tuned signature;

--- a/src/Pure/PIDE/batch_session.scala	Mon Mar 13 22:02:42 2017 +0100
+++ b/src/Pure/PIDE/batch_session.scala	Mon Mar 13 22:50:26 2017 +0100
@@ -53,8 +53,7 @@
         case _ =>
       }
 
-    prover_session.start(receiver =>
-      Isabelle_Process(options, logic = parent_session, receiver = receiver))
+    Isabelle_Process.start(prover_session, options, logic = parent_session)
 
     batch_session
   }

--- a/src/Pure/System/isabelle_process.scala	Mon Mar 13 22:02:42 2017 +0100
+++ b/src/Pure/System/isabelle_process.scala	Mon Mar 13 22:50:26 2017 +0100
@@ -9,6 +9,19 @@
 
 object Isabelle_Process
 {
+  def start(session: Session,
+    options: Options,
+    logic: String = "",
+    args: List[String] = Nil,
+    dirs: List[Path] = Nil,
+    modes: List[String] = Nil,
+    store: Sessions.Store = Sessions.store())
+  {
+    session.start(receiver =>
+      Isabelle_Process(options, logic = logic, args = args, dirs = dirs, modes = modes,
+        receiver = receiver, store = store))
+  }
+
   def apply(
     options: Options,
     logic: String = "",

--- a/src/Tools/VSCode/src/server.scala	Mon Mar 13 22:02:42 2017 +0100
+++ b/src/Tools/VSCode/src/server.scala	Mon Mar 13 22:50:26 2017 +0100
@@ -251,9 +251,8 @@
 
       dynamic_output.init()
 
-      session.start(receiver =>
-        Isabelle_Process(options = options, logic = session_name, dirs = session_dirs,
-          modes = modes, receiver = receiver))
+      Isabelle_Process.start(session, options,
+        logic = session_name, dirs = session_dirs, modes = modes)
     }
   }
 

--- a/src/Tools/jEdit/src/jedit_sessions.scala	Mon Mar 13 22:02:42 2017 +0100
+++ b/src/Tools/jEdit/src/jedit_sessions.scala	Mon Mar 13 22:50:26 2017 +0100
@@ -65,10 +65,9 @@
       (space_explode(',', PIDE.options.string("jedit_print_mode")) :::
        space_explode(',', Isabelle_System.getenv("JEDIT_PRINT_MODE"))).reverse
 
-    PIDE.session.start(receiver =>
-      Isabelle_Process(options = session_options(), logic = session_name(), dirs = session_dirs(),
-        modes = modes, receiver = receiver,
-        store = Sessions.store(session_build_mode() == "system")))
+    Isabelle_Process.start(PIDE.session, session_options(),
+      logic = session_name(), dirs = session_dirs(), modes = modes,
+      store = Sessions.store(session_build_mode() == "system"))
   }
 
   def session_list(): List[String] =