Re: COPYTREE

[DLW at MIT-AI (Daniel L. Weinreb)]

After some discussion, I have come to the opinion that whether or not
we put in various hairy general-purpose customizable extensible
copying functions, it is clearly useful have a simple function to
do what (subst nil nil ...) does.  People use (subst nil nil ...)
a lot; there should be a SIMPLE, EASY thing to replace this nasty
idiomatic in-joke.  There should be a function that you can just call,
and get the commonly-wanted thing to happen.  I continue to push for
installation of COPYTREE.

(Something that copies uninterned symbols and bignums is presumably
useful mostly for people who understand a little about storage
management and are hacking areas or something; this is clearly the
sort of thing that you'd only expect experts to be using, and it
deserves keywords, features, and a longer name.)