ex/PL0.ML

Used Datatype functor to define propositional logic terms.

(*  Title: 	HOL/ex/pl0.ML
    ID:         $Id$
    Author: 	Tobias Nipkow
    Copyright   1994  TU Muenchen

Inductive definition of propositional logic formulae.
*)

structure PL0 = DeclaredDatatype
(val base = PL0.thy
 val data = "'a pl = false | var('a) | \"op->\"('a pl,'a pl)"
);