puter system. In 1971 one computer system had a Pascal compiler. By 1974
the number had grown to 10 and in 1979 there were more than 80. Pascal
is always available on those ubiquitous breeds of computer systems:
personal computers andl professional workstations. Questions arising out
of the Southampton Symposium on Pascal in 1977 [Reference 10] began
the first organized effort to write an officially sanctioned,
international Pascal Standard. Participants sought to consolidate the
list of questions that naturally arose when people tried to implement
Pascal compilers using definitions found in the Pascal User Manual and
Report. That effort culminated in the ISO 7185 Pascal Standard
[Reference 11] which officially defines Pascal and necessitated the
revision of this book. We have chosen to modify the User Manual and the
Report with respect to the Standard - not to make this book a substitute
for the Standard. As a result this book retains much of its readability
and elegance which, we believe, set it apart from the Standard. We
updated the syntactic notation to Niklaus Wirth's EBNF and improved the
style of programs in the User Manual. For the convenience of readers
familiar with previous editions of this book, we have included Appendix
E which summarizes the changes necessitated by the Standard.