I guess I never noticed that the existing ++ operator could take a second argument, sorry.
However, the *= and /= operators are still very useful, and it would be very cool if a simple ssyntax could make it general to all single argument functions, or at least functions in which the first argument is the one being modified/extended. Good examples would be += as applies to alists and tables, and things like cut or sort.
Is there a reason that you can't append an atom to a list with '+ or '++?
