For each datatype `t' there is now a theorem `split_t_case' of the form
P(t_case f1 ... fn x) = ((!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1))&
...
(!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn)))
The simplifier now reduces !x. (..x.. & x = t & ..x..) --> P x
to (..t.. & ..t..) --> P t
(and similarly for t=x).
(* Title: Option.ML
ID: $Id$
Author: Tobias Nipkow
Copyright 1996 TU Muenchen
Derived rules
*)
val expand_option_case = split_option_case;