doc-src/IsarAdvanced/Codegen/Thy/examples/class.ML
changeset 25056 743f3603ba8b
parent 24628 33137422d7fd
child 25182 64e3f45dc6f4
--- a/doc-src/IsarAdvanced/Codegen/Thy/examples/class.ML	Tue Oct 16 17:06:21 2007 +0200
+++ b/doc-src/IsarAdvanced/Codegen/Thy/examples/class.ML	Tue Oct 16 17:07:40 2007 +0200
@@ -14,9 +14,11 @@
 fun head B_ (x :: xs) = x
   | head B_ [] = null B_;
 
-fun null_option () = {null = NONE} : ('a option) null;
+val null_option : 'a option = NONE;
+
+fun null_optiona () = {null = null_option} : ('a option) null;
 
 val dummy : Nat.nat option =
-  head (null_option ()) [SOME (Nat.Suc Nat.Zero_nat), NONE];
+  head (null_optiona ()) [SOME (Nat.Suc Nat.Zero_nat), NONE];
 
 end; (*struct Codegen*)