src/Pure/PIDE/session.scala

     previous: Document.Version,
     syntax_changed: List[Document.Node.Name],
     deps_changed: Boolean,
     doc_edits: List[Document.Edit_Command],
     consolidate: List[Document.Node.Name],
+    share_common_data: Boolean,
     version: Document.Version)
 
   case object Change_Flush
 
 

 
   //{{{
   case class Statistics(props: Properties.T)
   case class Global_Options(options: Options)
   case object Caret_Focus
-  case class Raw_Edits(doc_blobs: Document.Blobs, edits: List[Document.Edit_Text])
+  case class Raw_Edits(
+    doc_blobs: Document.Blobs, edits: List[Document.Edit_Text], share_common_data: Boolean)
   case class Dialog_Result(id: Document_ID.Generic, serial: Long, result: String)
   case class Build_Theories(id: String, master_dir: Path, theories: List[(Options, List[Path])])
   case class Commands_Changed(
     assignment: Boolean, nodes: Set[Document.Node.Name], commands: Set[Command])
 

   private case class Text_Edits(
     previous: Future[Document.Version],
     doc_blobs: Document.Blobs,
     text_edits: List[Document.Edit_Text],
     consolidate: List[Document.Node.Name],
+    share_common_data: Boolean,
     version_result: Promise[Document.Version])
 
   private val change_parser = Consumer_Thread.fork[Text_Edits]("change_parser", daemon = true)
   {
-    case Text_Edits(previous, doc_blobs, text_edits, consolidate, version_result) =>
+    case Text_Edits(previous, doc_blobs, text_edits, consolidate, share_common_data, version_result) =>
       val prev = previous.get_finished
       val change =
         Timing.timeit("parse_change", timing) {
-          resources.parse_change(reparse_limit, prev, doc_blobs, text_edits, consolidate)
+          resources.parse_change(
+            reparse_limit, prev, doc_blobs, text_edits, consolidate, share_common_data)
         }
       version_result.fulfill(change.version)
       manager.send(change)
       true
   }

     /* raw edits */
 
     def handle_raw_edits(
       doc_blobs: Document.Blobs = Document.Blobs.empty,
       edits: List[Document.Edit_Text] = Nil,
-      consolidate: List[Document.Node.Name] = Nil)
+      consolidate: List[Document.Node.Name] = Nil,
+      share_common_data: Boolean = false)
     //{{{
     {
       require(prover.defined)
 
       prover.get.discontinue_execution()
 
       val previous = global_state.value.history.tip.version
       val version = Future.promise[Document.Version]
       global_state.change(_.continue_history(previous, edits, version))
 
-      raw_edits.post(Session.Raw_Edits(doc_blobs, edits))
-      change_parser.send(Text_Edits(previous, doc_blobs, edits, consolidate, version))
+      raw_edits.post(Session.Raw_Edits(doc_blobs, edits, share_common_data))
+      change_parser.send(
+        Text_Edits(previous, doc_blobs, edits, consolidate, share_common_data, version))
     }
     //}}}
 
 
     /* resulting changes */

         edit.foreach({ case (c1, c2) => c1.foreach(id_command); c2.foreach(id_command) })
       }
 
       val assignment = global_state.value.the_assignment(change.previous).check_finished
       global_state.change(_.define_version(change.version, assignment))
+
+      if (change.share_common_data) {
+        prover.get.protocol_command("ML_Heap.share_common_data")
+      }
       prover.get.update(change.previous.id, change.version.id, change.doc_edits, change.consolidate)
       resources.commit(change)
     }
     //}}}
 

             global_options.post(Session.Global_Options(options))
 
           case Cancel_Exec(exec_id) if prover.defined =>
             prover.get.cancel_exec(exec_id)
 
-          case Session.Raw_Edits(doc_blobs, edits) if prover.defined =>
-            handle_raw_edits(doc_blobs = doc_blobs, edits = edits)
+          case Session.Raw_Edits(doc_blobs, edits, share_common_data) if prover.defined =>
+            handle_raw_edits(doc_blobs = doc_blobs, edits = edits,
+              share_common_data = share_common_data)
 
           case Session.Dialog_Result(id, serial, result) if prover.defined =>
             prover.get.dialog_result(serial, result)
             handle_output(new Prover.Output(Protocol.Dialog_Result(id, serial, result)))
 

   { manager.send(Protocol_Command(name, args.toList)) }
 
   def cancel_exec(exec_id: Document_ID.Exec)
   { manager.send(Cancel_Exec(exec_id)) }
 
-  def update(doc_blobs: Document.Blobs, edits: List[Document.Edit_Text])
-  { if (edits.nonEmpty) manager.send_wait(Session.Raw_Edits(doc_blobs, edits)) }
+  def update(
+    doc_blobs: Document.Blobs,
+    edits: List[Document.Edit_Text],
+    share_common_data: Boolean = false)
+  {
+    if (edits.nonEmpty) manager.send_wait(Session.Raw_Edits(doc_blobs, edits, share_common_data))
+  }
 
   def update_options(options: Options)
   { manager.send_wait(Update_Options(options)) }
 
   def dialog_result(id: Document_ID.Generic, serial: Long, result: String)