General information about REXX

REXX is a general purpose programming language, similar to PL/I. It includes extensive parsing capabilities for character manipulation, extensive mathematical capabilities, and numerous built-in functions that perform various processing, searching, and comparison functions.

REXX programs are typically run by a language processor (interpreter). That is, the program is run statement-by-statement, without first being translated to another form (compiled). Because of the interpretive nature of REXX, FM/IMS is able to exploit the power of REXX when processing segment identification and field selection criteria.

Although REXX is a powerful and versatile language, coding selection criteria using REXX is straightforward. You do not need to know how to write REXX programs. All you need to know is how to write REXX comparison expressions. FM/IMS takes care of turning your selection criteria into a REXX program.