Writing REXX procedures course outline

Writing REXX procedures

Duration: 2 or 3 days

Audience: Experienced programmers and operations support staff who need to read and/or modify REXX procedures

Prequisites: Good working knowledge of a programming language

The Edit Macros and Library Management sections are optional and extend the course to 3 days

Objectives: Top Contents

On successful completion of this course each student will be able to:

* identify datasets which are currently allocated to a TSO user
* free and allocate datasets
* identify a dataset which will contain procedures/EXECs
* create and test a REXX procedure
* create procedures which accept parameters
* code conditional commands
* assign values to symbolic variables
* use stem variables
* use built-in functions
* use TSO/E functions
* communicate with the terminal
* communicate with system services
* use the TSO data stack
* access files from a REXX procedure
* use address to access other environments
* issue TSO commands
* use instructions which control the flow of execution
* use REXX to parse lines of data
* control and execute a program
* execute a REXX procedure in batch
* debug REXX procedures

Contents: Top Objectives

Introduction to REXX
Concepts, facilities, syntax; how an EXEC/procedure is interpreted, REXX compilation; variable names, assigning values; comparisons, arithmetic and boolean expressions; stem variables; built-in functions, translation; SYSVAR function; conversing with screen: SAY, PULL; external environments, ADDRESS, TSO, MVS, ISPEXEC, ISREDIT, LU62, LINKMVS, etc., SUBCOM; testing options, TRACE, EXECUTIL; accessing DB2, DSNREXX.

Sequence control
DO loops, conditional loops, DO FOREVER, LEAVE, ITERATE, IF .. THEN .. ELSE, SELECT, NOP, EXIT, SIGNAL, subroutines, CALL, passing parameters, ARG, RETURN.

Further REXX facilities
File handling, EXECIO with stack or stem variables; using the program stack, PUSH, PULL, QUEUE, PARSE EXTERNAL; using buffers on the stack; creating and manipulating extra stacks; useful TSO commands: allocate, free, LISTDSI; MVSVAR; capturing TSO output using OUTTRAP; PARSE, place holders, text handling; executing in batch (both non-TSO and IKJEFT01).

Edit macros
ISREDIT environment, invoking a macro, passing parameters to a macro from the terminal, passing data between macros and EXECs; assigning macro values to REXX variables; edit commands; accessing system information: DATASET, MEMBER, etc.; editing all members of a library.

Library Management
Processing a library: LMINIT, LMOPEN, LMCLOSE, LMFREE; processing members of a library: LMMLIST etc.; processing a dataset list: LMDINIT, LMDLIST, LMDDISP, LMDFREE, saving the list to a file.