Major Section: THEORIES
Example:
(set-difference-theories (current-theory :here)
'(fact (fact)))
General Form:
(set-difference-theories th1 th2)
where th1 and th2 are theories (see theories). To each of
the arguments there corresponds a runic theory. This function
returns the set-difference of those two runic theories, represented
as a list and ordered chronologically. That is, a rune is in the
result iff it is in the first runic theory but not in the second.
The standard way to ``disable'' a theory, lst, is:
(in-theory (set-difference-theories (current-theory :here) lst)).
This ``function'' is actually a macro that expands to a term
mentioning the single free variable world. When theory expressions
are evaluated by in-theory or the :in-theory hint, world is bound to
the current ACL2 world.