ISO/IEC INTERNATIONAL STANDARD 7185 Second edition 1990-10-15 Information technology - Programming languages -- Pascal (Revision of ISO 7185 : 1983) Technologies de I'information - Langages de programmation - Pascal (Révision de I'ISO 7185 : 1983) Reference number ISO/IEC 7185:1990 (E) Copyright Intermational Organization for Standardization cense with IS permitted without license from IHS Not for Resale ISO/IEC 7185 : 1990 (E) Contents Page Scope 2 Normative reference 3Definitions 1 4 Definitional conventions 2 5 Compliance 3 5.1 Processors 3 5.2 Programs 5 6 Requirements 5 6.1 Lexicaltokens. 5 6.2 Blocks, scopes and activations 8 6.3 Constant - definitions . 11 6.4 Type - definitions . 11 6.5 Declarations and denotations of variables 21 6.6 Procedureandfunctiondeclarations 24 6.7 Expressions. 38 6.8 Statements 42 6.9 Input andoutput 49 6.10 Programs 55 Annexes A Collected syntax . 58 B Cross - references 64 c Required identifiers 71 Errors. 72 E Implementation - defined features 76 Implementation - dependent features 78 ? ISO/IEC1990 All rights reserved. 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 the publisher. ISO/IEC Copyright Office . Case postale 56 . CH-1211 Geneve 20 . Switzerland Printed in Switzerland ii Copyright Intermational Organization for Standardization se from IHS Not for Resale ISO/IEC7185:1990(E) Foreword ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardiz- ation. National bodies that are members of ISO or IEC participate in the development of International Standards through technical committees established by the respective organization to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information technology, ISO and IEc have established a joint technical committee, ISO/IEC JTC 1. Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote. International Standard ISO/iEC 7185 5 was prepared by Joint Technical Comraittee ISO/IEC JTC 1, Information technology. This second edition cancels and replaces the first edition (ISo 7185 : 1983). Annexes A, B, C, D, E and F are for information. ili Copyright Intemational Oorganizatin for Standardization No repr ermitted without license from IHS Not for Resale ISO/IEC 7185:1990(E) Introduction This International Standard provides an unambiguous and machine independent definition of the wide variety of data processing systems. Language history The computer programming language Pascal was designed by Professor Niklaus Wirth to satisfy two principalaims a) to make available a language suitable for teaching programming as a systematic discipline based on b) to define a language whose implementations could be both reliable and efficient on then-available computers. However, it has become apparent that Pascal has attributes that go far beyond these original goals. It is now being increasingly used commercially in the writing of both system and application software. This International Standard is primarily a consequence of the growing commercial interest in Pascal and the need to promote the portability of Pascal programs between data processing systems. In drafting this International Standard the continued stability of Pascal has been a prime objective. However, apart from changes to clarify the specification, two major changes have been introduced. a) The syntax used to specify procedural and functional parameters has been changed to r