The title of this book contains the words ALGORITHMIC LANGUAGE, in the singular. This is meant to convey the idea that it deals not so much with the diversity of program ming languages, but rather with their commonalities. The task of formal program develop It allows classifying ment proved to be the ideal frame for demonstrating this unity. concepts and distinguishing fundamental notions from notational features; and it leads immediately to a systematic disposition. This approach is supported by didactic, practical, and theoretical considerations. The clarity of the structure of a programming language de signed according to the principles of program transformation is remarkable. Of course there are various notations for such a language. The notation used in this book is mainly oriented towards ALGOL 68, but is also strongly influenced by PASCAL - it could equally well have been the other way round. In the appendices there are occa sional references to the styles used in ALGOL, PASCAL, LISP, and elsewhere."

The title of this book contains the words ALGORITHMIC LANGUAGE, in the singular. This is meant to convey the idea that it deals not so much with the diversity of program ming languages, but rather with their commonalities. The task of formal program develop It allows classifying ment proved to be the ideal frame for demonstrating this unity. concepts and distinguishing fundamental notions from notational features; and it leads immediately to a systematic disposition. This approach is supported by didactic, practical, and theoretical considerations. The clarity of the structure of a programming language de signed according to the principles of program transformation is remarkable. Of course there are various notations for such a language. The notation used in this book is mainly oriented towards ALGOL 68, but is also strongly influenced by PASCAL - it could equally well have been the other way round. In the appendices there are occa sional references to the styles used in ALGOL, PASCAL, LISP, and elsewhere."

This book is the second of two volumes that present the main results which emerged from the project CIP - "C"omputer-Aided, "I"ntuition-Guided "P"rogramming - at the Technical University of Munich. Its central theme is program development by transformation, a methodology which is becoming more and more important. Whereas Volume I contains the description and formal specification of a wide spectrum language CIP-L particularly tailored to the needs of transformational programming, Volume II serves a double purpose: First, it describes a system, called CIP-S, that is to assist a programmer in the method of transformational programming. Second, it gives a non-toy example for this very method, since it contains a formal specification of the system core and transformational developments for the more interesting system routines. Based on a formal calculus of program transformations, the informal requirements for the system are stated. Then the system core is formally specified using the algebraic data types and the pre-algorithmic logical constructs of the wide spectrum language CIP-L. It is demonstrated how executable, procedural level programs can be developed from this specification according to formal rules. The extensive collection of these rules is also contained in the book; it can be used as the basis for further developments using this method. Since the system has been designed in such a way that it is parameterized with the concrete programming language to be transformed, the book also contains a guide how to actualize this parameter; the proceeding is exemplified with a small subset of CIP-L.

herrschen. Bedeutsam ist auch die Abgrenzung der dritten Ebene, der Ebene der verselb- standigten Variablen und Zeiger. Der vergleichsweise geringe Umfang von Kap. 7 bedeutet einerseits, dass die Beschreibung sich auf Grundsatzliches beschrankt, dem sich viele aus der Literatur der Systemprogrammierung bekannte Einzelheiten unterordnen, beispiels- weise aus D. E. Knuth's, The Art of Computer Programming' oder G. Seegmullers, Ein- fuhrung in die Systemprogrammierung', andererseits aber auch, dass die Vervollstandi- gung der theoretischen Grundlagen noch aussteht. Zu den einzelnen Abschnitten dieses Buches gibt es einen Hintergrund unterschiedlich weit entwickelter mathematischer Theorien. Wichtige Grundbegriffe sind verbandstheore- tischer Natur. Die fundamentalen Arbeiten von D. Scott haben das eindrucksvoll bewie- sen. Bei den Rechenstrukturen des 3. Kapitels steht die moderne Theorie der universellen Algebra im Hintergrund, insbesondere Arbeiten von Birkhoff und Tarski sind hier von Be- deutung. Da wir kein mathematisches Lehrbuch vorlegen, mussen wir uns meistens mit Andeutungen und Hinweisen begnugen. Das Buch hat sich aus Vorlesungen und begleitenden UEbungen entwickelt, die in den letz- ten Jahren an der Technischen Universitat Munchen gehalten wurden. Es entstand in enger Wechselwirkung mit dem Projekt CIP ("Computer-aided Intuition-guided Programming") und dem Teilprojekt "Breitbandsprache und Programmtransformation" im Sonderfor- schungsbereich 49, Programmiertechnik, an der Technischen Universitat Munchen. Bei dem Versuch, fur ein einigermassen abgerundetes, geschlossenes Lehrgebaude der Programmie- rung die Fundamente zu legen, musste vieles fragmentarisch bleiben. In manchen Punkten war es notwendig, Positionen zu beziehen, die auf den ersten Blick unkonventionell erschei- nen moegen, um Erstarrungen zu loesen und einseitige Doktrinen zu korrigieren.