explicit checks stable_finished_theory/stable_command allow parallel asynchronous command transactions;
tuned;

--- a/src/Pure/PIDE/command.ML	Fri Apr 06 23:34:38 2012 +0200
+++ b/src/Pure/PIDE/command.ML	Sat Apr 07 16:41:59 2012 +0200
@@ -12,7 +12,6 @@
   val memo_value: 'a -> 'a memo
   val memo_eval: 'a memo -> 'a
   val memo_result: 'a memo -> 'a
-  val memo_stable: 'a memo -> bool
   val run_command: Toplevel.transition -> Toplevel.state -> Toplevel.state * unit lazy
 end;
 
@@ -58,11 +57,6 @@
     Result res => Exn.release res
   | _ => raise Fail "Unfinished memo result");
 
-fun memo_stable (Memo v) =
-  (case Synchronized.value v of
-    Result (Exn.Exn exn) => not (Exn.is_interrupt exn)
-  | _ => true);
-
 end;
 
 

--- a/src/Pure/PIDE/document.ML	Fri Apr 06 23:34:38 2012 +0200
+++ b/src/Pure/PIDE/document.ML	Sat Apr 07 16:41:59 2012 +0200
@@ -235,7 +235,7 @@
 
 
 
-(** document state -- content structure and execution process **)
+(** main state -- document structure and execution process **)
 
 abstype state = State of
  {versions: version Inttab.table,  (*version_id -> document content*)
@@ -298,13 +298,19 @@
 
 
 
-(** execute **)
+(** edit operations **)
+
+(* execute *)
+
+local
 
 fun finished_theory node =
   (case Exn.capture Command.memo_result (get_result node) of
     Exn.Res (st, _) => can (Toplevel.end_theory Position.none) st
   | _ => false);
 
+in
+
 fun execute version_id state =
   state |> map_state (fn (versions, commands, _) =>
     let
@@ -339,15 +345,27 @@
 
     in (versions, commands, (version_id, group, running)) end);
 
-
+end;
 
 
-(** edits **)
-
 (* update *)
 
 local
 
+fun stable_finished_theory node =
+  is_some (Exn.get_res (Exn.capture (fn () =>
+    fst (Command.memo_result (get_result node))
+    |> Toplevel.end_theory Position.none
+    |> Global_Theory.join_proofs) ()));
+
+fun stable_command exec =
+  (case Exn.capture Command.memo_result exec of
+    Exn.Exn exn => not (Exn.is_interrupt exn)
+  | Exn.Res (st, _) =>
+      (case try Toplevel.theory_of st of
+        NONE => true
+      | SOME thy => is_some (Exn.get_res (Exn.capture Global_Theory.join_recent_proofs thy))));
+
 fun make_required nodes =
   let
     val all_visible =
@@ -400,7 +418,7 @@
           (case opt_exec of
             NONE => true
           | SOME (exec_id, exec) =>
-              not (Command.memo_stable exec) orelse
+              not (stable_command exec) orelse
               (case lookup_entry node0 id of
                 NONE => true
               | SOME (exec_id0, _) => exec_id <> exec_id0));
@@ -453,7 +471,7 @@
     val updated =
       nodes |> Graph.schedule
         (fn deps => fn (name, node) =>
-          if is_touched node orelse is_required name andalso not (finished_theory node) then
+          if is_touched node orelse is_required name andalso not (stable_finished_theory node) then
             let
               val node0 = node_of old_version name;
               fun init () = init_theory deps node;