The REXX (Restructured Extended Executor) language is designed for systems applications but has many similarities to more familiar languages such as FORTRAN and Pascal. Thus REXX procedures consist of a series of statements embodying variables, literals, and operators as well as an extensive list of built-in functions. DO loops and conditional statements provide sequence control, and the language even contains a GOTO, although it sneaks in under the less informative name of SIGNAL, GOTO presumably still being considered untouchable.

With systems applications in mind, the functions provided are concerned with text processing rather than with numeric applications. REXX also includes a useful PARSE facility and provides for stack operations. Procedures and functions can also be defined by the user.

REXX is an IBM-sponsored language and is interpretive, which means that it is best suited for development work and one-off jobs. As in ALGOL, no standard input/output procedures are provided, and some features of the language are environment-dependent. For this reason, a prospective user would require further information on the particular system where REXX is used, but I can recommend this book as a clear and useful general account of what seems to be a powerful language.