The IBM brochure TSO-E REXX Reference, form number SA22-7790 contains the following short description:
The REstructured extended eXecutor (REXX) language is particularly suitable for:
–Application front ends
–User-defined macros (such as editor subcommands)
Individual users can write programs for their own needs.
REXX is a general-purpose programming language like PL/I. REXX has the usual structured-programming instructions – IF, SELECT, DO WHILE, LEAVE, and so on – and a number of useful built-in functions.
The language imposes no restrictions on program format. There can be more than one clause on a line, or a single clause ...