X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fmatita%2FmatitaScript.ml;h=bd526212e45f9d7f88988f2ccb88341512dd9d5b;hb=624907fead9047f23557374788c5767b6289dd7c;hp=acb73fb54909f90da93c260e12b201798c9b15d2;hpb=642e20a0135126586603ffb539f0d1c1428f1502;p=helm.git

diff --git a/helm/matita/matitaScript.ml b/helm/matita/matitaScript.ml
index acb73fb54..bd526212e 100644
--- a/helm/matita/matitaScript.ml
+++ b/helm/matita/matitaScript.ml
@@ -1,4 +1,4 @@
-(* Copyright (C) 2005, HELM Team.
+(* Copyright (C) 2004-2005, HELM Team.
  * 
  * This file is part of HELM, an Hypertextual, Electronic
  * Library of Mathematics, developed at the Computer Science
@@ -24,189 +24,484 @@
  *)
 
 open Printf
-
 open MatitaTypes
 
-exception Script_failure of string
-
-let remove_constant_from_world ~dbd ~uri =
-  CicEnvironment.remove_obj uri;
-  MetadataDb.unindex ~dbd ~uri;
-  let uri = UriManager.string_of_uri uri in
-  List.iter
-    (* TODO ZACK remove xml files from disk *)
-    (fun suffix -> Http_getter.unregister (uri ^ suffix))
-    [""; ".body"; ".types"]
-
-let remove_inductive_def_from_world ~dbd ~uri =
-  remove_constant_from_world ~dbd ~uri;
-  let uri = UriManager.string_of_uri uri in
-  Http_getter.unregister uri;
-  List.iter
-    (fun suffix ->
-      let uri =
-        Pcre.replace ~pat:"\\.ind$" ~templ:(sprintf "_%s.con" suffix) uri
-      in
-      remove_constant_from_world ~dbd ~uri:(UriManager.uri_of_string uri))
-    ["ind"; "rec"; "rect"]
-
-let is_empty =
-  let rex = Pcre.regexp "^\\s*$" in
-  fun s ->
-    Pcre.pmatch ~rex s
-
-class script ~(interpreter:MatitaTypes.interpreter) () =
-  let gui = MatitaGui.instance () in
-  let script = gui#script in
-  let buf = script#scriptTextView#buffer in
-  let dbd = MatitaMisc.dbd_instance () in
-  let rec undo_item = function
-    | None -> ()
-    | Some item ->
-        (match item with
-        | `Tactic ->
-            let res =
-              interpreter#evalAst (TacticAst.Command (TacticAst.Undo None))
-            in
-            assert (fst res)
-        | `Theorem ->
-            interpreter#setState `Command;
-            (MatitaMathView.sequents_viewer_instance ())#reset
-        | `Qed uri
-        | `Def uri -> remove_constant_from_world ~dbd ~uri
-        | `Inductive uri -> remove_inductive_def_from_world ~dbd ~uri)
-  in
-  object (self)
-    initializer
-      let console = (MatitaGui.instance ())#console in
-      let w f () = ignore (console#wrap_exn (fun () -> f ())) in
-      ignore (gui#script#scriptWinTopButton#connect#clicked (w self#top));
-      ignore (gui#script#scriptWinBottomButton#connect#clicked (w self#bottom));
-      ignore (gui#script#scriptWinForwardButton#connect#clicked
-        (w self#forward));
-      ignore (gui#script#scriptWinBackButton#connect#clicked (w self#back));
-      ignore (gui#script#scriptWinTopButton#connect#clicked (w self#top));
-      ignore (gui#script#scriptWinJumpButton#connect#clicked (w self#jump))
-
-    val mutable items = []
-
-    (** {3 text buffer locking} *)
-
-      (** text mark and tag representing locked part of a script *)
-    val locked_mark =
-      buf#create_mark ~name:"locked" ~left_gravity:true buf#start_iter
-    val locked_tag = buf#create_tag [`BACKGROUND "lightblue"; `EDITABLE false]
-
-      (** lock script text view from the beginning to the given offset (in UTF-8
-      * characters) *)
-    method private lockScript offset =
-      let mark = `MARK locked_mark in
-      buf#move_mark mark ~where:(buf#get_iter_at_char offset);
-      buf#remove_tag locked_tag ~start:buf#start_iter ~stop:buf#end_iter;
-      buf#apply_tag locked_tag ~start:buf#start_iter
-        ~stop:(buf#get_iter_at_mark mark)
-
-    method win = gui#script
-
-    method loadFrom fname =
-      buf#set_text (MatitaMisc.input_file fname);
-      gui#script#scriptWin#show ();
-      gui#main#showScriptMenuItem#set_active true
-
-    method advance tactical =
-      let text = "\n" ^ TacticAstPp.pp_tactical tactical in
-      buf#insert ~iter:(buf#get_iter_at_mark (`NAME "locked")) text;
-      let res = self#_forward () in
-      if not (fst res) then begin
-        let locked_iter = buf#get_iter_at_mark (`NAME "locked") in
-        buf#delete ~start:locked_iter
-          ~stop:(locked_iter#forward_chars (String.length text));
-      end;
-      res
+let debug = true
+let debug_print = if  debug then prerr_endline else ignore
+
+  (** raised when one of the script margins (top or bottom) is reached *)
+exception Margin
+
+let safe_substring s i j =
+  try String.sub s i j with Invalid_argument _ -> assert false
 
-    (** {3 script progress} *)
+let heading_nl_RE = Pcre.regexp "^\\s*\n\\s*"
+let only_dust_RE = Pcre.regexp "^(\\s|\n|%%[^\n]*\n)*$"
+let multiline_RE = Pcre.regexp "^\n[^\n]+$"
+let newline_RE = Pcre.regexp "\n"
+ 
+let comment str =
+  if Pcre.pmatch ~rex:multiline_RE str then
+    "\n(** " ^ (Pcre.replace ~rex:newline_RE str) ^ " **)"
+  else
+    "\n(**\n" ^ str ^ "\n**)"
+                     
+let first_line s =
+  let s = Pcre.replace ~rex:heading_nl_RE s in
+  try
+    let nl_pos = String.index s '\n' in
+    String.sub s 0 nl_pos
+  with Not_found -> s
 
-    method private jump () =
-      let locked_iter () = buf#get_iter_at_mark (`NAME "locked") in
-      let cursor_iter = buf#get_iter_at_mark (`NAME "insert") in
-      let rec forward_until_cursor () =
-        prerr_endline "forward_until_cursor";
-          (* go forward until locked > cursor (or forward fails) *)
-        let success =
+let prepend_text header base =
+  if Pcre.pmatch ~rex:heading_nl_RE base then
+    sprintf "\n%s%s" header base
+  else
+    sprintf "%s\n%s" header base
+
+  (** creates a statement AST for the Goal tactic, e.g. "goal 7" *)
+let goal_ast n =
+  let module A = TacticAst in
+  let loc = CicAst.dummy_floc in
+  A.Executable (loc, A.Tactical (loc, A.Tactic (loc, A.Goal (loc, n))))
+
+let eval_with_engine status user_goal parsed_text st =
+  let module TA = TacticAst in
+  let module TAPp = TacticAstPp in
+  let parsed_text_length = String.length parsed_text in
+  let loc, ex = 
+    match st with TA.Executable (loc,ex) -> loc, ex | _ -> assert false 
+  in
+  let goal_changed = ref false in
+  let status =
+    match status.proof_status with
+      | Incomplete_proof (_, goal) when goal <> user_goal ->
+          goal_changed := true;
+          MatitaEngine.eval_ast status (goal_ast user_goal)
+      | _ -> status
+  in
+  let new_status = MatitaEngine.eval_ast status st in
+  let new_aliases =
+    match ex with
+      | TA.Command (_, TA.Alias _) ->
+          DisambiguateTypes.Environment.empty
+      | _ -> MatitaSync.alias_diff ~from:status new_status
+  in
+  (* we remove the defined object since we consider them "automathic aliases" *)
+  let new_aliases = 
+    let module DTE = DisambiguateTypes.Environment in
+    let module UM = UriManager in
+    DTE.fold (
+      fun k ((v,_) as value) acc -> 
+        let b = 
           try
-            fst (self#_forward ~stop:cursor_iter ())
-          with
-          | Script_failure _ | CicTextualParser2.Parse_error _ -> false
+            let v = UM.strip_xpointer (UM.uri_of_string v) in
+            List.exists (fun (s,_) -> s = v) new_status.objects 
+          with UM.IllFormedUri _ -> false
         in
-        if success && (locked_iter ())#compare cursor_iter < 0 then
-          forward_until_cursor ()
+        if b then 
+          acc
+        else
+          DTE.add k value acc
+    ) new_aliases DTE.empty
+  in
+  let new_text =
+    if DisambiguateTypes.Environment.is_empty new_aliases then
+      parsed_text
+    else
+      prepend_text (CicTextualParser2.EnvironmentP3.to_string new_aliases)
+        parsed_text
+  in
+  let new_text =
+    if !goal_changed then
+      prepend_text
+        (TAPp.pp_tactic (TA.Goal (loc, user_goal))(* ^ "\n"*))
+        new_text
+    else
+      new_text
+  in
+    [ new_status, new_text ], parsed_text_length
+
+let disambiguate term status =
+  let module MD = MatitaDisambiguator in
+  let dbd = MatitaDb.instance () in
+  let metasenv = MatitaMisc.get_proof_metasenv status in
+  let context = MatitaMisc.get_proof_context status in
+  let aliases = MatitaMisc.get_proof_aliases status in
+  let interps = MD.disambiguate_term dbd context metasenv aliases term in
+  match interps with 
+  | [_,_,x,_] -> x
+  | _ -> assert false
+ 
+let eval_macro status (mathviewer:MatitaTypes.mathViewer) urichooser parsed_text
+  script mac
+=
+  let module TA = TacticAst in
+  let module TAPp = TacticAstPp in
+  let module MQ = MetadataQuery in
+  let module MDB = MatitaDb in
+  let module CTC = CicTypeChecker in
+  let module CU = CicUniv in
+  (* no idea why ocaml wants this *)
+  let advance ?statement () = script#advance ?statement () in
+  let parsed_text_length = String.length parsed_text in
+  let dbd = MatitaDb.instance () in
+  match mac with
+  (* WHELP's stuff *)
+  | TA.WMatch (loc, term) -> 
+      let term = disambiguate term status in
+      let l =  MQ.match_term ~dbd term in
+      let entry = `Whelp (TAPp.pp_macro_cic (TA.WMatch (loc, term)), l) in
+      mathviewer#show_uri_list ~reuse:true ~entry l;
+      [], parsed_text_length
+  | TA.WInstance (loc, term) ->
+      let term = disambiguate term status in
+      let l = MQ.instance ~dbd term in
+      let entry = `Whelp (TAPp.pp_macro_cic (TA.WInstance (loc, term)), l) in
+      mathviewer#show_uri_list ~reuse:true ~entry l;
+      [], parsed_text_length
+  | TA.WLocate (loc, s) -> 
+      let l = MQ.locate ~dbd s in
+      let entry = `Whelp (TAPp.pp_macro_cic (TA.WLocate (loc, s)), l) in
+      mathviewer#show_uri_list ~reuse:true ~entry l;
+      [], parsed_text_length
+  | TA.WElim (loc, term) ->
+      let term = disambiguate term status in
+      let uri =
+        match term with
+        | Cic.MutInd (uri,n,_) -> UriManager.uri_of_uriref uri n None 
+        | _ -> failwith "Not a MutInd"
       in
-      let rec back_until_cursor () = (* go backward until locked < cursor *)
-        prerr_endline "back_until_cursor";
-        let res = self#back () in
-        if (locked_iter ())#compare cursor_iter > 0 then
-          back_until_cursor ()
+      let l = MQ.elim ~dbd uri in
+      let entry = `Whelp (TAPp.pp_macro_cic (TA.WElim (loc, term)), l) in
+      mathviewer#show_uri_list ~reuse:true ~entry l;
+      [], parsed_text_length
+  | TA.WHint (loc, term) ->
+      let term = disambiguate term status in
+      let s = ((None,[0,[],term], Cic.Meta (0,[]) ,term),0) in
+      let l = List.map fst (MQ.experimental_hint ~dbd s) in
+      let entry = `Whelp (TAPp.pp_macro_cic (TA.WHint (loc, term)), l) in
+      mathviewer#show_uri_list ~reuse:true ~entry l;
+      [], parsed_text_length
+  (* REAL macro *)
+  | TA.Hint loc -> 
+      let s = MatitaMisc.get_proof_status status in
+      let l = List.map fst (MQ.experimental_hint ~dbd s) in
+      let selected = urichooser l in
+      (match selected with
+      | [] -> [], parsed_text_length
+      | [uri] -> 
+        let ast = 
+          (TA.Executable (loc,
+            (TA.Tactical (loc, 
+               TA.Tactic (loc,
+                 TA.Apply (loc, CicAst.Uri (UriManager.string_of_uri uri,None))))))) 
+        in
+        let new_status = MatitaEngine.eval_ast status ast in
+        let extra_text = 
+          comment parsed_text ^ 
+          "\n" ^ TAPp.pp_statement ast
+        in
+        [ new_status , extra_text ], parsed_text_length
+      | _ -> 
+          MatitaLog.error 
+            "The result of the urichooser should be only 1 uri, not:\n";
+          List.iter (
+            fun u -> MatitaLog.error (UriManager.string_of_uri u ^ "\n")
+          ) selected;
+          assert false)
+  | TA.Check (_,term) ->
+      let metasenv = MatitaMisc.get_proof_metasenv status in
+      let context = MatitaMisc.get_proof_context status in
+      let aliases = MatitaMisc.get_proof_aliases status in
+      let interps = 
+        MatitaDisambiguator.disambiguate_term 
+          dbd context metasenv aliases term 
       in
-      let cmp = (locked_iter ())#compare cursor_iter in
-      if cmp < 0 then       (* locked < cursor *)
-        (prerr_endline "locked < cursor"; forward_until_cursor ())
-      else if cmp > 0 then  (* locked > cursor *)
-        (prerr_endline "locked > cursor"; back_until_cursor ())
-      else                  (* cursor = locked *)
-        ()
-
-    method private top () =
-      try while true do self#back () done with Script_failure _ -> ()
-
-    method private bottom () =
-      try
-        while true do
-          let res = self#_forward () in
-          if not (fst res) then raise (Script_failure "error")
-        done
-      with Script_failure _ -> ()
-
-    method private _forward ?(stop = buf#end_iter) () =
-      let locked_iter = buf#get_iter_at_mark (`NAME "locked") in
-      let (success, hide) as res =
-        let text = buf#get_text ~start:locked_iter ~stop () in
-        if is_empty text then
-          raise (Script_failure "at bottom")
-        else
-          interpreter#evalPhrase text
+      let _, metasenv , term, ugraph =
+        match interps with 
+        | [x] -> x
+        | _ -> assert false
       in
-      if success then begin
-        let old_offset = locked_iter#offset in
-        let new_offset = old_offset + interpreter#endOffset in
-        self#lockScript new_offset;
-        items <- (interpreter#lastItem, old_offset) :: items
-      end;
-      res
+      let ty,_ = CTC.type_of_aux' metasenv context term ugraph in
+      let t_and_ty = Cic.Cast (term,ty) in
+      mathviewer#show_entry (`Cic (t_and_ty,metasenv));
+      [], parsed_text_length
+(*   | TA.Abort _ -> 
+      let rec go_back () =
+        let status = script#status.proof_status in
+        match status with
+        | No_proof -> ()
+        | _ -> script#retract ();go_back()
+      in
+      [], parsed_text_length, Some go_back
+  | TA.Redo (_, Some i) ->  [], parsed_text_length, 
+      Some (fun () -> for j = 1 to i do advance () done)
+  | TA.Redo (_, None) ->   [], parsed_text_length, 
+      Some (fun () -> advance ())
+  | TA.Undo (_, Some i) ->  [], parsed_text_length, 
+      Some (fun () -> for j = 1 to i do script#retract () done)
+  | TA.Undo (_, None) -> [], parsed_text_length, 
+      Some (fun () -> script#retract ()) *)
+  (* TODO *)
+  | TA.Quit _ -> failwith "not implemented"
+  | TA.Print (_,kind) -> failwith "not implemented"
+  | TA.Search_pat (_, search_kind, str) -> failwith "not implemented"
+  | TA.Search_term (_, search_kind, term) -> failwith "not implemented"
 
-    method private forward () = ignore (self#_forward ())
+                                
+let eval_executable status (mathviewer:MatitaTypes.mathViewer) urichooser
+user_goal parsed_text script ex =
+  let module TA = TacticAst in
+  let module TAPp = TacticAstPp in
+  let module MD = MatitaDisambiguator in
+  let parsed_text_length = String.length parsed_text in
+  match ex with
+  | TA.Command (loc, _) | TA.Tactical (loc, _) ->
+      eval_with_engine status user_goal parsed_text (TA.Executable (loc, ex))
+  | TA.Macro (_,mac) ->
+      eval_macro status mathviewer urichooser parsed_text script mac
 
-    method private back () =
-        (* clean history backward until the first theorem, return offset before
-        * it and remaning history *)
-      let rec flush_theorem = function
-        | (Some `Theorem, offset) :: tl -> offset, tl
-        | _ :: tl -> flush_theorem tl
-        | [] -> assert false
+let rec eval_statement status (mathviewer:MatitaTypes.mathViewer) urichooser
+user_goal script s =
+  if Pcre.pmatch ~rex:only_dust_RE s then raise Margin;
+  let st = CicTextualParser2.parse_statement (Stream.of_string s) in
+  let text_of_loc loc =
+    let parsed_text_length = snd (CicAst.loc_of_floc loc) in
+    let parsed_text = safe_substring s 0 parsed_text_length in
+    parsed_text, parsed_text_length
+  in
+  match st with
+  | TacticAst.Comment (loc,_)-> 
+      let parsed_text, parsed_text_length = text_of_loc loc in
+      let remain_len = String.length s - parsed_text_length in
+      let s = String.sub s parsed_text_length remain_len in
+      let s,len = 
+        eval_statement status mathviewer urichooser user_goal script s 
       in
-      match items with
-      | [] -> raise (Script_failure "at top")
-      | (item, last_offset) :: tl ->
-          undo_item item;
-          let (last_offset, tl) =
-            (* if undoing a qed, go back before corresponding theorem *)
-            match item with
-            | Some (`Qed _) -> flush_theorem tl
-            | _ -> last_offset, tl
-          in
-          items <- tl;
-          self#lockScript last_offset
-
-  end
-
-let script ~interpreter = new script ~interpreter ()
+      (match s with
+      | (status, text) :: tl ->
+        ((status, parsed_text ^ text)::tl), (parsed_text_length + len)
+      | [] -> [], 0)
+  | TacticAst.Executable (loc, ex) ->
+      let parsed_text, parsed_text_length = text_of_loc loc in
+      eval_executable 
+        status mathviewer urichooser user_goal parsed_text script ex
+  
+let fresh_script_id =
+  let i = ref 0 in
+  fun () -> incr i; !i
+
+class script ~(buffer: GText.buffer) ~(init: MatitaTypes.status) 
+              ~(mathviewer: MatitaTypes.mathViewer) 
+              ~set_star
+              ~urichooser () =
+object (self)
+  val mutable filename = None
+  val scriptId = fresh_script_id ()
+  method private getFilename =
+    match filename with Some f -> f | _ -> assert false
+  method private ppFilename =
+    match filename with Some f -> f | None -> sprintf ".unnamed%d.ma" scriptId
+  
+  initializer 
+    ignore(GMain.Timeout.add ~ms:30000 
+       ~callback:(fun _ -> self#_saveToBackuptFile ();true));
+    set_star self#ppFilename false;
+    ignore(buffer#connect#modified_changed 
+       (fun _ -> if buffer#modified then 
+          set_star self#ppFilename true 
+        else 
+          set_star self#ppFilename false));
+    self#reset ()
+
+  val mutable statements = [];    (** executed statements *)
+  val mutable history = [ init ];
+    (** list of states before having executed statements. Head element of this
+      * list is the current state, last element is the state at the beginning of
+      * the script.
+      * Invariant: this list length is 1 + length of statements *)
+
+  (** goal as seen by the user (i.e. metano corresponding to current tab) *)
+  val mutable userGoal = ~-1
+
+
+  (** text mark and tag representing locked part of a script *)
+  val locked_mark =
+    buffer#create_mark ~name:"locked" ~left_gravity:true buffer#start_iter
+  val locked_tag = buffer#create_tag [`BACKGROUND "lightblue"; `EDITABLE false]
+
+    (* history can't be empty, the invariant above grant that it contains at
+     * least the init status *)
+  method status = match history with hd :: _ -> hd | _ -> assert false
+
+  method private _advance ?statement () =
+    let s = match statement with Some s -> s | None -> self#getFuture in
+    MatitaLog.debug ("evaluating: " ^ first_line s ^ " ...");
+    let (entries, parsed_len) = 
+      eval_statement self#status mathviewer urichooser userGoal self s in
+    let (new_statuses, new_statements) = List.split entries in
+(*
+prerr_endline "evalStatement returned";
+List.iter (fun s -> prerr_endline ("'" ^ s ^ "'")) new_statements;
+*)
+    history <- List.rev new_statuses @ history;
+    statements <- List.rev new_statements @ statements;
+    let start = buffer#get_iter_at_mark (`MARK locked_mark) in
+    let new_text = String.concat "" new_statements in
+    if new_text <> String.sub s 0 parsed_len then
+      begin
+(*       prerr_endline ("new:" ^ new_text); *)
+(*       prerr_endline ("s:" ^ String.sub s 0 parsed_len); *)
+      let stop = start#copy#forward_chars parsed_len in
+      buffer#delete ~start ~stop;
+      buffer#insert ~iter:start new_text;
+(*       prerr_endline "AUTOMATICALLY MODIFIED!!!!!" *)
+      end;
+    self#moveMark (String.length new_text)
+
+  method private _retract () =
+    match statements, history with
+    | last_statement :: _, cur_status :: prev_status :: _ ->
+        MatitaSync.time_travel ~present:cur_status ~past:prev_status;
+        statements <- List.tl statements;
+        history <- List.tl history;
+        self#moveMark (- (String.length last_statement));
+    | _ -> raise Margin
+
+  method advance ?statement () =
+    try
+      self#_advance ?statement ()
+    with Margin -> ()
+
+  method retract () = try self#_retract () with Margin -> ()
+
+  method private getFuture =
+    buffer#get_text ~start:(buffer#get_iter_at_mark (`MARK locked_mark))
+      ~stop:buffer#end_iter ()
+
+  (** @param rel_offset relative offset from current position of locked_mark *)
+  method private moveMark rel_offset =
+    let mark = `MARK locked_mark in
+    let old_insert = buffer#get_iter_at_mark `INSERT in
+    buffer#remove_tag locked_tag ~start:buffer#start_iter ~stop:buffer#end_iter;
+    let current_mark_pos = buffer#get_iter_at_mark mark in
+    let new_mark_pos =
+      match rel_offset with
+      | 0 -> current_mark_pos
+      | n when n > 0 -> current_mark_pos#forward_chars n
+      | n (* when n < 0 *) -> current_mark_pos#backward_chars (abs n)
+    in
+    buffer#move_mark mark ~where:new_mark_pos;
+    buffer#apply_tag locked_tag ~start:buffer#start_iter ~stop:new_mark_pos;
+    buffer#move_mark `INSERT old_insert;
+    self#notify
+
+  val mutable observers = []
+
+  method addObserver (o: MatitaTypes.status -> unit) =
+    observers <- o :: observers
+
+  method private notify =
+    let status = self#status in
+    List.iter (fun o -> o status) observers
+
+  method loadFromFile () =
+    buffer#set_text (MatitaMisc.input_file self#getFilename);
+    self#goto_top;
+    buffer#set_modified false
+    
+  method assignFileName file =
+    filename <- Some file;
+    
+  method saveToFile () =
+    let oc = open_out self#getFilename in
+    output_string oc (buffer#get_text ~start:buffer#start_iter
+                        ~stop:buffer#end_iter ());
+    close_out oc;
+    buffer#set_modified false
+  
+  method private _saveToBackuptFile () =
+    if buffer#modified then
+      begin
+        let f = self#ppFilename ^ "~" in
+        let oc = open_out f in
+        output_string oc (buffer#get_text ~start:buffer#start_iter
+                            ~stop:buffer#end_iter ());
+        close_out oc;
+        MatitaLog.debug ("backup " ^ f ^ " saved")                    
+      end
+  
+  method private goto_top =
+    MatitaSync.time_travel ~present:self#status ~past:init;
+    statements <- [];
+    history <- [ init ];
+    userGoal <- ~-1;
+    self#notify;
+    buffer#remove_tag locked_tag ~start:buffer#start_iter ~stop:buffer#end_iter;
+    buffer#move_mark (`MARK locked_mark) ~where:buffer#start_iter
+
+  method reset () =
+    self#goto_top;
+    buffer#delete ~start:buffer#start_iter ~stop:buffer#end_iter
+
+  method goto (pos: [`Top | `Bottom | `Cursor]) () =
+    match pos with
+    | `Top -> self#goto_top
+    | `Bottom ->
+        (try while true do self#_advance () done with Margin -> ())
+    | `Cursor ->
+        let locked_iter () = buffer#get_iter_at_mark (`NAME "locked") in
+        let cursor_iter () = buffer#get_iter_at_mark `INSERT in
+        let rec forward_until_cursor () = (* go forward until locked > cursor *)
+          self#_advance ();
+          if (locked_iter ())#compare (cursor_iter ()) < 0 then
+            forward_until_cursor ()
+        in
+        let rec back_until_cursor () = (* go backward until locked < cursor *)
+          self#_retract ();
+          if (locked_iter ())#compare (cursor_iter ()) > 0 then
+            back_until_cursor ()
+        in
+        let cmp = (locked_iter ())#compare (cursor_iter ()) in
+        (try
+          if cmp < 0 then       (* locked < cursor *)
+            forward_until_cursor ()
+          else if cmp > 0 then  (* locked > cursor *)
+            back_until_cursor ()
+          else                  (* cursor = locked *)
+              ()
+        with Margin -> ())
+
+  method onGoingProof () =
+    match self#status.proof_status with
+    | No_proof | Proof _ -> false
+    | Incomplete_proof _ -> true
+    | Intermediate _ -> assert false
+
+  method proofStatus = MatitaMisc.get_proof_status self#status
+  method proofMetasenv = MatitaMisc.get_proof_metasenv self#status
+  method proofContext = MatitaMisc.get_proof_context self#status
+  method setGoal n = userGoal <- n
+
+  (* debug *)
+  method dump () =
+    MatitaLog.debug "script status:";
+    MatitaLog.debug ("history size: " ^ string_of_int (List.length history));
+    MatitaLog.debug (sprintf "%d statements:" (List.length statements));
+    List.iter MatitaLog.debug statements;
+    MatitaLog.debug ("Current file name: " ^
+      (match filename with None -> "[ no name ]" | Some f -> f));
+
+end
+
+let _script = ref None
+
+let script ~buffer ~init ~mathviewer ~urichooser ~set_star () =
+  let s = new script ~buffer ~init ~mathviewer ~urichooser ~set_star () in
+  _script := Some s;
+  s
+
+let instance () = match !_script with None -> assert false | Some s -> s
+