Language history

Pascal

ISO 7185:1990

This online copy of the unextended Pascal standard is provided only as an aid to standardization. In the case of differences between this online version and the printed version, the printed version takes precedence.

Do not modify this document. Do not include this document in another software product. You may print this document for personal use only. Do not sell this document.

Use this information only for good; never for evil. Do not expose to fire. Do not operate heavy equipment after reading, may cause drowsiness. Do not read under the influence of alcohol (although there have been several unconfirmed reports that alcohol actually improves the readability). The standard is written in English. If you have trouble understanding a particular section, read it again and again and again... Sit up straight. Eat your vegatables. Do not mumble.

© ISO/IEC 1991

ISO/IEC 7185:1990(E)

Acknowledgements

The efforts are acknowledged of all those who contributed to the work of the BSI and ISO Pascal working groups, and in particular:

Tony Addyman Harris Hall John Reagan

Albrecht Biedl Carsten Hammer Mike Rees

Bob Brewer Atholl Hay Arthur Sale

Coen Bron Tony Hetherington Paula Schwartz

David Burnett-Hall Steve Hobbs Barry Smith

David Bustard Mel Jackson John Souter

Barry Byrne Scott Jameson Manfred Stadel

Klaus Daessler David Jones Bob Tennent

Richard De Morgan David Joslin Tom Turba

Norman Diamond Katsuhiko Kakehi Eiiti Wada

Bob Dietrich Olivier Lecarme Willem Wakker

Ken Edwards Jim Miner David Watt

Jacques Farr'e Wes Munsil Jim Welsh

Bill Findlay Bill Price Brian Wichmann

The efforts are acknowledged of all those who contributed to the work of JPC, and in particular:

Michael Alexander Steven Hobbs David L. Presberg

Jeffrey Allen Albert A. Hoffman William C. Price

Ed Barkmeyer Robert Hutchins Bruce Ravenal

W. Ashby Boaz Rosa C. Hwang David L. Reese

Jack Boudreaux Scott Jameson David C. Robbins

A. Winsor Brown David Jones Lynne Rosenthal

Jerry R. Brookshire Steen Jurs Tom Rudkin

Tomas M. Burger Mel Kanner Stephen C. Schwarm

David S. Cargo John Kaufmann Rick Shaw

Richard J. Cichelli Leslie Klein Carol Sledge

Joe Cointment Bruce Knobe Barry Smith

Roger Cox Dennis Kodimer Rudeen S. Smith

Jean Danver Ronald E. Kole Bill Stackhouse

Debra Deutsch Alan A. Kortesoja Marius Troost

Bob Dietrich Edward Krall Thomas N. Turba

Victor A. Folwarczny Robert Lange Prescott K. Turner

G. G. Gustafson Rainer McCown Howard Turtle

Thomas Giventer Jim Miner Robert Tuttle

Hellmut Golde Eugene N. Miya Richard C. Vile, Jr

David N. Gray Mark Molloy Larry B. Weber

Paul Gregory William Neuhauser David Weil

Michael Hagerty Dennis Nicholson Thomas R. Wilcox

Charles E. Haynes Mark Overgaard Thomas Wolfe

Christopher Henrich Ted C. Park Harvey Wohlwend

Steven Hiebert Donald D. Peckham Kenneth M. Zemrowski

Ruth Higgins David Peercy

Charles Hill Robert C. B. Poon

(The above list is of people acknowledged in ANSI/IEEE770X3.97-1983.)

ISO/IEC 7185:1990(E)

Introduction

This International Standard provides an unambiguous and machine independent definition of the programming language Pascal. Its purpose is to facilitate portability of Pascal programs for use on a wide variety of data processing systems.

Language history

The computer programming language Pascal was designed by Professor Niklaus Wirth to satisfy two principal aims

a) to make available a language suitable for teaching programming as a systematic discipline based on certain fundamental concepts clearly and naturally reflected by the language;

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 require the use of a procedure or function heading, as appropriate (see 6.6.3.1); this change was introduced to overcome a language insecurity.

b) A fifth kind of parameter, the conformant-array-parameter, has been introduced (see 6.6.3.7). With this kind of parameter, the required bounds of the index-type of an actual-parameter are not fixed, but are restricted to a specified range of values.

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