path: root/ide/coq.ml

(************************************************************************)
(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
(* <O___,, *   INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2011     *)
(*   \VV/  **************************************************************)
(*    //   *      This file is distributed under the terms of the       *)
(*         *       GNU Lesser General Public License Version 2.1        *)
(************************************************************************)

(* $Id: coq.ml 14641 2011-11-06 11:59:10Z herbelin $ *)

open Vernac
open Vernacexpr
open Pfedit
open Pp
open Util
open Names
open Term
open Printer
open Environ
open Evarutil
open Evd
open Decl_mode
open Hipattern
open Tacmach
open Reductionops
open Termops
open Namegen
open Ideutils

let msg m =
  let b =  Buffer.create 103 in
  Pp.msg_with (Format.formatter_of_buffer b) m;
  Buffer.contents b

let msgnl m =
  (msg m)^"\n"

let init () =
  (* To hide goal in lower window.
     Problem: should not hide "xx is assumed"
     messages *)
(**)
  Flags.make_silent true;
  (* don't set a too large undo stack because Edit.create allocates an array *)
  Pfedit.set_undo (Some 5000);
(**)
  Coqtop.init_ide ()


let i = ref 0

let get_version_date () =
  let date =
    if Glib.Utf8.validate Coq_config.date
    then Coq_config.date
    else "<date not printable>" in
  try
    let ch = open_in (Coq_config.coqsrc^"/revision") in
    let ver = input_line ch in
    let rev = input_line ch in
    (ver,rev)
  with _ -> (Coq_config.version,date)

let short_version () =
  let (ver,date) = get_version_date () in
  Printf.sprintf "The Coq Proof Assistant, version %s (%s)\n" ver date

let version () =
  let (ver,date) = get_version_date () in
    Printf.sprintf
      "The Coq Proof Assistant, version %s (%s)\
       \nArchitecture %s running %s operating system\
       \nGtk version is %s\
       \nThis is the %s version (%s is the best one for this architecture and OS)\
       \n"
      ver date
      Coq_config.arch Sys.os_type
      (let x,y,z = GMain.Main.version in Printf.sprintf "%d.%d.%d" x y z)
    (if Mltop.is_native then "native" else "bytecode")
    (if Coq_config.best="opt" then "native" else "bytecode")

let is_in_coq_lib dir =
  prerr_endline ("Is it a coq theory ? : "^dir);
  let is_same_file = same_file dir in
  List.exists
    (fun s ->
      let fdir =
        Filename.concat (Envars.coqlib ()) (Filename.concat "theories" s) in
      prerr_endline (" Comparing to: "^fdir);
      if is_same_file fdir then (prerr_endline " YES";true)
      else (prerr_endline"NO";false))
    Coq_config.theories_dirs

let is_in_loadpath dir =
  Library.is_in_load_paths (System.physical_path_of_string dir)

let is_in_coq_path f =
  try
  let base = Filename.chop_extension (Filename.basename f) in
  let _ = Library.locate_qualified_library false
	    (Libnames.make_qualid Names.empty_dirpath
	       (Names.id_of_string base)) in
  prerr_endline (f ^ " is in coq path");
  true
  with _ ->
    prerr_endline (f ^ " is NOT in coq path");
    false

let is_in_proof_mode () =
  match Decl_mode.get_current_mode () with
      Decl_mode.Mode_none -> false
    | _ -> true

let user_error_loc l s =
  raise (Stdpp.Exc_located (l, Util.UserError ("CoqIde", s)))

type printing_state = {
  mutable printing_implicit : bool;
  mutable printing_coercions : bool;
  mutable printing_raw_matching : bool;
  mutable printing_no_notation : bool;
  mutable printing_all : bool;
  mutable printing_evar_instances : bool;
  mutable printing_universes : bool;
  mutable printing_full_all : bool
}

let printing_state = {
  printing_implicit = false;
  printing_coercions = false;
  printing_raw_matching = false;
  printing_no_notation = false;
  printing_all = false;
  printing_evar_instances = false;
  printing_universes = false;
  printing_full_all = false;
}

let printing_implicit_data = ["Printing";"Implicit"], false
let printing_coercions_data = ["Printing";"Coercions"], false
let printing_raw_matching_data = ["Printing";"Matching"], true
let printing_no_synth_data = ["Printing";"Synth"], true
let printing_no_notation_data = ["Printing";"Notations"], true
let printing_all_data = ["Printing";"All"], false
let printing_evar_instances_data = ["Printing";"Existential";"Instances"],false
let printing_universes_data = ["Printing";"Universes"], false

let known_options = ref []

let prepare_option (l,dft) =
  known_options := l :: !known_options;
  let set = (String.concat " " ("Set"::l)) ^ "." in
  let unset = (String.concat " " ("Unset"::l)) ^ "." in
  if dft then unset,set else set,unset

let coqide_known_option table = List.mem table !known_options

let with_printing_implicit = prepare_option printing_implicit_data
let with_printing_coercions = prepare_option printing_coercions_data
let with_printing_raw_matching = prepare_option printing_raw_matching_data
let with_printing_no_synth = prepare_option printing_no_synth_data
let with_printing_no_notation = prepare_option printing_no_notation_data
let with_printing_all = prepare_option printing_all_data
let with_printing_evar_instances = prepare_option printing_evar_instances_data
let with_printing_universes = prepare_option printing_universes_data

let make_option_commands () =
  let p = printing_state in
  (if p.printing_implicit then [with_printing_implicit] else [])@
  (if p.printing_coercions then [with_printing_coercions] else [])@
  (if p.printing_raw_matching then [with_printing_raw_matching;with_printing_no_synth] else [])@
  (if p.printing_no_notation then [with_printing_no_notation] else [])@
  (if p.printing_all then [with_printing_all] else [])@
  (if p.printing_evar_instances then [with_printing_evar_instances] else [])@
  (if p.printing_universes then [with_printing_universes] else [])@
  (if p.printing_full_all then [with_printing_all;with_printing_evar_instances;with_printing_universes] else [])

let make_option_commands () =
  let l = make_option_commands () in
  List.iter (fun (a,b) -> prerr_endline a; prerr_endline b) l;
  l

type command_attribute =
    NavigationCommand | QueryCommand | DebugCommand | KnownOptionCommand
  | OtherStatePreservingCommand | GoalStartingCommand | SolveCommand
  | ProofEndingCommand

let rec attribute_of_vernac_command = function
  (* Control *)
  | VernacTime com -> attribute_of_vernac_command com
  | VernacTimeout(_,com) -> attribute_of_vernac_command com
  | VernacFail com -> attribute_of_vernac_command com
  | VernacList _ -> [] (* unsupported *)
  | VernacLoad _ -> []

  (* Syntax *)
  | VernacTacticNotation _ -> []
  | VernacSyntaxExtension _ -> []
  | VernacDelimiters _ -> []
  | VernacBindScope _ -> []
  | VernacOpenCloseScope _ -> []
  | VernacArgumentsScope _ -> []
  | VernacInfix _ -> []
  | VernacNotation _ -> []

  (* Gallina *)
  | VernacDefinition (_,_,DefineBody _,_) -> []
  | VernacDefinition (_,_,ProveBody _,_) -> [GoalStartingCommand]
  | VernacStartTheoremProof _ -> [GoalStartingCommand]
  | VernacEndProof _ -> [ProofEndingCommand]
  | VernacExactProof _ -> [ProofEndingCommand]

  | VernacAssumption _ -> []
  | VernacInductive _ -> []
  | VernacFixpoint _ -> []
  | VernacCoFixpoint _ -> []
  | VernacScheme _ -> []
  | VernacCombinedScheme _ -> []

  (* Modules *)
  | VernacDeclareModule _ -> []
  | VernacDefineModule _  -> []
  | VernacDeclareModuleType _ -> []
  | VernacInclude _ -> []

  (* Gallina extensions *)
  | VernacBeginSection _ -> []
  | VernacEndSegment _ -> []
  | VernacRequire _ -> []
  | VernacImport _ -> []
  | VernacCanonical _ -> []
  | VernacCoercion _ -> []
  | VernacIdentityCoercion _ -> []

  (* Type classes *)
  | VernacInstance _ -> []
  | VernacContext _ -> []
  | VernacDeclareInstance _ -> []
  | VernacDeclareClass _ -> []

  (* Solving *)
  | VernacSolve _ -> [SolveCommand]
  | VernacSolveExistential _ -> [SolveCommand]

  (* MMode *)
  | VernacDeclProof -> [SolveCommand]
  | VernacReturn -> [SolveCommand]
  | VernacProofInstr _ -> [SolveCommand]

  (* Auxiliary file and library management *)
  | VernacRequireFrom _ -> []
  | VernacAddLoadPath _ -> []
  | VernacRemoveLoadPath _ -> []
  | VernacAddMLPath _ -> []
  | VernacDeclareMLModule _ -> []
  | VernacChdir _ -> [OtherStatePreservingCommand]

  (* State management *)
  | VernacWriteState _ -> []
  | VernacRestoreState _ -> []

  (* Resetting *)
  | VernacRemoveName _ -> [NavigationCommand]
  | VernacResetName _ -> [NavigationCommand]
  | VernacResetInitial -> [NavigationCommand]
  | VernacBack _ -> [NavigationCommand]
  | VernacBackTo _ -> [NavigationCommand]

  (* Commands *)
  | VernacDeclareTacticDefinition _ -> []
  | VernacCreateHintDb _ -> []
  | VernacHints _ -> []
  | VernacSyntacticDefinition _ -> []
  | VernacDeclareImplicits _ -> []
  | VernacDeclareReduction _ -> []
  | VernacReserve _ -> []
  | VernacGeneralizable _ -> []
  | VernacSetOpacity _ -> []
  | VernacSetOption (_,["Ltac";"Debug"], _) -> [DebugCommand]
  | VernacSetOption (_,o,BoolValue true) | VernacUnsetOption (_,o) ->
      if coqide_known_option o then [KnownOptionCommand] else []
  | VernacSetOption _ -> []
  | VernacRemoveOption _ -> []
  | VernacAddOption _ -> []
  | VernacMemOption _ -> [QueryCommand]

  | VernacPrintOption _ -> [QueryCommand]
  | VernacCheckMayEval _ -> [QueryCommand]
  | VernacGlobalCheck _ -> [QueryCommand]
  | VernacPrint _ -> [QueryCommand]
  | VernacSearch _ -> [QueryCommand]
  | VernacLocate _ -> [QueryCommand]

  | VernacComments _ -> [OtherStatePreservingCommand]
  | VernacNop -> [OtherStatePreservingCommand]

  (* Proof management *)
  | VernacGoal _ -> [GoalStartingCommand]

  | VernacAbort _ -> []
  | VernacAbortAll -> [NavigationCommand]
  | VernacRestart -> [NavigationCommand]
  | VernacSuspend -> [NavigationCommand]
  | VernacResume _ -> [NavigationCommand]
  | VernacUndo _ -> [NavigationCommand]
  | VernacUndoTo _ -> [NavigationCommand]
  | VernacBacktrack _ -> [NavigationCommand]

  | VernacFocus _ -> [SolveCommand]
  | VernacUnfocus -> [SolveCommand]
  | VernacGo _ -> []
  | VernacShow _ -> [OtherStatePreservingCommand]
  | VernacCheckGuard -> [OtherStatePreservingCommand]
  | VernacProof (Tacexpr.TacId []) -> [OtherStatePreservingCommand]
  | VernacProof _ -> []

  (* Toplevel control *)
  | VernacToplevelControl _ -> []

  (* Extensions *)
  | VernacExtend ("Subtac_Obligations", _) -> [GoalStartingCommand]
  | VernacExtend _ -> []

let is_vernac_goal_starting_command com =
  List.mem GoalStartingCommand (attribute_of_vernac_command com)

let is_vernac_navigation_command com =
  List.mem NavigationCommand (attribute_of_vernac_command com)

let is_vernac_query_command com =
  List.mem QueryCommand (attribute_of_vernac_command com)

let is_vernac_known_option_command com =
  List.mem KnownOptionCommand (attribute_of_vernac_command com)

let is_vernac_debug_command com =
  List.mem DebugCommand (attribute_of_vernac_command com)

let is_vernac_goal_printing_command com =
  let attribute = attribute_of_vernac_command com in
  List.mem GoalStartingCommand attribute or
  List.mem SolveCommand attribute

let is_vernac_state_preserving_command com =
  let attribute = attribute_of_vernac_command com in
  List.mem OtherStatePreservingCommand attribute or
  List.mem QueryCommand attribute

let is_vernac_tactic_command com =
  List.mem SolveCommand (attribute_of_vernac_command com)

let is_vernac_proof_ending_command com =
  List.mem ProofEndingCommand (attribute_of_vernac_command com)

type undo_info = identifier list

let undo_info () = Pfedit.get_all_proof_names ()

type reset_mark = Libnames.object_name

type reset_status =
  | NoReset
  | ResetAtSegmentStart of Names.identifier
  | ResetAtRegisteredObject of reset_mark

type reset_info = {
  status : reset_status;
  proofs : identifier list;
  cur_prf : (identifier * int) option;
  loc_ast : Util.loc * Vernacexpr.vernac_expr;
}

let compute_reset_info loc_ast = 
  let status,cur_prf = match snd loc_ast with
    | com when is_vernac_proof_ending_command com -> NoReset,None
    | VernacEndSegment _ -> NoReset,None
    | com when is_vernac_tactic_command com ->
        NoReset,Some (Pfedit.get_current_proof_name (), Pfedit.current_proof_depth ())
    | _ ->
        (match Lib.has_top_frozen_state () with
           | Some sp -> 
               prerr_endline ("On top of state "^Libnames.string_of_path (fst sp));
               ResetAtRegisteredObject sp,None
           | None -> NoReset,None)
  in
  { status = status;
    proofs = Pfedit.get_all_proof_names ();
    cur_prf = cur_prf;
    loc_ast = loc_ast; 
  }

let reset_initial () =
  prerr_endline "Reset initial called";
  Vernacentries.abort_refine Lib.reset_initial ()

let reset_to sp =
      prerr_endline
        ("Reset called with state "^(Libnames.string_of_path (fst sp)));
      Lib.reset_to_state sp

let raw_interp s =
  Vernac.raw_do_vernac (Pcoq.Gram.parsable (Stream.of_string s))

let interp_with_options verbosely options s =
  prerr_endline "Starting interp...";
  prerr_endline s;
  let pa = Pcoq.Gram.parsable (Stream.of_string s) in
  let pe = Pcoq.Gram.Entry.parse Pcoq.main_entry pa in
  (* Temporary hack to make coqide.byte work (WTF???) - now with less screen
  * pollution *)
  (try Pervasives.prerr_string " \r"; Pervasives.flush stderr with _ -> ());
  match pe with
    | None -> assert false
    | Some((loc,vernac) as last) ->
	if is_vernac_debug_command vernac then
	  user_error_loc loc (str "Debug mode not available within CoqIDE");
	if is_vernac_navigation_command vernac then
	  user_error_loc loc (str "Use CoqIDE navigation instead");
	if is_vernac_known_option_command vernac then
	  user_error_loc loc (str "Use CoqIDE display menu instead");
	if is_vernac_query_command vernac then
	  flash_info
	    "Warning: query commands should not be inserted in scripts";
	if not (is_vernac_goal_printing_command vernac) then
	  (* Verbose if in small step forward and not a tactic *)
	  Flags.make_silent (not verbosely);
	let reset_info = compute_reset_info last in
	List.iter (fun (set_option,_) -> raw_interp set_option) options;
	raw_interp s;
	Flags.make_silent true;
	List.iter (fun (_,unset_option) -> raw_interp unset_option) options;
	prerr_endline ("...Done with interp of : "^s);
	reset_info

let interp verbosely phrase =
  interp_with_options verbosely (make_option_commands ()) phrase

let interp_and_replace s =
  let result = interp false s in
  let msg = read_stdout () in
  result,msg

let rec is_pervasive_exn = function
  | Out_of_memory | Stack_overflow | Sys.Break -> true
  | Error_in_file (_,_,e) -> is_pervasive_exn e
  | Stdpp.Exc_located (_,e) -> is_pervasive_exn e
  | DuringCommandInterp (_,e) -> is_pervasive_exn e
  | _ -> false

let print_toplevel_error exc =
  let (dloc,exc) =
    match exc with
      | DuringCommandInterp (loc,ie) ->
          if loc = dummy_loc then (None,ie) else (Some loc, ie)
      | _ -> (None, exc)
  in
  let (loc,exc) =
    match exc with
      | Stdpp.Exc_located (loc, ie) -> (Some loc),ie
      | Error_in_file (s, (_,fname, loc), ie) -> None, ie
      | _ -> dloc,exc
  in
  match exc with
    | End_of_input  -> 	str "Please report: End of input",None
    | Vernacexpr.Drop ->  str "Drop is not allowed by coqide!",None
    | Vernacexpr.Quit -> str "Quit is not allowed by coqide! Use menus.",None
    | _ ->
	(try Cerrors.explain_exn exc with e ->
	   str "Failed to explain error. This is an internal Coq error. Please report.\n"
	   ++ str (Printexc.to_string  e)),
	(if is_pervasive_exn exc then None else loc)

let process_exn e = let s,loc= print_toplevel_error e in (msgnl s,loc)

let interp_last last =
  prerr_string "*";
  try
    vernac_com Vernacentries.interp last;
    Lib.add_frozen_state()
  with e ->
    let s,_ = process_exn e in prerr_endline ("Replay during undo failed because: "^s);
    raise e

let push_phrase cmd_stk reset_info ide_payload =
  Stack.push (ide_payload,reset_info) cmd_stk

type backtrack =
  | BacktrackToNextActiveMark
  | BacktrackToMark of reset_mark
  | NoBacktrack

let apply_reset = function
  | BacktrackToMark mark -> reset_to mark
  | NoBacktrack -> ()
  | BacktrackToNextActiveMark -> assert false

let rewind sequence cmd_stk =
  let undo_ops = Hashtbl.create 31 in
  let current_proofs = undo_info () in
  let pop_state cont seq coq reset_op prev_proofs curprf =
    prerr_endline "pop";
    let curprf =
      Option.map
        (fun (curprf,depth) ->
           (if Hashtbl.mem undo_ops curprf then Hashtbl.replace else Hashtbl.add)
             undo_ops curprf depth;
           curprf)
        coq.cur_prf in
    let reset_op =
      match coq.status with
        | ResetAtRegisteredObject mark ->
            BacktrackToMark mark
        | _ when is_vernac_state_preserving_command (snd coq.loc_ast) ->
            reset_op
        | _ when is_vernac_tactic_command (snd coq.loc_ast) ->
            reset_op
        | _ ->
            BacktrackToNextActiveMark in
    cont seq reset_op coq.proofs curprf
  in
  let rec do_rewind seq reset_op prev_proofs curprf =
    match seq with
      | [] when ((reset_op <> BacktrackToNextActiveMark) &&
                 (Util.list_subset prev_proofs current_proofs)) ->
          begin
            Hashtbl.iter
              (fun id depth ->
                 if List.mem id prev_proofs then begin
                   Pfedit.resume_proof (Util.dummy_loc,id);
                   Pfedit.undo_todepth depth
                 end)
              undo_ops;
            prerr_endline "OK for undos";
            Option.iter (fun id -> if List.mem id prev_proofs then
                           Pfedit.resume_proof (Util.dummy_loc,id)) curprf;
            prerr_endline "OK for focusing";
            List.iter
              (fun id -> Pfedit.delete_proof (Util.dummy_loc,id))
              (Util.list_subtract current_proofs prev_proofs);
            prerr_endline "OK for aborts";
            apply_reset reset_op;
            prerr_endline "OK for reset"
          end
      | [] ->
          begin
            try 
              let ide,coq = Stack.pop cmd_stk in
              pop_state do_rewind [] coq reset_op prev_proofs curprf;
              prerr_endline "push";
              let reset_info = compute_reset_info coq.loc_ast in
              interp_last coq.loc_ast;
              push_phrase cmd_stk reset_info ide
            with Stack.Empty -> reset_initial ()
          end
      | coq::rem ->
          pop_state do_rewind rem coq reset_op prev_proofs curprf
  in
  do_rewind sequence NoBacktrack current_proofs None

type  tried_tactic =
  | Interrupted
  | Success of int (* nb of goals after *)
  | Failed

type hyp = env * evar_map *
           ((identifier * string) * constr option * constr) *
           (string * string)
type concl = env * evar_map * constr * string
type meta = env * evar_map * string
type goal = hyp list * concl

let prepare_hyp sigma env ((i,c,d) as a) =
  env, sigma,
  ((i,string_of_id i),c,d),
  (msg (pr_var_decl env a), msg (pr_ltype_env env d))

let prepare_hyps sigma env =
  assert (rel_context env = []);
  let hyps =
    fold_named_context
      (fun env d acc -> let hyp = prepare_hyp sigma env d in hyp :: acc)
      env ~init:[]
  in
  List.rev hyps

let prepare_goal_main sigma g =
  let env = evar_env g in
  (prepare_hyps sigma env,
   (env, sigma, g.evar_concl, msg (pr_ltype_env_at_top env g.evar_concl)))

let prepare_goal sigma g =
  let options = make_option_commands () in
  List.iter (fun (set_option,_) -> raw_interp set_option) options;
  let x = prepare_goal_main sigma g in
  List.iter (fun (_,unset_option) -> raw_interp unset_option) options;
  x

let get_current_pm_goal () =
  let pfts = get_pftreestate ()  in
  let gls = try nth_goal_of_pftreestate 1 pfts with _ -> raise Not_found in
  let sigma= sig_sig gls in
  let gl = sig_it gls in
    prepare_goal sigma gl

let get_current_goals () =
    let pfts = get_pftreestate () in
    let gls = fst (Refiner.frontier (Tacmach.proof_of_pftreestate pfts)) in
    let sigma = Tacmach.evc_of_pftreestate pfts in
    List.map (prepare_goal sigma) gls

let print_no_goal () =
  (* Fall back on standard coq goal printer for completed goal printing *)
  msg (pr_open_subgoals ())

let hyp_menu (env, sigma, ((coqident,ident),_,ast),(s,pr_ast)) =
  [("clear "^ident),("clear "^ident^".");

   ("apply "^ident),
   ("apply "^ident^".");

   ("exact "^ident),
   ("exact "^ident^".");

   ("generalize "^ident),
   ("generalize "^ident^".");

   ("absurd <"^ident^">"),
   ("absurd "^
    pr_ast
    ^".") ] @

   (if is_equality_type ast then
      [ "discriminate "^ident, "discriminate "^ident^".";
	"injection "^ident, "injection "^ident^"." ]
    else
      []) @

   (let _,t = splay_prod env sigma ast in
    if is_equality_type t then
      [ "rewrite "^ident, "rewrite "^ident^".";
	"rewrite <- "^ident, "rewrite <- "^ident^"." ]
    else
      []) @

  [("elim "^ident),
   ("elim "^ident^".");

   ("inversion "^ident),
   ("inversion "^ident^".");

   ("inversion clear "^ident),
   ("inversion_clear "^ident^".")]

let concl_menu (_,_,concl,_) =
  let is_eq = is_equality_type concl in
  ["intro", "intro.";
   "intros", "intros.";
   "intuition","intuition." ] @

   (if is_eq then
      ["reflexivity", "reflexivity.";
       "discriminate", "discriminate.";
       "symmetry", "symmetry." ]
    else
      []) @

  ["assumption" ,"assumption.";
   "omega", "omega.";
   "ring", "ring.";
   "auto with *", "auto with *.";
   "eauto with *", "eauto with *.";
   "tauto", "tauto.";
   "trivial", "trivial.";
   "decide equality", "decide equality.";

   "simpl", "simpl.";
   "subst", "subst.";

   "red", "red.";
   "split", "split.";
   "left", "left.";
   "right", "right.";
  ]


let id_of_name = function
  | Names.Anonymous -> id_of_string "x"
  | Names.Name x -> x

let make_cases s =
  let qualified_name = Libnames.qualid_of_string s in
  let glob_ref = Nametab.locate qualified_name in
  match glob_ref with
    | Libnames.IndRef i ->
	let {Declarations.mind_nparams = np},
	{Declarations.mind_consnames = carr ;
	 Declarations.mind_nf_lc = tarr }
	= Global.lookup_inductive i
	in
	Util.array_fold_right2
	  (fun n t l ->
	     let (al,_) = Term.decompose_prod t in
	     let al,_ = Util.list_chop (List.length al - np) al in
	     let rec rename avoid = function
	       | [] -> []
	       | (n,_)::l ->
		   let n' = next_ident_away_in_goal
			      (id_of_name n)
			      avoid
		   in (string_of_id n')::(rename (n'::avoid) l)
	     in
	     let al' = rename [] (List.rev al) in
	     (string_of_id n :: al') :: l
	  )
	  carr
	  tarr
	  []
    | _ -> raise Not_found

let current_status () =
  let path = msg (Libnames.pr_dirpath (Lib.cwd ())) in
  let path = if path = "Top" then "Ready" else "Ready in " ^ String.sub path 4 (String.length path - 4) in
  try
    path ^ ", proving " ^ (Names.string_of_id (Pfedit.get_current_proof_name ()))
  with _ -> path