Chapter 1. Introduction; What Is Rexx; Features Of Rexx; Ease Of Use - IBM TSO/E REXX User Manual

Chapter 1. Introduction

What is REXX? . . . . . . . . . . . . . . . . . . . . . . . . . 3

Features of REXX . . . . . . . . . . . . . . . . . . . . . . . . 3
Components of REXX . . . . . . . . . . . . . . . . . . . . . . . 4
The SAA Solution . . . . . . . . . . . . . . . . . . . . . . . . 4
Benefits of Using a Compiler . . . . . . . . . . . . . . . . . . . . 5
This chapter describes the REXX programming language and some of its features.
What is REXX?
REXX is a programming language that is extremely versatile. Aspects such as
common programming structure, readability, and free format make it a good
language for beginners and general users. Yet because the REXX language can be
intermixed with commands to different host environments, provides powerful
functions and has extensive mathematical capabilities, it is also suitable for more
experienced computer professionals.
The TSO/E implementation of the REXX language allows REXX execs to run in any
MVS address space. You can write a REXX exec that includes TSO/E services and
run it in a TSO/E address space, or you can write an application in REXX to run
outside of a TSO/E address space. For more information, see "Chapter 13. Using
REXX in TSO/E and Other MVS Address Spaces" on page 171.

Features of REXX

In addition to its versatility, REXX has many other features, some of which are:

Ease of use

The REXX language is easy to read and write because many instructions are
meaningful English words. Unlike some lower-level programming languages that
use abbreviations, REXX instructions are common words, such as SAY, PULL, IF...
THEN... ELSE..., DO... END, and EXIT.

Free format

There are few rules about REXX format. You need not start an instruction in a
particular column, you can skip spaces in a line or skip entire lines, you can have
an instruction span many lines or have multiple instructions on one line, variables
© Copyright IBM Corp. 1988, 2001
Ease of use . . . . . . . . . . . . . . . . . . . . . . . . . 3
Free format . . . . . . . . . . . . . . . . . . . . . . . . . 3
Convenient built-in functions . . . . . . . . . . . . . . . . . . . 4
Debugging capabilities
Interpreted language . . . . . . . . . . . . . . . . . . . . . . 4
Extensive parsing capabilities . . . . . . . . . . . . . . . . . . . 4
Improved Performance . . . . . . . . . . . . . . . . . . . . . 5
Reduced System Load . . . . . . . . . . . . . . . . . . . . . 5
Protection for Source Code and Programs . . . . . . . . . . . . . . 6
Improved Productivity and Quality . . . . . . . . . . . . . . . . . 6
Portability of Compiled Programs. . . . . . . . . . . . . . . . . . 6
SAA Compliance Checking . . . . . . . . . . . . . . . . . . . . 6
. . . . . . . . . . . . . . . . . . . . . 4
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