ISO/IEC INTERNATIONAL STANDARD 13211-2 First edition 2000-06-01 Information technology Programming languages — Prolog - Part 2: Modules Technologies de I'information — Langages de programmation Prolog - Partie 2: Modules Reference number ISO/IEC 13211-2:2000(E) E( @ ISO/IEC 2000 HS under ted without license from IHS Not for Resale ISO/IEC 13211-2:2000(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this area. Adobe is a trademarkof Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event ?ISO/IEC2000 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56. CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 734 10 79 E-mail [email protected] Web www.iso.ch Printed in Switzerland @ISO/IEC2000-All rightsreserved ermittedwithoutlicense from IHS Not for Resale ISO/IEC 13211-2:2000(E) Contents Page Foreword Introduction vi Scope 1 1.1 Notes 2 Normative reference 1 3 Terms and definitions 1 Compliance 3 4.1 Prolog processor . 3 4.2 Module text 4.3 Prolog goal 4.4 Prolog modules 4.4.1 Prolog text without modules 4.4.2 The module user 4 4.5 Documentation 4.5.1 Dynamic Modules 4.5.2 Inaccessible Procedures Syntax 4 5.1 Module text 4 5.2 Terms 4 5.2.1 Operators Language concepts and semantics 4 6.1 Related terms..... 5 6.1.1 Qualified and unqualified terms 6.2 Module text 6.2.1 Module user 6.2.2 Procedure Visibility 6.2.3 Module interface 6.2.4 Module directives 6.2.5 Module body 6.2.6 6.3 Complete database 6.3.1 Visible database 6.3.2 Examples 6.4 Context sensitive predicates 6.4.1 Metapredicate built-ins . . 6.4.2 Context sensitive built-ins 6.4.3 Module name expansion 6.4.4 Examples:Metapredicates 9 6.5 Converting a term to a clause, and a clause to a term 10 6.5.1 Converting a term to the head of a clause 10 6.5.2 Converting a module qualified term to a body 10 6.5.3 Converting the body of a clause to a term. 11 6.6 Executing a Prolog goal 12 ISO/IEC 2000 - All rights reserved ii Copyright International Organization for Standardization No reproduction or networking permitted without license from IHS Not for Resale IS0/IEC 13211-2:2000(E) 6.6.1 Data types for the execution model 12 6.6.2 Initialization 12 6.6.3 Searching the complete database 13 6.6.4 Selecting a clause for execution. 13 6.6.5 Backtracking . 14 6.6.6 Executing a user-defined procedure: 14 6.6.7 Executing a built-in predicate 14 6.7 Executing a control construct 14 6.7.1 call/1 14 6.7.2 catch/3 15 6.7.3 throw/1 15 6.8 Predicate properties 16 6.9 Flags.. 16 6.9.1 Flag:colon sets callingcontext 16 6.10 Errors 16 6.10.1 Errorclassification 16 Built-in predicates 16 7.1 The format of built-in predicate definitions 16 7.1.1 Type of an argument 16 7.2 Module predicates 16 7.2.1 current module/1 17 7.2.2 predicate property/2 17 7.3 Clause retrieval and information 18 7.3.1 clause/2 18 7.3.2 current predicate/1 19 7.4 Database access and modification 20 7.4.1 asserta/1 20 7.4.2 assertz/1 21 7.4.3 retract/1 21 7.4.4 abolish/1 22 iv ISO/IEC 2000 - All rights reserved Copyright Intemational Organizationfor Standardization No reproduction or networking permitted without license from IHS Not for Resale IS0/IEC 13211-2:2000(E) Foreword ISO (the International Organization for Standar