(*  Title: 	FOL/ex/prolog.thy

     ID:         $Id$

     Author: 	Lawrence C Paulson, Cambridge University Computer Laboratory

     Copyright   1992  University of Cambridge

 First-Order Logic: PROLOG examples

 Inherits from FOL the class term, the type o, and the coercion Trueprop

 *)

 Prolog = FOL +

 types   'a list

 arities list    :: (term)term

 consts  Nil     :: "'a list"

         ":"     :: "['a, 'a list]=> 'a list"            (infixr 60)

         app     :: "['a list, 'a list, 'a list] => o"

         rev     :: "['a list, 'a list] => o"

 rules   appNil  "app(Nil,ys,ys)"

         appCons "app(xs,ys,zs) ==> app(x:xs, ys, x:zs)"

         revNil  "rev(Nil,Nil)"

         revCons "[| rev(xs,ys);  app(ys, x:Nil, zs) |] ==> rev(x:xs, zs)"

 end