In a triangle, we use terms like adjacent and opposite. These refer to sides in relation to angles. In our musical triangle, the drummer is at one angle in the back. This side, where the audience is, is called the opposite side.
Trunc is database function, try using round for numeric values, or change the Processing of Query to database.
The introduction of %sysfunc function enabled the macro processor to access most data step functions and several SAS Component Language (SCL) functions allowing for nvars to easily be extracted using a SAS Macro Function. Therefore, the ability to avoid the implementation issues that arose before is now a reality.