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Programming with REXX and ISPF Dialog Manager, 4 Days

This course covers all aspects of programming with REXX. During the course the student is taught how to write and test programs that issue TSO commands, manipulate MVS datasets and DB2 Tables, access the REXX Datastack, manipulate string data, perform conditional logic and arithmetic, and use functions.

The student is also introduced to ISPF Dialog Management commands and is shown how create applications containing ISPF Panels, Messages, Skeletons and Tables, which interface with REXX EXECS.

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 and ISPF Dialog Manager.

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
• Develop REXX Programs that interface with ISPF Panels, Tables, Messages and Skeleton data
• Develop REXX programs to access DB2 data
• 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

DB2 ACCESS

Setting the Environment
Connecting to a DB2 Subsystem
EXECSQL statement
Rules of SQL
Host Variables
Cursor Processing
Prepare Statement
Null Indicators
SQLCA
Isolation Level

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

DB2 ACCESS

Setting the Environment
Connecting to a DB2 Subsystem
Sample Code
Execsql
SQL Rules
Host Variables
Cursor Processing
Prepare
Null Indicators
SQLCA
Sample Program
Isolation Level

DIALOG MANAGER

ISPF Dialog Manager Services
Dynamic Concatenation Of ISPF Datasets
The Model Command

DIALOG MANAGER PANELS

Panels
Panel Sections
Selection Panels
Data Entry Panels
Pop-Up Panels
The )ATTR Section
The )BODY Section
The )INIT Section
The )PROC Section
The )END Section
Variable Manipulation within Panels
Assignment Statements
The TRUNC (Truncate) Function
The TRANS (Translate) Function
The IF Statement
VER (Verify) Statements
Saving And Retrieving Variables
The Newappl and Newpool Parameters
VPUT And VGET Statements
Displaying A Panel in REXX
Displaying A Pop-Up Panel
Cursor Positioning

DIALOG MANAGER MESSAGES

Message Definitions
Error Message Naming Syntax
Error Message Content
Predefined Messages
Error Message Parameters
Displaying An Error Message in REXX

DIALOG MANAGER TABLES

Dialog Manager Table Services
Creating A Table
Writing To A Table
Table Display - Scrollable Panels
Displaying A Table within a Scrollable Panel
Selecting / Updating The Table Display
Positioning The Pointer
Closing A Table
Table Level Services
Row Level Services

DIALOG MANAGER SKELETONS

Skeleton Members - File Tailoring
File Tailoring Control Statements
File Tailoring Control Characters
The )BLANK Statement
The )CM Statement
The )DEFAULT Statement
The )DOT and )ENDDOT Statements
The )IM Statement
The )SEL and )ENDSEL Statements
The )SET Statement
The )TB Statement
File Tailoring Example

LIBRARY MANAGEMENT SERVICES

Using Library Management Services

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, DB2 and ISPF Dialog Management Services. On completion of this course students will be ready to start the development of REXX / ISPF 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.

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