duplicates at the subordinate level if they are permitted otherwise. Examples: module M (T,T(C))) where -- legal module M (T(),T(C))) where -- legal module M (T(C),T(C))) where -- legal module M (T(C,C)) where -- illegal I propose we should drop the text that disallows duplicates, to make the last example legal. Regards, Malcolm _______________________________________________ Haskell mailing list Haskell(a)haskell.org http://www.haskell.org/mailman/listinfo/haskell

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Haskell 98 lexical syntax again
by Simon Peyton-Jones 13 Feb '02

13 Feb '02

To meet Ian's observation below, I propose to replace the lexical production newline -> a newline (system dependent) by newline -> return linefeed | return | linefeed which, given maximal munch, will behave decently on any normal system. Any objections? Simon | -----Original Message----- | From: Ian Lynagh [mailto:igloo@earth.li] | The report says | | whitechar -> newline | return | linefeed | vertab | formfeed | | space | tab | uniWhite | newline -> a newline (system dependent) | return -> a carriage return | linefeed -> a line feed | | so, if your system defines a newline to be a line feed, an | implementation is free to choose whether to lex a line feed | as a whitechar or a newline, which makes quite a difference | when you consider the layout rule! | | newline can't be arbitrarily determined by the system - | certainly "x" or "let" would not be acceptable - and having | it system dependent means that Haskell scripts are not | portable between different systems. I haven't looked but I | would be surprised if current implementations behaved | differently on different platforms - I assume they all look | for something matching (<CR><LF>?)|<LF> everywhere.

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Sendind mail
by Monique Louise 13 Feb '02

13 Feb '02

Hi, I'd like to know if there's any Hugs compatible library with functionalities to send mail.

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