Re: Highlighting rectangles?

[Richard Stallman]

    My marking system signal error if the 1st mark type != 2nd mark type.
    It check the mark type and give an error message if the type does not
    match the operation.

I see.  I guess that prevents certain kinds of confusion.

What happens with the many Emacs commands that operate on the
(linear) region?  If you mark a rectangle with your package
and then use (say) fill-region, what happens?