(************************************************************************)
(*         *   The Coq Proof Assistant / The Coq Development Team       *)
(*  v      *         Copyright INRIA, CNRS and contributors             *)
(* <O___,, * (see version control and CREDITS file for authors & dates) *)
(*   \VV/  **************************************************************)
(*    //   *    This file is distributed under the terms of the         *)
(*         *     GNU Lesser General Public License Version 2.1          *)
(*         *     (see LICENSE file for the text of the license)         *)
(************************************************************************)

open Pp
open Util
open CAst
open CErrors
open Names
open Libnames
open Libobject
open Nametab
open Tac2expr
open Tac2print
open Tac2intern

(** Grammar entries *)

module Pltac =
struct
let ltac2_expr = Pcoq.Entry.create "ltac2_expr"
let tac2expr = ltac2_expr
let tac2expr_in_env = Pcoq.Entry.create "tac2expr_in_env"

let q_ident = Pcoq.Entry.create "q_ident"
let q_bindings = Pcoq.Entry.create "q_bindings"
let q_with_bindings = Pcoq.Entry.create "q_with_bindings"
let q_intropattern = Pcoq.Entry.create "q_intropattern"
let q_intropatterns = Pcoq.Entry.create "q_intropatterns"
let q_destruction_arg = Pcoq.Entry.create "q_destruction_arg"
let q_induction_clause = Pcoq.Entry.create "q_induction_clause"
let q_conversion = Pcoq.Entry.create "q_conversion"
let q_rewriting = Pcoq.Entry.create "q_rewriting"
let q_clause = Pcoq.Entry.create "q_clause"
let q_dispatch = Pcoq.Entry.create "q_dispatch"
let q_occurrences = Pcoq.Entry.create "q_occurrences"
let q_reference = Pcoq.Entry.create "q_reference"
let q_strategy_flag = Pcoq.Entry.create "q_strategy_flag"
let q_constr_matching = Pcoq.Entry.create "q_constr_matching"
let q_goal_matching = Pcoq.Entry.create "q_goal_matching"
let q_hintdb = Pcoq.Entry.create "q_hintdb"
let q_move_location = Pcoq.Entry.create "q_move_location"
let q_pose = Pcoq.Entry.create "q_pose"
let q_assert = Pcoq.Entry.create "q_assert"
end

let () =
  let entries = [
    Pcoq.AnyEntry Pltac.ltac2_expr;
  ] in
  Pcoq.register_grammars_by_name "ltac2" entries

(** Tactic definition *)

type tacdef = {
  tacdef_local : bool;
  tacdef_mutable : bool;
  tacdef_expr : glb_tacexpr;
  tacdef_type : type_scheme;
  tacdef_deprecation : Deprecation.t option;
}

let perform_tacdef visibility ((sp, kn), def) =
  let () = if not def.tacdef_local then Tac2env.push_ltac visibility sp (TacConstant kn) in
  let data = {
    Tac2env.gdata_expr = def.tacdef_expr;
    gdata_type = def.tacdef_type;
    gdata_mutable = def.tacdef_mutable;
    gdata_deprecation = def.tacdef_deprecation;
  } in
  Tac2env.define_global kn data

let load_tacdef i obj = perform_tacdef (Until i) obj
let open_tacdef i obj = perform_tacdef (Exactly i) obj

let cache_tacdef ((sp, kn), def) =
  let () = Tac2env.push_ltac (Until 1) sp (TacConstant kn) in
  let data = {
    Tac2env.gdata_expr = def.tacdef_expr;
    gdata_type = def.tacdef_type;
    gdata_mutable = def.tacdef_mutable;
    gdata_deprecation = def.tacdef_deprecation;
  } in
  Tac2env.define_global kn data

let subst_tacdef (subst, def) =
  let expr' = subst_expr subst def.tacdef_expr in
  let type' = subst_type_scheme subst def.tacdef_type in
  if expr' == def.tacdef_expr && type' == def.tacdef_type then def
  else { def with tacdef_expr = expr'; tacdef_type = type' }

let classify_tacdef o = Substitute o

let inTacDef : tacdef -> obj =
  declare_object {(default_object "TAC2-DEFINITION") with
     cache_function  = cache_tacdef;
     load_function   = load_tacdef;
     open_function   = simple_open open_tacdef;
     subst_function = subst_tacdef;
     classify_function = classify_tacdef}

(** Type definition *)

type typdef = {
  typdef_local : bool;
  typdef_expr : glb_quant_typedef;
}

let change_kn_label kn id =
  let mp = KerName.modpath kn in
  KerName.make mp (Label.of_id id)

let change_sp_label sp id =
  let (dp, _) = Libnames.repr_path sp in
  Libnames.make_path dp id

let push_typedef visibility sp kn (_, def) = match def with
| GTydDef _ ->
  Tac2env.push_type visibility sp kn
| GTydAlg { galg_constructors = cstrs } ->
  (* Register constructors *)
  let iter (c, _) =
    let spc = change_sp_label sp c in
    let knc = change_kn_label kn c in
    Tac2env.push_constructor visibility spc knc
  in
  Tac2env.push_type visibility sp kn;
  List.iter iter cstrs
| GTydRec fields ->
  (* Register fields *)
  let iter (c, _, _) =
    let spc = change_sp_label sp c in
    let knc = change_kn_label kn c in
    Tac2env.push_projection visibility spc knc
  in
  Tac2env.push_type visibility sp kn;
  List.iter iter fields
| GTydOpn ->
  Tac2env.push_type visibility sp kn

let next i =
  let ans = !i in
  let () = incr i in
  ans

let define_typedef kn (params, def as qdef) = match def with
| GTydDef _ ->
  Tac2env.define_type kn qdef
| GTydAlg { galg_constructors = cstrs } ->
  (* Define constructors *)
  let constant = ref 0 in
  let nonconstant = ref 0 in
  let iter (c, args) =
    let knc = change_kn_label kn c in
    let tag = if List.is_empty args then next constant else next nonconstant in
    let data = {
      Tac2env.cdata_prms = params;
      cdata_type = kn;
      cdata_args = args;
      cdata_indx = Some tag;
    } in
    Tac2env.define_constructor knc data
  in
  Tac2env.define_type kn qdef;
  List.iter iter cstrs
| GTydRec fs ->
  (* Define projections *)
  let iter i (id, mut, t) =
    let knp = change_kn_label kn id in
    let proj = {
      Tac2env.pdata_prms = params;
      pdata_type = kn;
      pdata_ptyp = t;
      pdata_mutb = mut;
      pdata_indx = i;
    } in
    Tac2env.define_projection knp proj
  in
  Tac2env.define_type kn qdef;
  List.iteri iter fs
| GTydOpn ->
  Tac2env.define_type kn qdef

let perform_typdef vs ((sp, kn), def) =
  let () = if not def.typdef_local then push_typedef vs sp kn def.typdef_expr in
  define_typedef kn def.typdef_expr

let load_typdef i obj = perform_typdef (Until i) obj
let open_typdef i obj = perform_typdef (Exactly i) obj

let cache_typdef ((sp, kn), def) =
  let () = push_typedef (Until 1) sp kn def.typdef_expr in
  define_typedef kn def.typdef_expr

let subst_typdef (subst, def) =
  let expr' = subst_quant_typedef subst def.typdef_expr in
  if expr' == def.typdef_expr then def else { def with typdef_expr = expr' }

let classify_typdef o = Substitute o

let inTypDef : typdef -> obj =
  declare_object {(default_object "TAC2-TYPE-DEFINITION") with
     cache_function  = cache_typdef;
     load_function   = load_typdef;
     open_function   = simple_open open_typdef;
     subst_function = subst_typdef;
     classify_function = classify_typdef}

(** Type extension *)

type extension_data = {
  edata_name : Id.t;
  edata_args : int glb_typexpr list;
}

type typext = {
  typext_local : bool;
  typext_prms : int;
  typext_type : type_constant;
  typext_expr : extension_data list;
}

let push_typext vis sp kn def =
  let iter data =
    let spc = change_sp_label sp data.edata_name in
    let knc = change_kn_label kn data.edata_name in
    Tac2env.push_constructor vis spc knc
  in
  List.iter iter def.typext_expr

let define_typext kn def =
  let iter data =
    let knc = change_kn_label kn data.edata_name in
    let cdata = {
      Tac2env.cdata_prms = def.typext_prms;
      cdata_type = def.typext_type;
      cdata_args = data.edata_args;
      cdata_indx = None;
    } in
    Tac2env.define_constructor knc cdata
  in
  List.iter iter def.typext_expr

let cache_typext ((sp, kn), def) =
  let () = define_typext kn def in
  push_typext (Until 1) sp kn def

let perform_typext vs ((sp, kn), def) =
  let () = if not def.typext_local then push_typext vs sp kn def in
  define_typext kn def

let load_typext i obj = perform_typext (Until i) obj
let open_typext i obj = perform_typext (Exactly i) obj

let subst_typext (subst, e) =
  let open Mod_subst in
  let subst_data data =
    let edata_args = List.Smart.map (fun e -> subst_type subst e) data.edata_args in
    if edata_args == data.edata_args then data
    else { data with edata_args }
  in
  let typext_type = subst_kn subst e.typext_type in
  let typext_expr = List.Smart.map subst_data e.typext_expr in
  if typext_type == e.typext_type && typext_expr == e.typext_expr then
    e
  else
    { e with typext_type; typext_expr }

let classify_typext o = Substitute o

let inTypExt : typext -> obj =
  declare_object {(default_object "TAC2-TYPE-EXTENSION") with
     cache_function  = cache_typext;
     load_function   = load_typext;
     open_function   = simple_open open_typext;
     subst_function = subst_typext;
     classify_function = classify_typext}

(** Toplevel entries *)

let fresh_var avoid x =
  let bad id =
    Id.Set.mem id avoid ||
    (try ignore (Tac2env.locate_ltac (qualid_of_ident id)); true with Not_found -> false)
  in
  Namegen.next_ident_away_from (Id.of_string x) bad

let extract_pattern_type ({loc;v=p} as pat) = match p with
| CPatCnv (pat, ty) -> pat, Some ty
| CPatVar _ | CPatRef _ -> pat, None

(** Mangle recursive tactics *)
let inline_rec_tactic tactics =
  let avoid = List.fold_left (fun accu ({v=id}, _) -> Id.Set.add id accu) Id.Set.empty tactics in
  let map (id, e) = match e.v with
  | CTacFun (pat, _) -> (id, List.map extract_pattern_type pat, e)
  | _ ->
    user_err ?loc:id.loc (str "Recursive tactic definitions must be functions")
  in
  let tactics = List.map map tactics in
  let map (id, pat, e) =
    let fold_var (avoid, ans) (pat, _) =
      let id = fresh_var avoid "x" in
      let loc = pat.loc in
      (Id.Set.add id avoid, CAst.make ?loc id :: ans)
    in
    (* Fresh variables to abstract over the function patterns *)
    let _, vars = List.fold_left fold_var (avoid, []) pat in
    let map_body ({loc;v=id}, _, e) = CAst.(make ?loc @@ CPatVar (Name id)), e in
    let bnd = List.map map_body tactics in
    let pat_of_id {loc;v=id} = CAst.make ?loc @@ CPatVar (Name id) in
    let var_of_id {loc;v=id} =
      let qid = qualid_of_ident ?loc id in
      CAst.make ?loc @@ CTacRef (RelId qid)
    in
    let loc0 = e.loc in
    let vpat = List.map pat_of_id vars in
    let varg = List.map var_of_id vars in
    let e = CAst.make ?loc:loc0 @@ CTacLet (true, bnd, CAst.make ?loc:loc0 @@ CTacApp (var_of_id id, varg)) in
    (id, CAst.make ?loc:loc0 @@ CTacFun (vpat, e))
  in
  List.map map tactics

let check_lowercase {loc;v=id} =
  if Tac2env.is_constructor (Libnames.qualid_of_ident id) then
    user_err ?loc (str "The identifier " ++ Id.print id ++ str " must be lowercase")

let register_ltac ?deprecation ?(local = false) ?(mut = false) isrec tactics =
  let map ({loc;v=na}, e) =
    let id = match na with
    | Anonymous ->
      user_err ?loc (str "Tactic definition must have a name")
    | Name id -> id
    in
    let () = check_lowercase CAst.(make ?loc id) in
    (CAst.(make ?loc id), e)
  in
  let tactics = List.map map tactics in
  let tactics =
    if isrec then inline_rec_tactic tactics else tactics
  in
  let map ({loc;v=id}, e) =
    let (e, t) = intern ~strict:true [] e in
    let () =
      if not (is_value e) then
        user_err ?loc (str "Tactic definition must be a syntactical value")
    in
    let kn = Lib.make_kn id in
    let exists =
      try let _ = Tac2env.interp_global kn in true with Not_found -> false
    in
    let () =
      if exists then
        user_err ?loc (str "Tactic " ++ Names.Id.print id ++ str " already exists")
    in
    (id, e, t)
  in
  let defs = List.map map tactics in
  let iter (id, e, t) =
    let def = {
      tacdef_local = local;
      tacdef_mutable = mut;
      tacdef_expr = e;
      tacdef_type = t;
      tacdef_deprecation = deprecation;
    } in
    ignore (Lib.add_leaf id (inTacDef def))
  in
  List.iter iter defs

let qualid_to_ident qid =
  if qualid_is_ident qid then CAst.make ?loc:qid.CAst.loc @@ qualid_basename qid
  else user_err ?loc:qid.CAst.loc (str "Identifier expected")

let register_typedef ?(local = false) isrec types =
  let same_name ({v=id1}, _) ({v=id2}, _) = Id.equal id1 id2 in
  let () = match List.duplicates same_name types with
  | [] -> ()
  | ({loc;v=id}, _) :: _ ->
    user_err ?loc (str "Multiple definition of the type name " ++ Id.print id)
  in
  let () =
    let check_existing_type ({v=id},_) =
      let (_, kn) = Lib.make_foname id in
      try let _ = Tac2env.interp_type kn in
        user_err (str "Multiple definition of the type name " ++ Id.print id)
      with Not_found -> ()
    in
    List.iter check_existing_type types
  in
  let check ({loc;v=id}, (params, def)) =
    let same_name {v=id1} {v=id2} = Id.equal id1 id2 in
    let () = match List.duplicates same_name params with
    | [] -> ()
    | {loc;v=id} :: _ ->
      user_err ?loc (str "The type parameter " ++ Id.print id ++
        str " occurs several times")
    in
    match def with
    | CTydDef _ ->
      if isrec then
        user_err ?loc (str "The type abbreviation " ++ Id.print id ++
          str " cannot be recursive")
    | CTydAlg cs ->
      let same_name (id1, _) (id2, _) = Id.equal id1 id2 in
      let () = match List.duplicates same_name cs with
      | [] -> ()
      | (id, _) :: _ ->
        user_err (str "Multiple definitions of the constructor " ++ Id.print id)
      in
      let () =
        let check_uppercase_ident (id,_) =
          if not (Tac2env.is_constructor_id id)
          then user_err (str "Constructor name should start with an uppercase letter " ++ Id.print id)
        in
        List.iter check_uppercase_ident cs
      in
      let () =
        let check_existing_ctor (id, _) =
          let (_, kn) = Lib.make_foname id in
          try let _ = Tac2env.interp_constructor kn in
            user_err (str "Constructor already defined in this module " ++ Id.print id)
          with Not_found -> ()
        in
        List.iter check_existing_ctor cs
      in
      ()
    | CTydRec ps ->
      let same_name (id1, _, _) (id2, _, _) = Id.equal id1 id2 in
      let () = match List.duplicates same_name ps with
      | [] -> ()
      | (id, _, _) :: _ ->
        user_err (str "Multiple definitions of the projection " ++ Id.print id)
      in
      ()
    | CTydOpn ->
      if isrec then
        user_err ?loc (str "The open type declaration " ++ Id.print id ++
          str " cannot be recursive")
  in
  let () = List.iter check types in
  let self =
    if isrec then
      let fold accu ({v=id}, (params, _)) =
        Id.Map.add id (Lib.make_kn id, List.length params) accu
      in
      List.fold_left fold Id.Map.empty types
    else Id.Map.empty
  in
  let map ({v=id}, def) =
    let typdef = {
      typdef_local = local;
      typdef_expr = intern_typedef self def;
    } in
    (id, typdef)
  in
  let types = List.map map types in
  let iter (id, def) = ignore (Lib.add_leaf id (inTypDef def)) in
  List.iter iter types

let register_primitive ?deprecation ?(local = false) {loc;v=id} t ml =
  let t = intern_open_type t in
  let rec count_arrow = function
  | GTypArrow (_, t) -> 1 + count_arrow t
  | _ -> 0
  in
  let arrows = count_arrow (snd t) in
  let () = if Int.equal arrows 0 then
    user_err ?loc (str "External tactic must have at least one argument") in
  let () =
    try let _ = Tac2env.interp_primitive ml in () with Not_found ->
      user_err ?loc (str "Unregistered primitive " ++
        quote (str ml.mltac_plugin) ++ spc () ++ quote (str ml.mltac_tactic))
  in
  let init i = Id.of_string (Printf.sprintf "x%i" i) in
  let names = List.init arrows init in
  let bnd = List.map (fun id -> Name id) names in
  let arg = List.map (fun id -> GTacVar id) names in
  let e = GTacFun (bnd, GTacPrm (ml, arg)) in
  let def = {
    tacdef_local = local;
    tacdef_mutable = false;
    tacdef_expr = e;
    tacdef_type = t;
    tacdef_deprecation = deprecation;
  } in
  ignore (Lib.add_leaf id (inTacDef def))

let register_open ?(local = false) qid (params, def) =
  let kn =
    try Tac2env.locate_type qid
    with Not_found ->
      user_err ?loc:qid.CAst.loc (str "Unbound type " ++ pr_qualid qid)
  in
  let (tparams, t) = Tac2env.interp_type kn in
  let () = match t with
  | GTydOpn -> ()
  | GTydAlg _ | GTydRec _ | GTydDef _ ->
    user_err ?loc:qid.CAst.loc (str "Type " ++ pr_qualid qid ++ str " is not an open type")
  in
  let () =
    if not (Int.equal (List.length params) tparams) then
      Tac2intern.error_nparams_mismatch ?loc:qid.CAst.loc (List.length params) tparams
  in
  match def with
  | CTydOpn -> ()
  | CTydAlg def ->
    let () =
      let same_name (id1, _) (id2, _) = Id.equal id1 id2 in
      let () = match List.duplicates same_name def with
        | [] -> ()
        | (id, _) :: _ ->
          user_err (str "Multiple definitions of the constructor " ++ Id.print id)
      in
      let check_existing_ctor (id, _) =
          let (_, kn) = Lib.make_foname id in
          try let _ = Tac2env.interp_constructor kn in
            user_err (str "Constructor already defined in this module " ++ Id.print id)
          with Not_found -> ()
      in
      let () = List.iter check_existing_ctor def in
      ()
    in
    let intern_type t =
      let tpe = CTydDef (Some t) in
      let (_, ans) = intern_typedef Id.Map.empty (params, tpe) in
      match ans with
      | GTydDef (Some t) -> t
      | _ -> assert false
    in
    let map (id, tpe) =
      if not (Tac2env.is_constructor_id id)
      then user_err (str "Constructor name should start with an uppercase letter " ++ Id.print id) ;
      let tpe = List.map intern_type tpe in
      { edata_name = id; edata_args = tpe }
    in
    let def = List.map map def in
    let def = {
      typext_local = local;
      typext_type = kn;
      typext_prms = tparams;
      typext_expr = def;
    } in
    Lib.add_anonymous_leaf (inTypExt def)
  | CTydRec _ | CTydDef _ ->
    user_err ?loc:qid.CAst.loc (str "Extensions only accept inductive constructors")

let register_type ?local isrec types = match types with
| [qid, true, def] ->
  let () = if isrec then user_err ?loc:qid.CAst.loc (str "Extensions cannot be recursive") in
  register_open ?local qid def
| _ ->
  let map (qid, redef, def) =
    let () = if redef then
      user_err ?loc:qid.loc (str "Types can only be extended one by one")
    in
    (qualid_to_ident qid, def)
  in
  let types = List.map map types in
  register_typedef ?local isrec types

(** Parsing *)

type 'a token =
| TacTerm of string
| TacNonTerm of Name.t * 'a

type scope_rule =
| ScopeRule : (raw_tacexpr, _, 'a) Pcoq.Symbol.t * ('a -> raw_tacexpr) -> scope_rule

type scope_interpretation = sexpr list -> scope_rule

let scope_table : scope_interpretation Id.Map.t ref = ref Id.Map.empty

let register_scope id s =
  scope_table := Id.Map.add id s !scope_table

module ParseToken =
struct

let loc_of_token = function
| SexprStr {loc} -> loc
| SexprInt {loc} -> loc
| SexprRec (loc, _, _) -> Some loc

let parse_scope = function
| SexprRec (_, {loc;v=Some id}, toks) ->
  if Id.Map.mem id !scope_table then
    Id.Map.find id !scope_table toks
  else
    CErrors.user_err ?loc (str "Unknown scope" ++ spc () ++ Names.Id.print id)
| SexprStr {v=str} ->
  let v_unit = CAst.make @@ CTacCst (AbsKn (Tuple 0)) in
  ScopeRule (Pcoq.Symbol.token (Tok.PIDENT (Some str)), (fun _ -> v_unit))
| tok ->
  let loc = loc_of_token tok in
  CErrors.user_err ?loc (str "Invalid parsing token")

let parse_token = function
| SexprStr {v=s} -> TacTerm s
| SexprRec (_, {v=na}, [tok]) ->
  let na = match na with None -> Anonymous | Some id -> Name id in
  let scope = parse_scope tok in
  TacNonTerm (na, scope)
| tok ->
  let loc = loc_of_token tok in
  CErrors.user_err ?loc (str "Invalid parsing token")

let rec print_scope = function
| SexprStr s -> str s.CAst.v
| SexprInt i -> int i.CAst.v
| SexprRec (_, {v=na}, []) -> Option.cata Id.print (str "_") na
| SexprRec (_, {v=na}, e) ->
  Option.cata Id.print (str "_") na ++ str "(" ++ pr_sequence print_scope e ++ str ")"

let print_token = function
| SexprStr {v=s} -> quote (str s)
| SexprRec (_, {v=na}, [tok]) -> print_scope tok
| _ -> assert false

end

let parse_scope = ParseToken.parse_scope

type synext = {
  synext_tok : sexpr list;
  synext_exp : raw_tacexpr;
  synext_lev : int;
  synext_loc : bool;
  synext_depr : Deprecation.t option;
}

type krule =
| KRule :
  (raw_tacexpr, _, 'act, Loc.t -> raw_tacexpr) Pcoq.Rule.t *
  ((Loc.t -> (Name.t * raw_tacexpr) list -> raw_tacexpr) -> 'act) -> krule

let rec get_rule (tok : scope_rule token list) : krule = match tok with
| [] -> KRule (Pcoq.Rule.stop, fun k loc -> k loc [])
| TacNonTerm (na, ScopeRule (scope, inj)) :: tok ->
  let KRule (rule, act) = get_rule tok in
  let rule = Pcoq.Rule.next rule scope in
  let act k e = act (fun loc acc -> k loc ((na, inj e) :: acc)) in
  KRule (rule, act)
| TacTerm t :: tok ->
  let KRule (rule, act) = get_rule tok in
  let rule = Pcoq.(Rule.next rule (Symbol.token (CLexer.terminal t))) in
  let act k _ = act k in
  KRule (rule, act)

let deprecated_ltac2_notation =
  Deprecation.create_warning
    ~object_name:"Ltac2 notation"
    ~warning_name:"deprecated-ltac2-notation"
    (fun (toks : sexpr list) -> pr_sequence ParseToken.print_token toks)

(* This is a hack to preserve the level 4 entry which is initially empty. The
   grammar engine has the great idea to silently delete empty levels on rule
   removal, so we have to work around this using the Pcoq API.
   FIXME: we should really keep those levels around instead. *)
let get_reinit = function
| 4 -> Some (Gramlib.Gramext.LeftA, Gramlib.Gramext.After "5")
| _ -> None

let perform_notation syn st =
  let tok = List.rev_map ParseToken.parse_token syn.synext_tok in
  let KRule (rule, act) = get_rule tok in
  let mk loc args =
    let () = match syn.synext_depr with
    | None -> ()
    | Some depr -> deprecated_ltac2_notation ~loc (syn.synext_tok, depr)
    in
    let map (na, e) =
      ((CAst.make ?loc:e.loc @@ CPatVar na), e)
    in
    let bnd = List.map map args in
    CAst.make ~loc @@ CTacLet (false, bnd, syn.synext_exp)
  in
  let rule = Pcoq.Production.make rule (act mk) in
  let pos = Some (Gramlib.Gramext.Level (string_of_int syn.synext_lev)) in
  let rule = {Pcoq.pos; data = [(None, None, [rule])] } in
  match get_reinit syn.synext_lev with
  | None ->
    ([Pcoq.ExtendRule (Pltac.ltac2_expr, rule)], st)
  | Some reinit ->
    ([Pcoq.ExtendRuleReinit (Pltac.ltac2_expr, reinit, rule)], st)

let ltac2_notation =
  Pcoq.create_grammar_command "ltac2-notation" perform_notation

let cache_synext (_, syn) =
  Pcoq.extend_grammar_command ltac2_notation syn

let open_synext i (_, syn) =
  if Int.equal i 1 then Pcoq.extend_grammar_command ltac2_notation syn

let subst_synext (subst, syn) =
  let e = Tac2intern.subst_rawexpr subst syn.synext_exp in
  if e == syn.synext_exp then syn else { syn with synext_exp = e }

let classify_synext o =
  if o.synext_loc then Dispose else Substitute o

let inTac2Notation : synext -> obj =
  declare_object {(default_object "TAC2-NOTATION") with
     cache_function  = cache_synext;
     open_function   = simple_open open_synext;
     subst_function = subst_synext;
     classify_function = classify_synext}

type abbreviation = {
  abbr_body : raw_tacexpr;
  abbr_depr : Deprecation.t option;
}

let perform_abbreviation visibility ((sp, kn), abbr) =
  let () = Tac2env.push_ltac visibility sp (TacAlias kn) in
  Tac2env.define_alias ?deprecation:abbr.abbr_depr kn abbr.abbr_body

let load_abbreviation i obj = perform_abbreviation (Until i) obj
let open_abbreviation i obj = perform_abbreviation (Exactly i) obj

let cache_abbreviation ((sp, kn), abbr) =
  let () = Tac2env.push_ltac (Until 1) sp (TacAlias kn) in
  Tac2env.define_alias ?deprecation:abbr.abbr_depr kn abbr.abbr_body

let subst_abbreviation (subst, abbr) =
  let body' = subst_rawexpr subst abbr.abbr_body in
  if body' == abbr.abbr_body then abbr
  else { abbr_body = body'; abbr_depr = abbr.abbr_depr }

let classify_abbreviation o = Substitute o

let inTac2Abbreviation : abbreviation -> obj =
  declare_object {(default_object "TAC2-ABBREVIATION") with
     cache_function  = cache_abbreviation;
     load_function   = load_abbreviation;
     open_function   = simple_open open_abbreviation;
     subst_function = subst_abbreviation;
     classify_function = classify_abbreviation}

let register_notation ?deprecation ?(local = false) tkn lev body = match tkn, lev with
| [SexprRec (_, {loc;v=Some id}, [])], None ->
  (* Tactic abbreviation *)
  let () = check_lowercase CAst.(make ?loc id) in
  let body = Tac2intern.globalize Id.Set.empty body in
  let abbr = { abbr_body = body; abbr_depr = deprecation } in
  ignore (Lib.add_leaf id (inTac2Abbreviation abbr))
| _ ->
  (* Check that the tokens make sense *)
  let entries = List.map ParseToken.parse_token tkn in
  let fold accu tok = match tok with
  | TacTerm _ -> accu
  | TacNonTerm (Name id, _) -> Id.Set.add id accu
  | TacNonTerm (Anonymous, _) -> accu
  in
  let ids = List.fold_left fold Id.Set.empty entries in
  (* Globalize so that names are absolute *)
  let body = Tac2intern.globalize ids body in
  let lev = match lev with
  | Some n ->
    let () =
      if n < 0 || n > 6 then
        user_err (str "Notation levels must range between 0 and 6")
    in
    n
  | None -> 5
  in
  let ext = {
    synext_tok = tkn;
    synext_exp = body;
    synext_lev = lev;
    synext_loc = local;
    synext_depr = deprecation;
  } in
  Lib.add_anonymous_leaf (inTac2Notation ext)

type redefinition = {
  redef_kn : ltac_constant;
  redef_body : glb_tacexpr;
  redef_old : Id.t option;
}

let perform_redefinition (_, redef) =
  let kn = redef.redef_kn in
  let data = Tac2env.interp_global kn in
  let body = match redef.redef_old with
  | None -> redef.redef_body
  | Some id ->
    (* Rebind the old value with a let-binding *)
    GTacLet (false, [Name id, data.Tac2env.gdata_expr], redef.redef_body)
  in
  let data = { data with Tac2env.gdata_expr = body } in
  Tac2env.define_global kn data

let subst_redefinition (subst, redef) =
  let kn = Mod_subst.subst_kn subst redef.redef_kn in
  let body = Tac2intern.subst_expr subst redef.redef_body in
  if kn == redef.redef_kn && body == redef.redef_body then redef
  else { redef_kn = kn; redef_body = body; redef_old = redef.redef_old }

let classify_redefinition o = Substitute o

let inTac2Redefinition : redefinition -> obj =
  declare_object {(default_object "TAC2-REDEFINITION") with
     cache_function  = perform_redefinition;
     open_function   = simple_open (fun _ -> perform_redefinition);
     subst_function = subst_redefinition;
     classify_function = classify_redefinition }

let register_redefinition ?(local = false) qid old e =
  let kn =
    try Tac2env.locate_ltac qid
    with Not_found -> user_err ?loc:qid.CAst.loc (str "Unknown tactic " ++ pr_qualid qid)
  in
  let kn = match kn with
  | TacConstant kn -> kn
  | TacAlias _ ->
    user_err ?loc:qid.CAst.loc (str "Cannot redefine syntactic abbreviations")
  in
  let data = Tac2env.interp_global kn in
  let () =
    if not (data.Tac2env.gdata_mutable) then
      user_err ?loc:qid.CAst.loc (str "The tactic " ++ pr_qualid qid ++ str " is not declared as mutable")
  in
  let ctx = match old with
  | None -> []
  | Some { CAst.v = id } -> [id, data.Tac2env.gdata_type]
  in
  let (e, t) = intern ~strict:true ctx e in
  let () =
    if not (is_value e) then
      user_err ?loc:qid.CAst.loc (str "Tactic definition must be a syntactical value")
  in
  let () =
    if not (Tac2intern.check_subtype t data.Tac2env.gdata_type) then
      let name = int_name () in
      user_err ?loc:qid.CAst.loc (str "Type " ++ pr_glbtype name (snd t) ++
        str " is not a subtype of " ++ pr_glbtype name (snd data.Tac2env.gdata_type))
  in
  let old = Option.map (fun { CAst.v = id } -> id) old in
  let def = {
    redef_kn = kn;
    redef_body = e;
    redef_old = old;
  } in
  Lib.add_anonymous_leaf (inTac2Redefinition def)

let perform_eval ~pstate e =
  let env = Global.env () in
  let (e, ty) = Tac2intern.intern ~strict:false [] e in
  let v = Tac2interp.interp Tac2interp.empty_environment e in
  let selector, proof =
    match pstate with
    | None ->
      let sigma = Evd.from_env env in
      let name, poly = Id.of_string "ltac2", false in
      Goal_select.SelectAll, Proof.start ~name ~poly sigma []
    | Some pstate ->
      Goal_select.get_default_goal_selector (),
      Declare.Proof.get pstate
  in
  let nosuchgoal =
    let info = Exninfo.reify () in
    Proofview.tclZERO ~info (Proof.SuggestNoSuchGoals (1,proof))
  in
  let v = Goal_select.tclSELECT ~nosuchgoal selector v in
  let (proof, _, ans) = Proof.run_tactic (Global.env ()) v proof in
  let { Proof.sigma } = Proof.data proof in
  let name = int_name () in
  Feedback.msg_notice (str "- : " ++ pr_glbtype name (snd ty)
    ++ spc () ++  str "=" ++ spc () ++
    Tac2print.pr_valexpr env sigma ans (snd ty))

(** Toplevel entries *)

let unsupported_deprecation = function
| None -> ()
| Some _ ->
  Attributes.unsupported_attributes ["deprecated", Attributes.VernacFlagEmpty]

let register_struct ?deprecation ?local str = match str with
| StrVal (mut, isrec, e) -> register_ltac ?deprecation ?local ~mut isrec e
| StrTyp (isrec, t) ->
  let () = unsupported_deprecation deprecation in (* TODO *)
  register_type ?local isrec t
| StrPrm (id, t, ml) -> register_primitive ?deprecation ?local id t ml
| StrSyn (tok, lev, e) -> register_notation ?deprecation ?local tok lev e
| StrMut (qid, old, e) ->
  let () = unsupported_deprecation deprecation in (* TODO: what does that mean? *)
  register_redefinition ?local qid old e

(** Toplevel exception *)

let _ = Goptions.declare_bool_option {
  Goptions.optdepr = false;
  Goptions.optkey = ["Ltac2"; "Backtrace"];
  Goptions.optread = (fun () -> !Tac2interp.print_ltac2_backtrace);
  Goptions.optwrite = (fun b -> Tac2interp.print_ltac2_backtrace := b);
}

let backtrace : backtrace Exninfo.t = Exninfo.make ()

let pr_frame = function
| FrAnon e -> str "Call {" ++ pr_glbexpr e ++ str "}"
| FrLtac kn ->
  str "Call " ++ Libnames.pr_qualid (Tac2env.shortest_qualid_of_ltac (TacConstant kn))
| FrPrim ml ->
  str "Prim <" ++ str ml.mltac_plugin ++ str ":" ++ str ml.mltac_tactic ++ str ">"
| FrExtn (tag, arg) ->
  let obj = Tac2env.interp_ml_object tag in
  let env = Global.env () in
  let sigma = Evd.from_env env in
  str "Extn " ++ str (Tac2dyn.Arg.repr tag) ++ str ":" ++ spc () ++
    obj.Tac2env.ml_print env sigma arg

let () = register_handler begin function
| Tac2interp.LtacError (kn, args) ->
  let t_exn = KerName.make Tac2env.coq_prefix (Label.make "exn") in
  let v = Tac2ffi.of_open (kn, args) in
  let t = GTypRef (Other t_exn, []) in
  let c = Tac2print.pr_valexpr (Global.env ()) Evd.empty v t in
  Some (hov 0 (str "Uncaught Ltac2 exception:" ++ spc () ++ hov 0 c))
| _ -> None
end

let () = CErrors.register_additional_error_info begin fun info ->
  if !Tac2interp.print_ltac2_backtrace then
    let bt = Exninfo.get info backtrace in
    let bt = match bt with
    | Some bt -> bt
    | None -> []
    in
    let bt =
      str "Backtrace:" ++ fnl () ++ prlist_with_sep fnl pr_frame bt ++ fnl ()
    in
    Some (Loc.tag bt)
  else None
end

(** Printing *)

let print_ltac qid =
  if Tac2env.is_constructor qid then
    let kn =
      try Tac2env.locate_constructor qid
      with Not_found -> user_err ?loc:qid.CAst.loc (str "Unknown constructor " ++ pr_qualid qid)
    in
    let _ = Tac2env.interp_constructor kn in
    Feedback.msg_notice (hov 2 (str "Constructor" ++ spc () ++ str ":" ++ spc () ++ pr_qualid qid))
  else
    let kn =
      try Tac2env.locate_ltac qid
      with Not_found -> user_err ?loc:qid.CAst.loc (str "Unknown tactic " ++ pr_qualid qid)
    in
    match kn with
    | TacConstant kn ->
      let data = Tac2env.interp_global kn in
      let e = data.Tac2env.gdata_expr in
      let (_, t) = data.Tac2env.gdata_type in
      let name = int_name () in
      Feedback.msg_notice (
        hov 0 (
          hov 2 (pr_qualid qid ++ spc () ++ str ":" ++ spc () ++ pr_glbtype name t) ++ fnl () ++
          hov 2 (pr_qualid qid ++ spc () ++ str ":=" ++ spc () ++ pr_glbexpr e)
        )
      )
    | TacAlias kn ->
      Feedback.msg_notice (str "Alias to ...")

(** Calling tactics *)

let ltac2_interp e =
  let loc = e.loc in
  let (e, t) = intern ~strict:false [] e in
  let () = check_unit ?loc t in
  let tac = Tac2interp.interp Tac2interp.empty_environment e in
  Proofview.tclIGNORE tac

let ComTactic.Interpreter ltac2_interp = ComTactic.register_tactic_interpreter "ltac2" ltac2_interp

let call ~pstate ~with_end_tac tac =
  ComTactic.solve ~pstate ~with_end_tac
    (Goal_select.get_default_goal_selector())
    ~info:None (ltac2_interp tac)

(** Primitive algebraic types than can't be defined Coq-side *)

let register_prim_alg name params def =
  let id = Id.of_string name in
  let def = List.map (fun (cstr, tpe) -> (Id.of_string_soft cstr, tpe)) def in
  let getn (const, nonconst) (c, args) = match args with
  | [] -> (succ const, nonconst)
  | _ :: _ -> (const, succ nonconst)
  in
  let nconst, nnonconst = List.fold_left getn (0, 0) def in
  let alg = {
    galg_constructors = def;
    galg_nconst = nconst;
    galg_nnonconst = nnonconst;
  } in
  let def = (params, GTydAlg alg) in
  let def = { typdef_local = false; typdef_expr = def } in
  ignore (Lib.add_leaf id (inTypDef def))

let coq_def n = KerName.make Tac2env.coq_prefix (Label.make n)

let def_unit = {
  typdef_local = false;
  typdef_expr = 0, GTydDef (Some (GTypRef (Tuple 0, [])));
}

let t_list = coq_def "list"

let (f_register_constr_quotations, register_constr_quotations) = Hook.make ()

let cache_ltac2_init (_, ()) =
  Hook.get f_register_constr_quotations ()

let load_ltac2_init _ (_, ()) =
  Hook.get f_register_constr_quotations ()

let open_ltac2_init _ (_, ()) =
  Goptions.set_string_option_value_gen ["Default"; "Proof"; "Mode"] "Ltac2"

(** Dummy object that register global rules when Require is called *)
let inTac2Init : unit -> obj =
  declare_object {(default_object "TAC2-INIT") with
    cache_function = cache_ltac2_init;
    load_function = load_ltac2_init;
    open_function = simple_open open_ltac2_init;
  }

let _ = Mltop.declare_cache_obj begin fun () ->
  ignore (Lib.add_leaf (Id.of_string "unit") (inTypDef def_unit));
  register_prim_alg "list" 1 [
    ("[]", []);
    ("::", [GTypVar 0; GTypRef (Other t_list, [GTypVar 0])]);
  ];
  Lib.add_anonymous_leaf (inTac2Init ());
end "ltac2_plugin"