z/VM Version 7 Release 2 REXX/VM Reference IBM SC24-6314-01 Note: Before you use this information and the product it supports, read the information in “Notices” on page 313. This edition applies to Version 7.2 of IBM z/VM (product number 5741-A09) and to all subsequent releases and modifications until otherwise indicated in new editions. Last updated: 2020-09-08 © Copyright International Business Machines Corporation 1990, 2020. US Government Users Restricted Rights – Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. Contents Figures................................................................................................................. xi Tables................................................................................................................ xiii About This Document...........................................................................................xv Intended Audience..................................................................................................................................... xv Syntax, Message, and Response Conventions...........................................................................................xv Where to Find More Information.............................................................................................................xviii Links to Other Documents and Websites.......................................................................................... xviii How to Send Your Comments to IBM....................................................................xix Summary of Changes for z/VM REXX/VM Reference.............................................xxi SC24-6314-01, z/VM 7.2 (September 2020)...........................................................................................xxi SC24-6314-00, z/VM 7.1 (September 2018)...........................................................................................xxi SC24-6221-02, z/VM 6.4 (November 2016)............................................................................................xxi Chapter 1. REXX General Concepts........................................................................ 1 Structure and General Syntax......................................................................................................................1 Characters...............................................................................................................................................2 Comments...............................................................................................................................................2 Tokens.....................................................................................................................................................3 Implied Semicolons................................................................................................................................6 Continuations..........................................................................................................................................6 Expressions and Operators..........................................................................................................................7 Expressions.............................................................................................................................................7 Operators................................................................................................................................................7 Clauses and Instructions...........................................................................................................................12 Null Clauses..........................................................................................................................................12 Labels....................................................................................................................................................12 Instructions.......................................................................................................................................... 12 Assignments......................................................................................................................................... 13 Keyword Instructions...........................................................................................................................13 Commands............................................................................................................................................13 Assignments and Symbols........................................................................................................................ 13 Constant Symbols................................................................................................................................ 14 Simple Symbols....................................................................................................................................14 Compound Symbols............................................................................................................................. 14 Stems....................................................................................................................................................15 Commands to External Environments.......................................................................................................17 Environment......................................................................................................................................... 17 Commands............................................................................................................................................17 The CMS Environment..........................................................................................................................18 The COMMAND Environment............................................................................................................... 19 Issuing Subcommands from Your Program.........................................................................................20 Using the Online HELP Facility...................................................................................................................20 Chapter 2. Keyword Instructions......................................................................... 23 ADDRESS....................................................................................................................................................24 iii ARG.............................................................................................................................................................27 CALL............................................................................................................................................................29 DO...............................................................................................................................................................32 Simple DO Group....................................................................................................................................... 32 Repetitive DO Loops.................................................................................................................................. 33 Simple Repetitive Loops............................................................................................................................ 33 Controlled Repetitive Loops...................................................................................................................... 33 Conditional Phrases (WHILE and UNTIL)..................................................................................................34 DROP.......................................................................................................................................................... 36 EXIT............................................................................................................................................................37 IF................................................................................................................................................................ 38 INTERPRET................................................................................................................................................ 39 ITERATE..................................................................................................................................................... 41 LEAVE......................................................................................................................................................... 42 NOP............................................................................................................................................................ 43 NUMERIC....................................................................................................................................................44 OPTIONS.................................................................................................................................................... 46 PARSE.........................................................................................................................................................48 PROCEDURE...............................................................................................................................................51