hash table question

["Scott E. Fahlman" <Fahlman@C.CS.CMU.EDU>]

The hashing obviously will be messed up if you make destructive changes
that would alter the key under which things are hashed.  If you have
things stored in an EQ hash table and you change the datum in such a way
that the resulting objects are still EQ, things should still work.
Ditto if you have a EQUAL hash-table and change an entry in some way
that leaves it EQUAL to what it was before.  But if you sneak in and
change some list element from 3 to 'foo, the datum would no longer be
hashed properly and you can only win if you remove the datum and then
re-enter it into the hash-table.

-- Scott