Understanding REXX Statement Processing

REXX processes statements as follows:

REXX treats every word in a statement as a REXX variable. The default value for each variable is the variable name itself.
REXX calls its own built-in functions if a statement requires them, and places the values returned from the functions into variables.
REXX processes each statement arithmetically, removing operators such as *, /, +, and commas.
If REXX does not recognize the resulting statement, it passes the statement to the current environment as a host command.
REXX recognizes variables that the AXC ADDRESS environment must resolve when the variables appear within a string surrounded by quotation marks.
Specify variables for the AXC ADDRESS environment to resolve by prefixing them with an ampersand character (&). For example, the following statement places the value of the REXX variable MSG_CONTENTS into the CA Automation Point variable &MSG_TEXT:
```
"SETVAR MSG_TEXT (&MSG_CONTENTS)"
```
When specifying REXX variables as part of a statement, you can also use double quotation marks to offset the variables. For example, to substitute 'THIS IS A MESSAGE FROM REXX' for MSG_CONTENTS, use this syntax:
```
MSG_CONTENTS = 'THIS IS A MESSAGE FROM REXX'
"SETVAR REXX_MESSAGE ("MSG_CONTENTS ")"
```
When REXX encounters this statement, it substitutes only MSG_CONTENTS and preserves the parentheses.