Procedure that runs the
template, filling its slots with the remaining input(s).
The number of inputs must be an acceptable number of slots for
It is illegal to use the primitive TO as a template, but anything else is okay.
INVOKE outputs what
template outputs, if anything.
INVOKE is similar to APPLY except that INVOKE's inputs are provided as separate expressions rather than in a list.
SHOW (INVOKE "SUM 1 2 3)6