REXX

Course objectives
The students will learn how to efficiently code the Restructured EXtended eXecutor (REXX) language. The course combines theory with practical exercises.
The course covers REXX in general and its use in MVS-OS/390-z/OS & VM and on PC.
The students will learn the principles of logic programming techniques through the use of the REXX language.
After the training the students will be able to call, write and debug REXX programs.

Audience
All people who need to rapidly code efficient REXX programs.
Application programmers, systems programmers, operations analysts, end-users, ....

Prerequisites
REXX is a multi-platform programming language.
Although our course includes the REXX extensions for MVS-OS/390-z/OS and VM-z/VM, the REXX knowledge you will acquire is applicable to any platform.
There are no prerequisites.

Class infrastructure
The students must have access to an OS/390 or z/OS system and logon under TSO, or access to a VM or z/VM system and logon under CMS, or use a PC on which a (free) REXX-interpreter is to be installed.

Course contents

The benefits of using REXX

Classic REXX, SAA REXX, and ANSI REXX

Literal strings

Numbers

Concatenation operators

Variables

REXX special variables: RC, RESULT, and SIGL

Compound symbols

Constant symbols

Arithmetic operators

Comparative operators

Transitivity

NUMERIC instruction

Clauses

Logical operators

Operator precedence

Labels

SIGNAL instruction

CALL instruction

Function call

Arguments string

Running a program under TSO/E

Running a program under CMS

Running a program on a PC

Recursivity

Internal routines, built-in functions, and external routines

IF construct

NOP instruction

Simple DO group

Simple repetitive DO group

Controlled repetitive DO group

Complicated DO group

LEAVE instruction

ITERATE instruction

SELECT group

Commands

ADDRESS instruction

Host command environments

TRACE instruction

TSO/E REXX commands

INTERPRET instruction

Character built-in functions

Arithmetic built-in functions

Writing your own mathematical functions

Exception handling

State built-in functions

Interactive debugging

Fixed-point numbers

Conversion built-in functions

I/O built-in functions

Miscellaneous built-in functions

TSO/E and VM/CMS external functions

DROP instruction

UPPER instruction

PROCEDURE instruction

EXIT instruction

PARSE instruction

Running a program in USS (the UNIX shell under MVS-OS/390-z/OS)

Immediate commands

Terminal read

External data queue

ARG instruction

PULL instruction

PUSH instruction

External data queue buffers

VM/CMS and TSO/E REXX EXECIO command

SAY instruction

Extended MCS console session

VM/CMS and TSO/E external functions

REXX in TSO/E and in non-TSO/E address spaces

Foreground and background processing

etc.