------------------------------------------------------- Minutes of meeting ISO/IEC JTC1 SC22 WG17 N195 ------------------------------------------------------- WG17 (Prolog) meeting, 21st August 2006. Seattle, WA. USA. Jonathan Hodgson ISO/IEC JTC1 SC22 WG17 (Prolog) Convener 0.1 Annexes A --- Resolutions. B --- Address list. 1. Attendance. Klaus Daessler(Germany) , Bart Demoen*(Belgium), Pierre Deransart (France) , Remy Haemmerle+ (France), Jonathan Hodgson (Chair), Paulo Moura (Portugal) , Katsuhiko Nakamura (Japan) , Roger Scowen (UK) , Peter Szabo (Hungary) , Peter Szeredi (Hungary) , Neng-Fu Zhou* (USA). + Morning only * Afternoon Only See Annex B for address list. 2 Agenda for meeting -- N193 The agenda as revised was adopted. 3 Drafting committee WG17 decided that a drafting committee was not required for this meeting. Jonathan Hodgson agreed to serve as secretary. 4 Minutes of the Sitges meeting (WG17 N183 ) The minutes of the Sitges meeting were approved. 5. Update on status of ballots. The ballot on the proposed TR on DCGs appears to have passed. Five P members (Germany, Holland, Japan, UK and USA) having agreed to participate. The ballot on Corrigenda 1 through 28 closes on Aug 25th. Members were asked to ensure that their national bodies register a vote. To address the issue of the number of O members who are willing to participate in work items WG17 reached an agreement (Resolution A 1) to seek a modification of the JTC1 directives to permit the vote of O members willing to actively participate to be weighed in ballots on new work items. 6. Discussion of new directions. It was agreed that WG17 would consider possible work on Multi-threading and on Unicode. WG17 reached an agreement (resolution A 2) to ask Portugal to prepare a list of corrigenda to address the omission of certain common predicates from part 1. Amongst these are compare/3, callable/1, forall/2, number_vars/3, retractall/1, sort/2, keysort/2, ground/1, member/2, append/3 and length/2. Appropriate functionalities of predicate_property/2 should be added to part 1. as well. 7. Discussion of the Japanese Proposal on Globals and Arrays. WG17 decided (resolution A 3) that Japan should revise its proposal. Rather than considering globals and arrays the proposal should concern "mutable" or "assignable" variables. Specific issues considered were: - arrays, any way of handling arrays should not require a new data type. - non backtrackable globals, as assert provides this functionality these can for the moment be omitted; - how are such variables typed, this relates to term ordering; - what is the scope of such variables as related to the module system. 8. Definite Clause Grammars. The Portuguese WG recommends that the TR not require that expanding a DCG add exactly two arguments. It further recommends that the predicates expand_term and term_expansion also not be part of the TR. WG17 considered the German comments (N194) on the draft proposal by Portugal. It was resolved (Resolution A 4) to ask Portugal to prepare a new draft for WG17's consideration. 9. Corrigenda. WG17 discussed in detail items 29-37 on Roger Scowen's list (N190) of corrigenda. Discussion of items 38-60 was referred (resolution A 5) to an email discussion. Roger Scowen was requested (resolution A 6) to prepare corrigenda for items 29-60 by January 15th 2007. 10. Multi-threading. Paulo Moura presented a proposal to add multi-threading to the Prolog standard. WG17 agreed (resolution A 7) to pursue the idea. 11. Cyclic terms. Paulo Moura raised the issue of determining whether a term is cyclic for those Prologs that permit non STO unification. It was agreed (resolution A 8) to add, via a defect report and corrigendum, a read only flag "unification" that could have the values cyclic, fail, unsafe that would permit a Prolog implementation to disclose its behaviour with respect to STO unification. 12. Unicode. WG17 discussed the desirability of adding Unicode support to the standard. It was agreed (resolution A 9) to ask for a draft proposal. 13. Next meeting. WG17 asked Paulo Moura to host its next meeting in conjunction with ICLP 2007 in Oporto. 14. The meeting adjourned at 4:55pm A. Resolutions. A 1. WG17 instructs its convener to request of SC22 that a way be found, perhaps by changing the JTC 1 directives, to incorporate the willingness of O members of SC22 to participate actively when counting ballots on new work items. Individuals: Unanimous. Countries: Unanimous. A 2. WG17 asks that by September 30th 2006 Portugal identify and define a set of built-in predicates that have been unreasonably been omitted from part 1 of the standard. Individuals: Unanimous. Countries: Unanimous. A 3. WG17 asks Japan to prepare a report on the addition of mutable objects to Prolog part 1. The report should include: - a survey of how current implementations of Prolog provide this functionality; - consideration of the definition of the semantics of mutable objects compatible with Annex A of part 1; - consideration of the interaction with modules. Individuals: Unanimous. Countries: Unanimous. A 4. WG17 asks Portugal to prepare, by September 30 2006, a revised draft of the TR on DCGS, taking into account the discussion at this meeting. Individuals: Unanimous. Countries: Unanimous. A 5. WG17 asks all members to provide comments on defects 38 through 60 by September 30th 2006. Individuals: Unanimous. Countries: Unanimous. A 6. WG17 asks Roger Scowen to prepare corrigenda as needed for items 29 through 60 following the discussions by WG17 with a due date of January 15th 2006. Individuals: Unanimous. Countries: Unanimous. A 7. WG17 authorizes Paulo Nunes to act a editor for further exploration of the addition of multi-threading to the Prolog standard. Individuals: Unanimous. Countries: Unanimous. A 8. WG17 asks Paulo Moura and Peter Szeredy to write a defect report and corrigendum to add a read only flag `unification' that would have values cyclic, fail, and unsafe which would permit a Prolog implementation to disclose its behaviour with respect to STO unification. Individuals: Unanimous. Countries: Unanimous. A 9. WG17 asks Jan Wielemaker and Matts Carlsson to draft by January 15th 2007 a proposal to add Unicode to the Prolog standard. Individuals: Unanimous. Countries: Unanimous. A 10. WG17 thanks the organizers of FLoC 2006 and ICLP for their help in arranging this meeting. Individuals: Unanimous. Countries: Unanimous. B. Address List. Klaus Daessler Gesellschaft fur Mathematische Intelligenz Goethestrasse 34 D-01445 Radebeul Germany Tel: +49 351 8365590 E-mail: Klaus.Daessler@t-online.de Bart Demoen Dept. of Computer Science K.U. Leuven, 3001 Leuven, Belgium E-mail bmd@cs.kuleuven.be Pierre Deransart INRIA BP 105 78153 Le Chesnay Cedex France Pierre.Deransart@inria.fr Remy Haemmerle INRIA BP 105 78153 Le Chesnay Cedex France Remy.Haemmerle@inria.fr Jonathan Hodgson Dept. of Math/CSC St. Joseph's University 5600 City Avenue Philadelphia. PA 19131 USA Tel: +1 610 660 1571 Fax: +1 215 473 0001 E-Mail: jhodgson@sju.edu Paulo Moura University of Beira Interior 6200 Covilha Portugal. E-mail: pmoura@di.ubi.pt Professor K Nakamura Faculty of Science and Engineering Tokyo Denki University Hatoyama-machi Saitama-Ken 350-0394 JAPAN Tel: +81 492 96 2911 Fax: +81 492 96 6185 E-Mail: nakamura@k.dendai.ac.jp Roger Scowen, 9 Birchwood Grove, Hampton, Middlesex United Kingdom TW12 3DU Tel: +44 (0)20 8979 7429; E-mail: (1) roger.scowen@npl.co.uk (2) patscowen@waitrose.com Peter Szabo Budapest University of Technology and Econ. Dept. of Computer Science and Information technology Muegyetem RKP. 1. H-1111 Budapest, Hungary Peter Szeredi Budapest University of Technology and Econ. Dept. of Computer Science and Information technology Muegyetem RKP. 1. H-1111 Budapest, Hungary Neng-Fa Zhou The City University of New York 2900 Bedford Avenue, Brooklyn, NY 11210-2889 nzhou@acm.org