REXX Coding Considerations

REXX handles the asterisk (*) both as a wildcard character and as the multiplication character:

Many of the host commands use an asterisk (*) to indicate an omitted parameter. If you do not place the asterisk in quotes, REXX will assume that the asterisk is the multiplication operator.
If you enter:
```
RDSCRROW  *  5
```
REXX will try to multiply the variable RDSCRROW times 5. Depending on the value of RDSCRROW, REXX can fail. In the worst case, the value of RDSCRROW would be an integer, which would cause an incorrect result.

If you enter:
```
RDSCRROW  '*'  5
```
REXX understands that the asterisk is used as a substitute character. When the command executes, REXX transforms the statement to:
```
RDSCRROW * 5
```
The REXX abuttal operator (||) accomplishes string abuttal concatenation. In the examples, the abuttal operator is only used when absolutely necessary, usually between two REXX variables. If string concatenation is performed using one or more blanks, only one blank will be passed to the EPI.
The fact that REXX removes enclosing quotes should not be a problem. A means is provided for supplying single and double quotes in the TYPE and TYPETEST host commands. If you want to pass a single or double quote to the EPI in a host command, be sure to enclose it in another set of quotes. Only the outer quotes will be removed by REXX before passing it to the EPI.