macro invocation to CALL routines

In macro world, we have to use %sysfunc to call SAS functions.
Accordingly, %syscall is the door to SAS CALL routines.

%let pattern = %sysfunc(prxparse(/test/i));
%let rc = %sysfunc(prxmatch(&pattern, %str(this is a test)));
%syscall prxfree(pattern);