diff -r 07dad1433cd7 -r 2fa51ac191bc src/Pure/PIDE/isar_document.scala
--- a/src/Pure/PIDE/isar_document.scala	Sat Sep 03 12:31:27 2011 +0200
+++ b/src/Pure/PIDE/isar_document.scala	Sat Sep 03 18:08:09 2011 +0200
@@ -188,6 +188,14 @@
     input("Isar_Document.update", Document.ID(old_id), Document.ID(new_id), edits_yxml)
   }
 
+  def remove_versions(versions: List[Document.Version])
+  {
+    val versions_yxml =
+      { import XML.Encode._
+        YXML.string_of_body(list(long)(versions.map(_.id))) }
+    input("Isar_Document.remove_versions", versions_yxml)
+  }
+
 
   /* method invocation service */