Intended to supplement the material the programmer uses to learn the REXX language, this book is not so much an exposition of “advanced techniques” as a collection of essays on questions that the author, as a teacher of REXX, has found troublesome to his students. The questions have been organized into four parts: coding techniques, program debugging, editor macros (an application of REXX), and user issues.

The most useful of these parts is that on debugging. It includes a description of the REXX TRACE facility, a suggested methodology for debugging REXX programs, a discussion of REXX program performance in the VM environment, and analyses of some 25 REXX instructions that give the intended use of each instruction and examples of errors commonly made in using it. This part will be useful not only to REXX users but to REXX (and other) language architects as well, for the insights it provides into language features that are difficult to use correctly.

The next most useful part is the material on editor macros, which presents a dozen or so macro definitions for common editing tasks such as inserting and deleting fields from a set of records. The range of the examples is limited, but should suffice for the intended audience.

The part on coding techniques offers guidelines for formatting REXX programs (such as indenting conventions) and program organization (such as internal versus external routines). A chapter on “Programming Tricks” poses the common programming problem of returning the position of a given character string in an ordered list of valid strings and gives two REXX fragments which almost but do not quite do the job. The chapter ends abruptly without giving the solution (use the REXX WORDPOS function), suggesting that text was inadvertently omitted.

The part on user issues contains a discussion of eight programming problems, only two of which (“Handling Input Arguments” and “Displaying Sparsely Populated Tables”) involve the user in the usual sense of the term. The rest have to do with achieving some programming capability that REXX does not support directly (such as simulating “include” files), or that is supported via operating system services (such as reading and writing files). A chapter on “Using SELECT in Place of IF” is not REXX-specific and thus is out of place. Included in the list of questions to be addressed in this part is “How can I store my REXX programs?” but the chapter that answers the question has apparently been omitted.

Apart from these lapses, the material is competently and imaginatively presented. The book’s only major fault is that it does not contain more material, particularly in the area of REXX applications.