The new version of Fortran, revised to meet new concepts in programming and programming methodology, is described in detail. Each chapter is devoted to a grammatical concept, starting with the alphabet and the two source forms (fixed and free). The second chapter describes primitive Fortran types, derived types, and structure objects. Chapter 3 covers lexical tokens (keywords, names, operators, and constants). Data objects include character substrings and arrays, whose inner structure is described in chapter 4. Pointers, discussed in chapter 5, are not data types but attributes, so their definition is mainly semantic. This also holds for arrays, the subject of chapter 6. Expressions, covered in chapter 7, may be numeric, relational, logical, or of character type. New operators may be defined. Chapter 8 is about assignments. Chapter 9 covers declaration and attribute specification statements. Control statements (selection, iteration, and the case statement) are given in chapter 10. Input/output and files are discussed in chapter 11, and formats in chapter 12. The last two chapters describe program units, subprograms, and intrinsic subprograms.

This book answers any question you may have about any detail of Fortran 90, at either the syntactic or the semantic level. In the preface, Gehrke says, “the standard document is a reference book for compiler writers and those experts who already know all about Fortran 90, but is useless for beginners and rather impractical even for experienced programmers. The Fortran 90 language guide is intended to serve as a language reference manual for programmers, as teaching material for introductory courses in Fortran programming, and as a help for experienced Fortran 77 programmers migrating to Fortran 90.” I am not convinced that he has achieved all of these objectives.

Clearly, this book can be used as a reference, but you cannot learn a language by reading its grammar. You first learn to say simple things in the language, and the grammar comes later. I can imagine that good Fortran programmers will be able to use this book to identify the new facilities in Fortran 90, but I am not sure they will easily master them. This book lacks examples showing how to say things in Fortran 90. As a programming teacher of many years, I could use this book to prepare my lectures, but I would not recommend it to my students. They could use it to answer questions about the exact effect of some construction or about the precedence of operators, but not to discover how to write a good and readable program. It contains no stylistic considerations, nothing that could help a beginner to choose the best way to express a given computation. Moreover, there are unacceptable confusions. A subprogram is a statement, and a function is an expression. They are different in nature; they act differently. A function computes a result from its data, while a subprogram may change the value of some argument; it acts like an assignment. I do not like the chapter that considers a function as a special case of a subprogram.

This book can be recommended to Fortran programmers who need a thorough knowledge of Fortran 90. For this audience, it is an excellent and readable reference book, with a good index.