A package of letters, drawings and photographs that young "Clary" and her little sister, Ollie, sent to their parents during World War II triggers a flood of repressed memories: from April 1943 to May 1945, they had been hidden by the sister of one of their father's Resistance comrades.

Topics • what this book is about, • its intended audience, • what the reader ought to know, • how the book is organized, • acknowledgements. Specifications express information about a program that is not normally part of the program, and often cannot be expressed in a programming lan guage. In the past, the word "specification" has sometimes been used to refer to somewhat vague documentation written in English. But today it indicates a precise statement, written in a machine processable language, about the purpose and behavior of a program. Specifications are written in languages that are just as precise as programming languages, but have additional capabilities that increase their power of expression. The termi nology formal specification is sometimes used to emphasize the modern meaning. For us, all specifications are formal. The use of specifications as an integral part of a program opens up a whole new area of programming - progmmming with specifications. This book describes how to use specifications in the process of building programs, debugging them, and interfacing them with other programs. It deals with a new trend in programming - the evolution of specification languages from the current generation of programming languages. And it describes new strategies and styles of programming that utilize specifications. The trend is just beginning, and the reader, having finished this book, will viii Preface certainly see that there is much yet to be done and to be discovered about programming with specifications.

Reprint of the original, first published in 1872. The publishing house Anatiposi publishes historical books as reprints. Due to their age, these books may have missing pages or inferior quality. Our aim is to preserve these books and make them available to the public so that they do not get lost.

This reference manual of ANNA is another volume addressed to the ADA community. ANNA is a language extension of ADA to include facilities for formally specifying the intended behavior of ADA programs. It is designed to meet a perceived need to augment ADA with precise machine-processable annotations so that well established formal methods of specification and documentation can be applied to ADA programs. The current ANNA design includes annotations of all ADA constructs except tasking. Similar extensions for formal specification can be made to other Algol-like languages such as Pascal, PL/1, Concurrent Pascal, and Modula; essentially, these extensions would be subsets of ANNA. The design of ANNA was undertaken from the beginning with four principal considerations: 1. Constructing annotations should be easy for the ADA programmer and should depend as much as possible on notation and concepts of ADA. 2. ANNA should possess language features that are widely used in the specification and documentation of programs. 3. ANNA should provide a framework within which the various established theories of formally specifying programs may be applied to ADA. 4. Annotations should be equally well suited for different possible applications during the life cycle of a program. Such applications include not only testing, debugging and formal verification of a finished program, but also specification of program parts during the earlier stages of requirements analysis and program design.