(EQV? '(A) '(A))

[Jonathan A Rees <JAR@MC.LCS.MIT.EDU>]

    Date: 26 Mar 1986  17:11 EST (Wed)
    From: Bill Rozas <JINX%OZ.AI.MIT.EDU at XX.LCS.MIT.EDU>

        2. Should we require (EQV? '(A) '(A)) to return true in implementations
        which forbid clobbering quoted structure (that would be all
        implementations, if the answer to 1. is yes)?  

    Although it would be nice, it seems that it has serious implementation
    consequences: either quoted structure is hash-consed (BTW, what happens
    them to immutable parts of back-quoted structure?), or EQV? becomes
    more expensive than it already is.

Why should non-constant-time behavior be desirable for numbers, but
desirable for lists?  Immutable structured data with identical
components are "operationally identical", and I'm endeavoring to make
EQV? a close approximation to the operationally-identitical relation.

The backquoted structure question is a sticky one.  Don't know quite
what to do about it.