Rexx tutorial mainframe - What is REXX ?
What is REXX ?
REXX (REstructured eXtended eXecutor) is an interpreted programming language that is extremely versatile. REXX language runs on all platforms like Windows, Z/OS, Linux.etc. REXX language is designed by Michaek Cowlishaw of IBM UK Laboratories.
This tutorial is designed mainly for the REXX mainframe developers.
The following are the features of the REXX language..
Features of REXX
Ease Of use:
The REXX language is easy to read and write because many instructions are meaning English words. Example instructions are SAY, IF, THEN, ELSE, DO, EXIT..etc.
Format Free Language:
There are only few rules in REXX language when compared with other programming languages. REXX doesn’t have rules like an instruction has to start at a particular column. We can write multiple instructions in a single line. Variables don’t need to be predefined. Can allow the instructions in Upper or Lower or mixed cases.
REXX has a built-in functions that performs various arithmetic calculations, comparison operations on both TEXT and NUMBERS, ..etc.
When a REXX programming is running in TSO/E environment and it encounters an error, message describing the error will be displayed on the screen. REXX also has the instruction called TRACE to locate errors at run time.
REXX is an interpreted Language:
Interpreted language is programming language in which programs are executed by an interpreter program(No compilation is done. Only execution). In compiled language like C, COBOL ..etc first the program is converted into the machine understandable code then this machine understandable code will be read by host CPU to execute.