[net.lang.prolog] Defining var

bhyde@inmet.UUCP (06/26/86)

The prolog that I use loads a library of standard
definitions upon start up.  I got to wondering 
what things are truly primative in prolog.  Somebody
asked recently if the predicate var can be defined
"logically."  How's this?
  var(X) :- not(not(X=1)), not(not(X=2).

Now can we define the operator "=="?  Notable is
that:
   : X == X?
   true.
   : X == Y?
   false.
At least in some implementations.

    - ben hyde, cambridge mass.