misc tuning and simplification;

--- a/src/Pure/ProofGeneral/proof_general_pgip.ML	Tue May 14 15:40:18 2013 +0200
+++ b/src/Pure/ProofGeneral/proof_general_pgip.ML	Tue May 14 16:04:26 2013 +0200
@@ -1,8 +1,7 @@
 (*  Title:      Pure/ProofGeneral/proof_general_pgip.ML
     Author:     David Aspinall and Markus Wenzel
 
-Isabelle configuration for Proof General using PGIP protocol.
-See http://proofgeneral.inf.ed.ac.uk/kit
+Rudiments of PGIP for ProofGeneral preferences.
 *)
 
 signature PROOF_GENERAL_PGIP =
@@ -13,37 +12,24 @@
 structure ProofGeneralPgip : PROOF_GENERAL_PGIP =
 struct
 
-(* assembling and issuing PGIP packets *)
-
-val pgip_refid = Unsynchronized.ref NONE: string option Unsynchronized.ref;
-val pgip_refseq = Unsynchronized.ref NONE: int option Unsynchronized.ref;
+(* output PGIP packets *)
 
-local
-  val pgip_class  = "pg"
-  val pgip_tag = "Isabelle/Isar"
-  val pgip_id = "dummy"
-  val pgip_seq = Unsynchronized.ref 0
-  fun pgip_serial () = Unsynchronized.inc pgip_seq
+val pgip_id = "dummy";
+val pgip_serial = Synchronized.counter ();
 
-  fun assemble_pgip content =
-    XML.Elem(("pgip",
-             [("tag", pgip_tag), ("id", pgip_id)] @
-             PgipTypes.opt_attr "destid" (! pgip_refid) @
-             [("class", pgip_class)] @
-             PgipTypes.opt_attr "refid" (! pgip_refid) @
-             PgipTypes.opt_attr_map string_of_int "refseq" (! pgip_refseq) @
-             [("seq", string_of_int (pgip_serial ()))]),
-             content)
-in
-
-fun matching_pgip_id id = (id = pgip_id)
-
-fun output_pgip content = Output.urgent_message (XML.string_of (assemble_pgip content));
-
-end;
+fun output_pgip refid refseq content =
+  XML.Elem (("pgip",
+   [("tag", "Isabelle/Isar"), ("id", pgip_id)] @
+    PgipTypes.opt_attr "destid" refid @
+    [("class", "pg")] @
+    PgipTypes.opt_attr "refid" refid @
+    [("refseq", refseq)] @
+    [("seq", string_of_int (pgip_serial ()))]), content)
+  |> XML.string_of
+  |> Output.urgent_message;
 
 
-(* Preferences: tweak for PGIP interfaces *)
+(* preferences *)
 
 val preferences = Unsynchronized.ref Preferences.pure_preferences;
 
@@ -56,7 +42,7 @@
   | NONE => error ("Unknown prover preference: " ^ quote pref));
 
 
-(** PGIP/Emacs rudiments **)
+(* process_pgip *)
 
 local
 
@@ -66,10 +52,11 @@
   XML.Elem (("haspref", [("name", name), ("descr", descr), ("default", default)]),
     [PgipTypes.pgiptype_to_xml pgiptype]);
 
-fun process_element_emacs (XML.Elem (("askprefs", _), _)) =
+fun process_element refid refseq (XML.Elem (("askprefs", _), _)) =
       ! preferences |> List.app (fn (category, prefs) =>
-          output_pgip [XML.Elem (("hasprefs", [("prefcategory", category)]), map haspref prefs)])
-  | process_element_emacs (XML.Elem (("setpref", attrs), data)) =
+          output_pgip refid refseq
+            [XML.Elem (("hasprefs", [("prefcategory", category)]), map haspref prefs)])
+  | process_element _ _ (XML.Elem (("setpref", attrs), data)) =
       let
         val name =
           (case Properties.get attrs "name" of
@@ -77,39 +64,30 @@
           | NONE => invalid_pgip ());
         val value = XML.content_of data;
       in set_preference name value end
-  | process_element_emacs _ = invalid_pgip ();
+  | process_element _ _ _ = invalid_pgip ();
+
+fun process_pgip str =
+  (case XML.parse str of
+    XML.Elem (("pgip", attrs), pgips) =>
+      let
+        val class = PgipTypes.get_attr "class" attrs;
+        val dest = PgipTypes.get_attr_opt "destid" attrs;
+        val refid = PgipTypes.get_attr_opt "id" attrs;
+        val refseq = PgipTypes.get_attr "seq" attrs;
+        val processit =
+          (case dest of
+            NONE => class = "pa"
+          | SOME id => id = pgip_id);
+       in if processit then List.app (process_element refid refseq) pgips else () end
+  | _ => invalid_pgip ())
+  handle PgipTypes.PGIP msg => error (msg ^ "\n" ^ str);
 
 in
 
-fun process_pgip_emacs str =
-  let
-    val _ = pgip_refid := NONE;
-    val _ = pgip_refseq := NONE;
-  in
-    (case XML.parse str of
-      XML.Elem (("pgip", attrs), pgips) =>
-        let
-          val class = PgipTypes.get_attr "class" attrs;
-          val dest = PgipTypes.get_attr_opt "destid" attrs;
-          val seq = PgipTypes.read_pgipnat (PgipTypes.get_attr "seq" attrs);
-          val processit =
-            (case dest of
-              NONE => class = "pa"
-            | SOME id => matching_pgip_id id);
-         in
-           if processit then
-            (pgip_refid := PgipTypes.get_attr_opt "id" attrs;
-             pgip_refseq := SOME seq;
-             List.app process_element_emacs pgips)
-           else ()
-         end
-    | _ => invalid_pgip ())
-  end handle PgipTypes.PGIP msg => error (msg ^ "\n" ^ str);
-
 val _ =
   Outer_Syntax.improper_command
     (("ProofGeneral.process_pgip", Keyword.control), Position.none) "(internal)"
-    (Parse.text >> (fn str => Toplevel.imperative (fn () => process_pgip_emacs str)));
+    (Parse.text >> (fn str => Toplevel.imperative (fn () => process_pgip str)));
 
 end;