src/HOL/Option.thy
changeset 2019 b45d9f2042e0
child 4133 0a08c2b9b1ed
     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/HOL/Option.thy	Tue Sep 24 09:02:34 1996 +0200
     1.3 @@ -0,0 +1,11 @@
     1.4 +(*  Title:      Option.thy
     1.5 +    ID:         $Id$
     1.6 +    Author:     Tobias Nipkow
     1.7 +    Copyright   1994  TU Muenchen
     1.8 +
     1.9 +Datatype 'a option
    1.10 +*)
    1.11 +
    1.12 +Option = Arith +
    1.13 +datatype 'a option = None | Some 'a
    1.14 +end