clear: int argument;

--- a/src/Pure/Isar/proof_history.ML	Tue Oct 05 15:35:34 1999 +0200
+++ b/src/Pure/Isar/proof_history.ML	Tue Oct 05 15:35:48 1999 +0200
@@ -13,7 +13,7 @@
   val init: int option -> Proof.state -> T
   val is_initial: T -> bool
   val current: T -> Proof.state
-  val clear: T -> T
+  val clear: int -> T -> T
   val undo: T -> T
   val redo: T -> T
   val back: bool -> T -> T
@@ -48,7 +48,7 @@
 fun init lim st = ProofHistory (History.init lim ((st, Seq.empty), []));
 fun is_initial (ProofHistory prf) = History.is_initial prf;
 fun current (ProofHistory prf) = fst (fst (History.current prf));
-val clear = app History.clear;
+val clear = app o History.clear;
 val undo = app History.undo;
 val redo = app History.redo;