DISPLACE

[Alan Bawden <ALAN at MIT-MC>]

You have got to be kidding.

Do you really use DISPLACE in situations where you could just as well
say RPLACA and RPLACD?  What possible reason could there be for adding
a DISPLACE to maclisp that had this simple definition?  As I
understand it, the reason DISPLACE was added in the first place was to
factor out of all the displacing macros in the world the common final
step they ALL HAD to do.  I thought the definition of DISPLACE was
sufficiently bizarre that no one could ever make the mistake of
considering it for use other than in a displacing macro.

I would argue that you have been misusing DISPLACE, and we should be
allowed to make this change even if it breaks some of your code.