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Programming with REXX , 2 Days

This course covers all aspects of programming with REXX. During the course the student is taught how to write programs that issue TSO commands, read and write to OS/390 datasets, access the REXX Datastack, manipulate string data, perform conditional logic and use functions.

Pre-requisites

The delegate should be familiar with the OS/390 host environment, together with a working knowledge TSO / ISPF.

Course Objectives

The aim of this course is to provide the programmer with the necessary skills required to design, write, code and test REXX programs that interact with TSO.

On completion of this course the student will be able to:

• develop Structured REXX Programs
• understand and use REXX Verbs
• use conditional logic in a REXX program
• use REXX parsing commands
• access the Data Stack
• use REXX to access datasets
• use REXX to run TSO commands
• Develop and use REXX Functions
• interactively test and debug REXX programs

Course Environment

Development will be performed using REXX running on an OS/390 Platform.

Course Details

INTRODUCTION

What is REXX?
Building REXX Programs
On-line Execution of REXX Programs
Batch Execution of REXX Programs
System Definition of REXX Programs
Commencing a REXX Program - Comments
Terminating a REXX Program - Exit

VARIABLES

Assigning Values to Variables
Use of Quotation Marks
Compound Variables (Arrays)
Re-Initialising Variables - Drop
Concatenating Variables
Sending Data to the Terminal - Say
Receiving Data from the Terminal - Pull
Statement Continuation
Variables and Arithmetic
Numbers Supported
Altering Precision
Altering Precision for Comparisons
Interpret

TEXT PARSING

Parsing Words Separated by Spaces
Parsing Words Separated by a Given String
Parsing Words by Specific Columns
Disregarding Portions of a String
Parsing Instructions Summary
Splitting Data using ARG

PROGRAM FLOW AND CONTROL

Conditionally Testing Variables - If / Then / Else
Nested If Statements
Multiple Conditional Testing - The Select Statement
Comparison Operators
Combining Comparisons - Logical Operators
Program Loops
Do
Do Forever
Do While
Do Until
Iterate
Using Leave / Iterate Within Nested Loops
Endless Loops

THE DATA STACK

Datastack Manipulation
Queuing
Stacking
MAKEBUF and DROPBUF
NEWSTACK and DELSTACK
Data Stack Query Commands

SUBROUTINES

Passing Data between Programs
Sending Arguments to External Subroutines
Receiving Arguments into External Subroutines
Receiving Arguments into Main Line Programs
Sharing and Protecting Internal Variables
Returning External Data to the Calling Program
Label Look-Aside Table

FUNCTIONS

Supplied Built-In Functions
User Defined Functions
Subroutine / Function Search Order

TSO INTERFACE

Executing TSO Commands
Allocating Datasets
Freeing Datasets
Renaming Datasets
Deleting Datasets
Clearing the Screen
Dataset Manipulation - The EXECIO Command
Reading Records into the Data Stack
Reading Records into a Compound Variable
Writing Records from the Data Stack
Writing Records from a Compound Variable
Appending Data to a File
Copying a Dataset
Return Codes
Coding Efficient Commands
Suppression of System Messages
The Address Command

PROGRAM TESTING

Trapping Errors
Signal
Trace

Course Format

The course contains many practical exercises to ensure familiarity with the product. Students create REXX programs that interact with TSO. On completion of this course students will be ready to start the development of REXX application programs.

The comprehensive Student Guide supplied is fully indexed serving as a useful reference tool long after the course has finished. Delegates will also be able to access a free help-line with technical questions relating to topics covered on the course.

For further details and booking enquiries, telephone: 01275 859666 or visit:: www.casetraining.co.uk

Contact Case Training