Job Control Language (Wiley Self-teaching Guide). Ruth Ashley and Judi N. Fernandes, with Gary Deward Brown. New York: John Wiley & Sons, Inc.; 1978: 157 p. Price: $4.95. ISBN: 0-471-03205-0

Abstract

poor documentation for all who must follow. Concerted efforts were made t o eliminate g o to’s, not only from programs written in existing languages, but also from the syntax of newer compilers. As is common with such movements, excesses were committed, and many go to’s were replaced by structures of a “modular” type even when the new construction was convoluted and resulted in programs that executed much more slowly. Enter Knuth, with this thoughtful and eminently readable mean between the extremes. He has succeeded in personalizing his account of the foibles of trying t o program everything without go to’s, and has done so without false modesty or egotism-clearly a tribute t o his writing style. There is, for example, the anecdote about Dr. Eiichi Goto of Japan, who “cheerfully complained that he was always being eliminated” (p. 143). There is also the careful overview of the history of the subject, which shows clearly that the systematic avoidance of g o to’s was advocated as early as 1963 and practiced as early as 1960, whereas Dijkstra’s letter did not appear until 1968! Moreover, while many readers are probably familiar with the use of constructions such as DO WHILE and DO UNTIL, how many know about come f r o m statements-a spoof cited on p. 187?! It is also refreshing to see yet another person of this stature acknowledge that program code can be easier t o follow than many flowcharts. Throughout the text algorithms are given in BNF, Algol, or YL/I, with flowcharts and other diagrams used when appropriate. The book is well prepared and the text is admirably clean, with exceptions that always seem to be the fault of the publisher rather than the authors, e.g., the running head on p. 237 that reads “Formal Definition of the Seamantics” [sic], o r the index entry on p. 272 that identifies a “Conlatenation [sic] operator.” Such lapses are forgivable, however, and the book as a whole is highly recommended to computer scientists and also t o those among us who must teach applications programming.