src/Pure/PIDE/isar_document.scala

       YXML.string_of_body(encode(edits)) }
 
     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 */
 
   def invoke_scala(id: String, tag: Invoke_Scala.Tag.Value, res: String)
   {