z/OS Version 2 Release 3 TSO/E REXX User's Guide IBM SA32-0982-30 Note Before using this information and the product it supports, read the information in “Notices” on page 193. This edition applies to Version 2 Release 3 of z/OS (5650-ZOS) and to all subsequent releases and modifications until otherwise indicated in new editions. Last updated: 2019-02-16 © Copyright International Business Machines Corporation 1988, 2017. US Government Users Restricted Rights – Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. Contents List of Figures....................................................................................................... ix List of Tables........................................................................................................ xi About this document...........................................................................................xiii Who should use this document.................................................................................................................xiii How this document is organized............................................................................................................... xiii Terminology..........................................................................................................................................xiii Purpose of each chapter...................................................................................................................... xiii Examples.............................................................................................................................................. xiv Exercises.............................................................................................................................................. xiv Where to find more information................................................................................................................ xiv How to send your comments to IBM......................................................................xv If you have a technical problem.................................................................................................................xv Summary of changes...........................................................................................xvi Summary of changes for TSO/E for Version 2 Release 3 (V2R3) and its updates................................... xvi Summary of changes for TSO/E for Version 2 Release 2 (V2R2) and its updates................................... xvi z/OS Version 2 Release 1 summary of changes....................................................................................... xvi Part 1. Learning the REXX Language.......................................................................1 Chapter 1. Introduction............................................................................................................................... 3 What is REXX?.........................................................................................................................................3 Features of REXX.................................................................................................................................... 3 Ease of use........................................................................................................................................ 3 Free format........................................................................................................................................3 Convenient built-in functions........................................................................................................... 3 Debugging capabilities......................................................................................................................3 Interpreted language........................................................................................................................ 4 Extensive parsing capabilities.......................................................................................................... 4 Components of REXX..............................................................................................................................4 The SAA Solution.................................................................................................................................... 4 Benefits of Using a Compiler..................................................................................................................5 Improved Performance.....................................................................................................................5 Reduced System Load.......................................................................................................................5 Protection for Source Code and Programs....................................................................................... 5 Improved Productivity and Quality...................................................................................................5 Portability of Compiled Programs.....................................................................................................6 SAA Compliance Checking................................................................................................................6 Chapter 2. Writing and Running a REXX Exec............................................................................................. 7 Before You Begin.................................................................................................................................... 7 What is a REXX Exec?............................................................................................................................. 7 Syntax of REXX Instructions.................................................................................................................. 8 The Character Type of REXX Instructions........................................................................................ 8 The Format of REXX Instructions..................................................................................................... 9 Types of REXX Instructions............................................................................................................ 11 Execs Using Double-Byte Character Set Names................................................................................. 13 Running an Exec................................................................................................................................... 14 Running an Exec Explicitly..............................................................................................................14 Running an Exec Implicitly............................................................................................................. 15 iii Interpreting Error Messages................................................................................................................ 17 Preventing Translation to Uppercase...................................................................................................18 From Within an Exec....................................................................................................................... 18 As Input to an Exec.........................................................................................................................18 Passing Information to an Exec........................................................................................................... 19 Using Terminal Interaction............................................................................................................. 19 Specifying Values when Invoking an Exec..................................................................................... 19 Preventing Translation of Input to Uppercase............................................................................... 21 Passing Arguments......................................................................................................................... 21 Chapter 3. Using Variables and Expressions.............................................................................................23 Using Variables.....................................................................................................................................23 Variable Names...............................................................................................................................23 Variable Values............................................................................................................................... 24 Exercises - Identifying Valid Variable Names................................................................................ 25 Using Expressions................................................................................................................................ 25 Arithmetic Operators...................................................................................................................... 25 Comparison Operators....................................................................................................................28 Logical (Boolean) Operators...........................................................................................................31 Concatenation Operators............................................................................................................... 32 Priority of Operators......................................................................................................................