Issue CONSTANT-MODIFICATION, version 2

[Jon L White <jonl@lucid.com>]

re: But why can't constants be modified in compiled code?  It seems clear
    that they could be, so there must be some reasons why they aren't
    always modifiable, and those are the real reasons.

There's the implementational reason, as verified by the "current practice"
of several widespread implementations (I see Sandra invoked this reason
in her reply).  There's also a semantic consistency reason -- "constants"
should be constant, and not simply global parameters subject to casual 
alteration during the running of the program.  Remember the "Indiana rule"
       (setn pi 3.0)


-- JonL --


P.S., No typo! -- Interlisp has the SETN operator even though CL doesn't