the value of this CDEF at the previous time step. This allows you to
perform calculations across the data.
+=item COUNT
+
+Pushes the number 1 if it is at the first value of the data set, the
+number 2 if it is at the second, and so on. This special value, allows
+you to make calculations based on the position of the value within
+the data set.
+
=item INF, NEGINF
Push a positive or negative infinite (oo) value onto the stack. When