This is an inbuilt function function provided by PPWIZARD.
This routine simplifies the addition of data into arrays and makes the code easier to understand.
Each time this routine is called the supplied data is added onto the end of the array (stem).
If the array did not exist it is created then updated.
The function takes 1 or 2 parameters as follows:
The routine returns the number of items in the array. As per normal rexx convention, this value is also saved into the ".0" item.