On Tue, Feb 18, 2020 at 1:21 PM Arthur A. Gleckler <xxxxxx@speechcode.com> wrote:
 I've found being able to add arbitrary operations to ports, depending on circumstances, to be highly useful.  Sometimes, they're so useful that they get promoted to standard operations, or wrapped in procedures so that they don't have to be looked up on the alist, but the general mechanism is highly useful.

I'd appreciate some examples.

John Cowan          http://vrici.lojban.org/~cowan        xxxxxx@ccil.org
Evolutionary psychology is the theory that men are nothing but horn-dogs,
and that women only want them for their money.  --Susan McCarthy (adapted)