Introducing REXX
Introduces you to the REXX programming language and its features.
| REXX execs
Features and components of REXX. Recognizing a REXX exec. Basic syntax rules. |
| Variables, Expressions and Operators
Assigning names and values to variables. Using REXX to perform arithmetic calculations. Precedence of arithmetic operators used in REXX. |
| More Operators
Using the comparative, logical and concatenation operators. |
Basic REXX Instructions
Presents basic REXX instructions. Explains how to store data on the stack.
| Writing to the Terminal
Writing to the terminal with a SAY instruction. |
| Reading from the Terminal
Reading from the terminal with the PULL instruction. Retrieving data from the command line using the ARG instruction. |
| Selection Techniques
Controlling the logic flow within REXX by using IF/THEN/ELSE instructions. Using the NOP instruction. How to unconditionally leave a REXX exec with the EXIT instruction. |
| Simple DO Loops
Using simple DO loops. Adding the LEAVE instruction to terminate a DO FOREVER group. |
| Stack
Definition of a stack. Manipulation of the stack using PULL, PUSH and QUEUE. |
Program Control
Explores more complex selection techniques and DO structures. Discusses subroutines and the interrupt instruction SIGNAL.
| Advanced Selection Techniques
Using SELECT/WHEN/OTHERWISE in a REXX exec. |
| Complex DO Structures
How to manage controlled repetitive loops. How to nest loops. Use of the ITERATE instruction. |
| Subroutines
Coding simple subroutines in a REXX exec. Passing data between a calling exec and subroutine. Using the PROCEDURE instruction with or without the EXPOSE option. |
| Control Jumps
Using the SIGNAL instruction to alter the flow of program control. |
REXX Functions
Covers the three categories of REXX functions.
| Comparison/Formatting
Calling a function in a REXX exec. Employing comparison functions: COMPARE and DATATYPE. Using formatting functions: CENTER, LEFT, RIGHT, COPIES and SPACE. |
| String Manipulating
Using string manipulating functions: STRIP, SUBSTR, SUBWORD, OVERLAY, LENGTH, WORDS, WORDLENGTH, WORD, WORDINDEX, WORDPOS and POS.
Advanced Program Features
Describes advanced features in REXX programming. |
| Compound Variables and Arrays
Using compound variables to set up arrays and lists of variables. Using the stem to change a collection of variables. |
| The PARSE Instruction
Using PARSE PULL, PARSE VAR and PARSE VALUE in a REXX exec. |
| Using the Stack
Adding and dropping buffers from the stack. How PUSH, PULL and QUEUE act on the buffers. Using QUEUE() to return the number of entries in the stack. |
| Debugging
Using the TRACE instruction to debug a REXX exec. Names of TRACE options. |
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