SC 22/WG17 Minutes Date of meeting: June 1st 2020 Time of meeting: 17:00 UTC -- 17:45 UTC Participants: - Markus Triska (Austria, substitute for indisposed convenor) - Mark Thom (Canada) - Stefan Kral (Austria) 1. Greeting and introduction of participants, administrativa Convenor Ulrich Neumerkel is indisposed. The group wishes him a speedy recovery. 1.1 Minutes of our 2019 meeting (N280), available via: iso.org/jtc1sc22wg17= -> Navigation Menu, N-Documents List -> N280 No requests for changes. 2 Progress in Prolog systems, discussion of implementation practices and on= going alignment, current areas of interest in the application and implement= ation of Prolog Technical aspects of the discussion include a new, very compact representation of strings as lists of characters, common interfaces for attributed variables, and the performance of conforming extensions and implementation techniques for constraint programming. A clean interface for delimited continuations is being discussed as the basis for tabling extensions (SLG resolution) in new systems. The group expresses hope that newly arising Prolog implementations can benefit from each other due to their strong conformance to the standard. One example that is mentioned: New Prolog libraries that have recently been shared between Scryer Prolog and Tau Prolog. 3. DCGs N279 Postponed since the editor of the DCG draft is indisposed. 4. Corrigenda, Discussion of N273 Drafts for further corrigenda are briefly discussed. 5. New projects and liaisons. In the public sector, there is increased interest in symbolic AI approaches. How can we automate the application of existing laws? NZ government already tries to formulate laws as logic programs. COVID-19 has increased the urgency to easily formalize laws (e.g., eligibility requirements for grants) and to automatically reason about them. Automated decisions must be explainable. Different Prolog systems are beginning to support Unicode programs in incompatible and misaligned ways. It is resolved to work on this topic at the next meeting of WG17. The RuleML community expressed interest in the pure subset of Prolog as an interchange format for rule representation. A clear delineation of the pure subset of Prolog is asked for. Even though Annex A mentions "pure" Prolog, the actual standard does not define it.