doc-src/TutorialI/Trie/Option2.thy
author wenzelm
Sun, 25 Jun 2000 23:46:39 +0200
changeset 9122 addbea344673
parent 8771 026f37a86ea7
permissions -rw-r--r--
added state: 'a * 'b -> 'a * ('a * 'b);

(*<*)
theory Option2 = Main:;
(*>*)

datatype 'a option = None | Some 'a;
(*<*)
end
(*>*)