This book unifies a broad range of programming language concepts under the framework of type systems and structural operational semantics.

A new edition of a textbook that provides students with a deep, working understanding of the essential concepts of programming languages, completely revised, with significant new material. This book provides students with a deep, working understanding of the essential concepts of programming languages. Most of these essentials relate to the semantics, or meaning, of program elements, and the text uses interpreters (short programs that directly analyze an abstract representation of the program text) to express the semantics of many essential language elements in a way that is both clear and executable. The approach is both analytical and hands-on. The book provides views of programming languages using widely varying levels of abstraction, maintaining a clear connection between the high-level and low-level views. Exercises are a vital part of the text and are scattered throughout; the text explains the key concepts, and the exercises explore alternative designs and other issues. The complete Scheme code for all the interpreters and analyzers in the book can be found online through The MIT Press web site. For this new edition, each chapter has been revised and many new exercises have been added. Significant additions have been made to the text, including completely new chapters on modules and continuation-passing style. Essentials of Programming Languages can be used for both graduate and undergraduate courses, and for continuing education courses for programmers.

" .. .1 always worked with programming languages because it seemed to me that until you could understand those, you really couldn't understand computers. Understanding them doesn't really mean only being able to use them. A lot of people can use them without understanding them." Christopher Strachey The development of programming languages is one of the finest intellectual achievements of the new discipline called Computer Science. And yet, there is no other subject that I know of, that has such emotionalism and mystique associated with it. Thus, my attempt to write about this highly charged subject is taken with a good deal of in my role as professor I have felt the need for a caution. Nevertheless, modern treatment of this subject. Traditional books on programming languages are like abbreviated language manuals, but this book takes a fundamentally different point of view. I believe that the best possible way to study and understand today's programming languages is by focusing on a few essential concepts. These concepts form the outline for this book and include such topics as variables, expressions, statements, typing, scope, procedures, data types, exception handling and concurrency. By understanding what these concepts are and how they are realized in different programming languages, one arrives at a level of comprehension far greater than one gets by writing some programs in a xii Preface few languages. Moreover, knowledge of these concepts provides a framework for understanding future language designs.

Fundamentals of Computer by Saurabh Agrawal is a publication of the SBPD Publishing House, Agra. In the present time, the Computer is an integral part of our lives. Much of the work we do now involves computers in one way or the other. Thanks to this piece of machinery, the world has shrunk into a global village. It gives the author great pleasure in presenting the First Edition of this book Fundamentals of Computer in the hands of students and their esteemed Professors. The present book targets to meet in full measure the requirements of students preparing for B.B.A., B.Com. and other Professional Courses of various Indian Universities. Salient features of this book are as follows- 1. The motto of this book is to provide the easy and obvious understanding of the subject to the students. 2. Every best effort has been made to include the questions asked in various examinations in different years. 3. The subject matter of this book is prepared scientifically and analytically. 4. Volume of the book and size of different topics have been kept keeping in view to meet out the need for examinations.