------------------------------------------------------- Minutes of meeting ISO/IEC JTC1 SC22 WG17 N213 ------------------------------------------------------- WG17 (Prolog) meeting, 17 July 2009 Pasadena, California, USA Jonathan Hodgson ISO/IEC JTC1 SC22 WG17 (Prolog) Convener 0.1 Annexes A --- Resolutions. B --- Address list. 1. Attendance. Klaus Daessler(Germany) ,Brian DeVries (US), Mike Elston (New Zealand), Manuel Hermenegildo (Spain), Jonathan Hodgson (Chair),Stanley Jointer (US),Kyle Marple (US), Paulo Moura (Portugal) , Katsuhiko Nakamura (Japan) , Ulrich Neumerkel (Austria), Alexandre Pinto (Portugal), Neda Saeedloei, (US), David S. Warren (US), Jan Wielemaker (Holland), Neng Fa Zhou (US). See Annex B for address list. 2 Agenda for meeting -- N208. It was agreed that the agenda would be modified to allow discussion of the document on core predicates followed by discussion of globals. 3 Drafting committee and secretary WG17 decided that a drafting committee was not required for this meeting. Jonathan Hodgson agreed to serve as secretary. 4. Minutes of the Udine Meeting meeting (WG17 N207) The minutes of the Udine meeting were approved. 5. Paulo Moura led a discussion of the document on core predicates. In a series of resolutions -- A 1,A 2, and A 3, it was decided to retain some of the proposed core predicates, to remove others from the draft and to replace the proposed call_cleanup/2 with setup_call_cleanup/3. Details are in the resolutions. Jonathan Hodgson took an action item to pursue the issue of flags related to floating point arithmetic by consulting with arithmetic experts. Jonathan Hodgson will check with Roger Scowen on the issue of the typo in the error list for 8.9.3.1. A target date of November 1st 2009 was set for revision of the document. 6. Discussion of the Japanese Proposal on Globals and Arrays. Katsuhiko Nakamura introduced the new draft. After some discussion two resolutions were proposed. These involved renaming and requiring that globals and mutable terms be assigned a value at ``creation'' (A 4) and a review of the errors that could be raised along with consideration of a reference implementation (A 5). 7. Ulrich Neumerkel observed that a new error is required to deal with cases where an argument must be a variable when a predicate is called, as happens with open/4 and some of the proposed predicates in the globals/mutable terms document. Ulrich Neumerkel took an action item to prepare a draft on this. 8. Next meeting. The next meeting is to be in Edinburgh in July 2010 co-located with ICLP and FLOC. 11. The meeting adjourned at 5.40 p.m. A. Resolutions. A.1. WG 17 resolves that the core predicates document N208 shall be modified as follows: a. The flag unification_subject_to_occurs_check shall be renamed sto_unification_result with the original values. When the value is ``cyclic'' and unification would require a cyclic term the unification shall terminate. b. The float related flags shall be removed pending the recommendation of arithmetic experts. c. In 8.2.4 the specification of subsumes shall be `General \theta = Specific = Specific \theta'. d. 8.3.9.4 add an example callable(X). e. 8.3.11 Rename this predicate acyclic_term. f. 8.3.12 Remove cyclic. g. 8.9.5 retractall/1 shall be described as a bootstrapped predicate. h. 8.15.4 call/2-N is the subject of resolution A 2. i. 8.15.5 call_cleanup is the subject of resolution A 3. j. 8.18 the list processing predicates append/3, member/2 and length/2 shall be removed as current practice frequently implements them in libraries. k. 9.3.8 log/2 shall be removed. l. 9.6 hyperbolic functions will not be included. m. 9.7.3 shall be omitted pending the advice of arithmetic experts. n. ^/2 shall be used for integer exponentiation. The remaining predicates and flags are to be retained. A revised version to be circulated by November 1st for email comments. Individuals: Unanimous. Countries: Unanimous. A 2. WG 17 resolves that call/2-N of 8.15.4 in N 208 shall require all implementations to support at least an arity of 8 (allowing seven extra arguments). The exact number shall be implementation dependent, with errors determined by the resulting call to a possibly non existent predicate. Individuals: Unanimous. Countries: Unanimous. A 3. WG 17 resolves that 8.15.5 call_cleanup/2 shall be replaced by a predicate setup_call_cleanup/3, which shall be a control construct. The first arguments of this predicate is to be called as though by once. Ulrich Neumerkel shall prepare the new version for inclusion in the revision of N 208. Individuals: Unanimous. Countries: Unanimous. A 4. WG 17 resolves that mutable and global variables shall be `created' with predicates new_mutable/2, create_global/2 and directive global/2 that shall assign values at ``creation'' time. Further is_mutable shall be renamed mutable. Individuals: Unanimous. Countries: Unanimous. A 5. WG 17 asks Japan to prepare a revised version of the globals proposal N 210 taking into account the comments at this meeting and describing the errors that the new predicates may raise. Japan is further asked to use a reference implementation. This revised version to be circulated by November 1st for email comments. Individuals: Unanimous. Countries: Unanimous. A 6. WG 17 asks Ulrich Neumerkel to prepare a proposal on a new error to account for those cases where an argument must not be instantiated when the predicate is called. This draft to be circulated by November 1st for email comments Individuals: Unanimous. Countries: Unanimous. A 7. WG17 thanks the organizers of ICLP 2009 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@mathint.com Brian DeVries, University of Texas at Dallas, bwd06200@utdallas.edu Mike Ekston Scientific Sftware and Systems Limited, New Zealand. Manuel Hermenegildo, herme@fi.upm.es 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 Stanley Jointer. University of Texas at Dallas, sjointer2@utdallas.edu Kyle Marple, University of Texas at Dallas. 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 Ulrich Neumerkel Institut für Computersprachen E185/1 Technische Universität Wien Argentinierstraße 8/4 A-1040Wien Austria ulrich@complang.tuwien.ac.at Alexandre Pinto, FCT_Universidad Nova de Lisboa, Portugal, amp@di.fct.unl.pt Neda Saeedloei, University of Texas at Dallas nxs048000@utdallas.edu David S. Warren, davidswarren@gmail.com Jan Wielemaker, HCS, Univ v Amsterdam, Kruislaan 41G Amsterdam The Netherlands E-mail: wielemak@science.uva.nl j.wielemaker.uva.nl Neng-Fa Zhou The City University of New York 2900 Bedford Avenue, Brooklyn, NY 11210-2889 nzhou@acm.org