ex/PL0.thy

adopted to new datatype definition method

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

Syntax of propositional logic formulae.
*)

PL0 = HOL +
types 'a pl
arities pl :: (term)term
consts
    false	:: "'a pl"
    "->"	:: "['a pl,'a pl] => 'a pl"	(infixr 90)
    var		:: "'a => 'a pl"		("#_")
datatype
    'a pl = false | var('a) | "op->" ('a pl,'a pl)
end