X-Git-Url: http://matita.cs.unibo.it/gitweb/?p=helm.git;a=blobdiff_plain;f=helm%2Focaml%2Fcontent_pres%2FtermContentPres.ml;fp=helm%2Focaml%2Fcontent_pres%2FtermContentPres.ml;h=4c8bbc7d4e4af42ff8defbee358438dd0f139cf5;hp=0000000000000000000000000000000000000000;hb=792b5d29ebae8f917043d9dd226692919b5d6ca1;hpb=a14a8c7637fd0b95e9d4deccb20c6abc98e8f953

diff --git a/helm/ocaml/content_pres/termContentPres.ml b/helm/ocaml/content_pres/termContentPres.ml
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+(* Copyright (C) 2004-2005, HELM Team.
+ * 
+ * This file is part of HELM, an Hypertextual, Electronic
+ * Library of Mathematics, developed at the Computer Science
+ * Department, University of Bologna, Italy.
+ * 
+ * HELM is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ * 
+ * HELM is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HELM; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA  02111-1307, USA.
+ * 
+ * For details, see the HELM World-Wide-Web page,
+ * http://helm.cs.unibo.it/
+ *)
+
+(* $Id$ *)
+
+open Printf
+
+module Ast = CicNotationPt
+module Env = CicNotationEnv
+
+let debug = false
+let debug_print s = if debug then prerr_endline (Lazy.force s) else ()
+
+type pattern_id = int
+type pretty_printer_id = pattern_id
+
+let resolve_binder = function
+  | `Lambda -> "\\lambda"
+  | `Pi -> "\\Pi"
+  | `Forall -> "\\forall"
+  | `Exists -> "\\exists"
+
+let add_level_info prec assoc t = Ast.AttributedTerm (`Level (prec, assoc), t)
+let add_pos_info pos t = Ast.AttributedTerm (`ChildPos pos, t)
+let left_pos = add_pos_info `Left
+let right_pos = add_pos_info `Right
+let inner_pos = add_pos_info `Inner
+
+let rec top_pos t = add_level_info ~-1 Gramext.NonA (inner_pos t)
+(*   function
+  | Ast.AttributedTerm (`Level _, t) ->
+      add_level_info ~-1 Gramext.NonA (inner_pos t)
+  | Ast.AttributedTerm (attr, t) -> Ast.AttributedTerm (attr, top_pos t)
+  | t -> add_level_info ~-1 Gramext.NonA (inner_pos t) *)
+
+let rec remove_level_info =
+  function
+  | Ast.AttributedTerm (`Level _, t) -> remove_level_info t
+  | Ast.AttributedTerm (a, t) -> Ast.AttributedTerm (a, remove_level_info t)
+  | t -> t
+
+let add_xml_attrs attrs t =
+  if attrs = [] then t else Ast.AttributedTerm (`XmlAttrs attrs, t)
+
+let add_keyword_attrs =
+  add_xml_attrs (RenderingAttrs.keyword_attributes `MathML)
+
+let box kind spacing indent content =
+  Ast.Layout (Ast.Box ((kind, spacing, indent), content))
+
+let hbox = box Ast.H
+let vbox = box Ast.V
+let hvbox = box Ast.HV
+let hovbox = box Ast.HOV
+let break = Ast.Layout Ast.Break
+let builtin_symbol s = Ast.Literal (`Symbol s)
+let keyword k = add_keyword_attrs (Ast.Literal (`Keyword k))
+
+let number s =
+  add_xml_attrs (RenderingAttrs.number_attributes `MathML)
+    (Ast.Literal (`Number s))
+
+let ident i =
+  add_xml_attrs (RenderingAttrs.ident_attributes `MathML) (Ast.Ident (i, None))
+
+let ident_w_href href i =
+  match href with
+  | None -> ident i
+  | Some href ->
+      let href = UriManager.string_of_uri href in
+      add_xml_attrs [Some "xlink", "href", href] (ident i)
+
+let binder_symbol s =
+  add_xml_attrs (RenderingAttrs.builtin_symbol_attributes `MathML)
+    (builtin_symbol s)
+
+let string_of_sort_kind = function
+  | `Prop -> "Prop"
+  | `Set -> "Set"
+  | `CProp -> "CProp"
+  | `Type _ -> "Type"
+
+let pp_ast0 t k =
+  let rec aux =
+    function
+    | Ast.Appl ts ->
+        let rec aux_args pos =
+          function
+          | [] -> []
+          | [ last ] ->
+              let last = k last in
+              if pos = `Left then [ left_pos last ] else [ right_pos last ]
+          | hd :: tl ->
+              (add_pos_info pos (k hd)) :: aux_args `Inner tl
+        in
+        add_level_info Ast.apply_prec Ast.apply_assoc
+          (hovbox true true (CicNotationUtil.dress break (aux_args `Left ts)))
+    | Ast.Binder (binder_kind, (id, ty), body) ->
+        add_level_info Ast.binder_prec Ast.binder_assoc
+          (hvbox false true
+            [ binder_symbol (resolve_binder binder_kind);
+              k id; builtin_symbol ":"; aux_ty ty; break;
+              builtin_symbol "."; right_pos (k body) ])
+    | Ast.Case (what, indty_opt, outty_opt, patterns) ->
+        let outty_box =
+          match outty_opt with
+          | None -> []
+          | Some outty ->
+              [ keyword "return"; break; remove_level_info (k outty)]
+        in
+        let indty_box =
+          match indty_opt with
+          | None -> []
+          | Some (indty, href) -> [ keyword "in"; break; ident_w_href href indty ]
+        in
+        let match_box =
+          hvbox false false [
+           hvbox false true [
+            hvbox false true [ keyword "match"; break; top_pos (k what) ];
+            break;
+            hvbox false true indty_box;
+            break;
+            hvbox false true outty_box
+           ];
+           break;
+           keyword "with"
+         ]
+        in
+        let mk_case_pattern (head, href, vars) =
+          hbox true false (ident_w_href href head :: List.map aux_var vars)
+        in
+        let patterns' =
+          List.map
+            (fun (lhs, rhs) ->
+              remove_level_info
+                (hvbox false true [
+                  hbox false true [
+                    mk_case_pattern lhs; builtin_symbol "\\Rightarrow" ];
+                  break; top_pos (k rhs) ]))
+            patterns
+        in
+        let patterns'' =
+          let rec aux_patterns = function
+            | [] -> assert false
+            | [ last ] ->
+                [ break; 
+                  hbox false false [
+                    builtin_symbol "|";
+                    last; builtin_symbol "]" ] ]
+            | hd :: tl ->
+                [ break; hbox false false [ builtin_symbol "|"; hd ] ]
+                @ aux_patterns tl
+          in
+          match patterns' with
+          | [] ->
+              [ hbox false false [ builtin_symbol "["; builtin_symbol "]" ] ]
+          | [ one ] ->
+              [ hbox false false [
+                builtin_symbol "["; one; builtin_symbol "]" ] ]
+          | hd :: tl ->
+              hbox false false [ builtin_symbol "["; hd ]
+              :: aux_patterns tl
+        in
+        add_level_info Ast.simple_prec Ast.simple_assoc
+          (hvbox false false [
+            hvbox false false ([match_box]); break;
+            hbox false false [ hvbox false false patterns'' ] ])
+    | Ast.Cast (bo, ty) ->
+        add_level_info Ast.simple_prec Ast.simple_assoc
+          (hvbox false true [
+            builtin_symbol "("; top_pos (k bo); break; builtin_symbol ":";
+            top_pos (k ty); builtin_symbol ")"])
+    | Ast.LetIn (var, s, t) ->
+        add_level_info Ast.let_in_prec Ast.let_in_assoc
+          (hvbox false true [
+            hvbox false true [
+              keyword "let";
+              hvbox false true [
+                aux_var var; builtin_symbol "\\def"; break; top_pos (k s) ];
+              break; keyword "in" ];
+            break;
+            k t ])
+    | Ast.LetRec (rec_kind, funs, where) ->
+        let rec_op =
+          match rec_kind with `Inductive -> "rec" | `CoInductive -> "corec"
+        in
+        let mk_fun (var, body, _) = aux_var var, k body in
+        let mk_funs = List.map mk_fun in
+        let fst_fun, tl_funs =
+          match mk_funs funs with hd :: tl -> hd, tl | [] -> assert false
+        in
+        let fst_row =
+          let (name, body) = fst_fun in
+          hvbox false true [
+            keyword "let"; keyword rec_op; name; builtin_symbol "\\def"; break;
+            top_pos body ]
+        in
+        let tl_rows =
+          List.map
+            (fun (name, body) ->
+              [ break;
+                hvbox false true [
+                  keyword "and"; name; builtin_symbol "\\def"; break; body ] ])
+            tl_funs
+        in
+        add_level_info Ast.let_in_prec Ast.let_in_assoc
+          ((hvbox false false
+            (fst_row :: List.flatten tl_rows
+             @ [ break; keyword "in"; break; k where ])))
+    | Ast.Implicit -> builtin_symbol "?"
+    | Ast.Meta (n, l) ->
+        let local_context l =
+          CicNotationUtil.dress (builtin_symbol ";")
+            (List.map (function None -> builtin_symbol "_" | Some t -> k t) l)
+        in
+        hbox false false
+          ([ builtin_symbol "?"; number (string_of_int n) ]
+            @ (if l <> [] then local_context l else []))
+    | Ast.Sort sort -> aux_sort sort
+    | Ast.Num _
+    | Ast.Symbol _
+    | Ast.Ident (_, None) | Ast.Ident (_, Some [])
+    | Ast.Uri (_, None) | Ast.Uri (_, Some [])
+    | Ast.Literal _
+    | Ast.UserInput as leaf -> leaf
+    | t -> CicNotationUtil.visit_ast ~special_k k t
+  and aux_sort sort_kind =
+    add_xml_attrs (RenderingAttrs.keyword_attributes `MathML)
+      (Ast.Ident (string_of_sort_kind sort_kind, None))
+  and aux_ty = function
+    | None -> builtin_symbol "?"
+    | Some ty -> k ty
+  and aux_var = function
+    | name, Some ty ->
+        hvbox false true [
+          builtin_symbol "("; name; builtin_symbol ":"; break; k ty;
+          builtin_symbol ")" ]
+    | name, None -> name
+  and special_k = function
+    | Ast.AttributedTerm (attrs, t) -> Ast.AttributedTerm (attrs, k t)
+    | t ->
+        prerr_endline ("unexpected special: " ^ CicNotationPp.pp_term t);
+        assert false
+  in
+  aux t
+
+  (* persistent state *)
+
+let level1_patterns21 = Hashtbl.create 211
+
+let compiled21 = ref None
+
+let pattern21_matrix = ref []
+
+let get_compiled21 () =
+  match !compiled21 with
+  | None -> assert false
+  | Some f -> Lazy.force f
+
+let set_compiled21 f = compiled21 := Some f
+
+let add_idrefs =
+  List.fold_right (fun idref t -> Ast.AttributedTerm (`IdRef idref, t))
+
+let instantiate21 idrefs env l1 =
+  let rec subst_singleton pos env =
+    function
+      Ast.AttributedTerm (attr, t) ->
+        Ast.AttributedTerm (attr, subst_singleton pos env t)
+    | t -> CicNotationUtil.group (subst pos env t)
+  and subst pos env = function
+    | Ast.AttributedTerm (attr, t) ->
+(*         prerr_endline ("loosing attribute " ^ CicNotationPp.pp_attribute attr); *)
+        subst pos env t
+    | Ast.Variable var ->
+        let name, expected_ty = CicNotationEnv.declaration_of_var var in
+        let ty, value =
+          try
+            List.assoc name env
+          with Not_found ->
+            prerr_endline ("name " ^ name ^ " not found in environment");
+            assert false
+        in
+        assert (CicNotationEnv.well_typed ty value); (* INVARIANT *)
+        (* following assertion should be a conditional that makes this
+         * instantiation fail *)
+        assert (CicNotationEnv.well_typed expected_ty value);
+        [ add_pos_info pos (CicNotationEnv.term_of_value value) ]
+    | Ast.Magic m -> subst_magic pos env m
+    | Ast.Literal l as t ->
+        let t = add_idrefs idrefs t in
+        (match l with
+        | `Keyword k -> [ add_keyword_attrs t ]
+        | _ -> [ t ])
+    | Ast.Layout l -> [ Ast.Layout (subst_layout pos env l) ]
+    | t -> [ CicNotationUtil.visit_ast (subst_singleton pos env) t ]
+  and subst_magic pos env = function
+    | Ast.List0 (p, sep_opt)
+    | Ast.List1 (p, sep_opt) ->
+        let rec_decls = CicNotationEnv.declarations_of_term p in
+        let rec_values =
+          List.map (fun (n, _) -> CicNotationEnv.lookup_list env n) rec_decls
+        in
+        let values = CicNotationUtil.ncombine rec_values in
+        let sep =
+          match sep_opt with
+            | None -> []
+            | Some l -> [ Ast.Literal l ]
+	in
+        let rec instantiate_list acc = function
+          | [] -> List.rev acc
+	  | value_set :: [] ->
+	      let env = CicNotationEnv.combine rec_decls value_set in
+              instantiate_list (CicNotationUtil.group (subst pos env p) :: acc)
+                []
+          | value_set :: tl ->
+              let env = CicNotationEnv.combine rec_decls value_set in
+              let terms = subst pos env p in
+              instantiate_list (CicNotationUtil.group (terms @ sep) :: acc) tl
+        in
+        instantiate_list [] values
+    | Ast.Opt p ->
+        let opt_decls = CicNotationEnv.declarations_of_term p in
+        let env =
+          let rec build_env = function
+            | [] -> []
+            | (name, ty) :: tl ->
+                  (* assumption: if one of the value is None then all are *)
+                (match CicNotationEnv.lookup_opt env name with
+                | None -> raise Exit
+                | Some v -> (name, (ty, v)) :: build_env tl)
+          in
+          try build_env opt_decls with Exit -> []
+        in
+	  begin
+	    match env with
+	      | [] -> []
+	      | _ -> subst pos env p
+	  end
+    | _ -> assert false (* impossible *)
+  and subst_layout pos env = function
+    | Ast.Box (kind, tl) ->
+        let tl' = subst_children pos env tl in
+        Ast.Box (kind, List.concat tl')
+    | l -> CicNotationUtil.visit_layout (subst_singleton pos env) l
+  and subst_children pos env =
+    function
+    | [] -> []
+    | [ child ] ->
+        let pos' =
+          match pos with
+          | `Inner -> `Right
+          | `Left -> `Left
+(*           | `None -> assert false *)
+          | `Right -> `Right
+        in
+        [ subst pos' env child ]
+    | hd :: tl ->
+        let pos' =
+          match pos with
+          | `Inner -> `Inner
+          | `Left -> `Inner
+(*           | `None -> assert false *)
+          | `Right -> `Right
+        in
+        (subst pos env hd) :: subst_children pos' env tl
+  in
+    subst_singleton `Left env l1
+
+let rec pp_ast1 term = 
+  let rec pp_value = function
+    | CicNotationEnv.NumValue _ as v -> v
+    | CicNotationEnv.StringValue _ as v -> v
+(*     | CicNotationEnv.TermValue t when t == term -> CicNotationEnv.TermValue (pp_ast0 t pp_ast1) *)
+    | CicNotationEnv.TermValue t -> CicNotationEnv.TermValue (pp_ast1 t)
+    | CicNotationEnv.OptValue None as v -> v
+    | CicNotationEnv.OptValue (Some v) -> 
+        CicNotationEnv.OptValue (Some (pp_value v))
+    | CicNotationEnv.ListValue vl ->
+        CicNotationEnv.ListValue (List.map pp_value vl)
+  in
+  let ast_env_of_env env =
+    List.map (fun (var, (ty, value)) -> (var, (ty, pp_value value))) env
+  in
+(* prerr_endline ("pattern matching from 2 to 1 on term " ^ CicNotationPp.pp_term term); *)
+  match term with
+  | Ast.AttributedTerm (attrs, term') ->
+      Ast.AttributedTerm (attrs, pp_ast1 term')
+  | _ ->
+      (match (get_compiled21 ()) term with
+      | None -> pp_ast0 term pp_ast1
+      | Some (env, ctors, pid) ->
+          let idrefs =
+            List.flatten (List.map CicNotationUtil.get_idrefs ctors)
+          in
+          let l1 =
+            try
+              Hashtbl.find level1_patterns21 pid
+            with Not_found -> assert false
+          in
+          instantiate21 idrefs (ast_env_of_env env) l1)
+
+let load_patterns21 t =
+  set_compiled21 (lazy (Content2presMatcher.Matcher21.compiler t))
+
+let pp_ast ast =
+  debug_print (lazy "pp_ast <-");
+  let ast' = pp_ast1 ast in
+  debug_print (lazy ("pp_ast -> " ^ CicNotationPp.pp_term ast'));
+  ast'
+
+exception Pretty_printer_not_found
+
+let fill_pos_info l1_pattern = l1_pattern
+(*   let rec aux toplevel pos =
+    function
+    | Ast.Layout l ->
+        (match l 
+
+    | Ast.Magic m ->
+        Ast.Box (
+    | Ast.Variable _ as t -> add_pos_info pos t
+    | t -> t
+  in
+  aux true l1_pattern *)
+
+let fresh_id =
+  let counter = ref ~-1 in
+  fun () ->
+    incr counter;
+    !counter
+
+let add_pretty_printer ~precedence ~associativity l2 l1 =
+  let id = fresh_id () in
+  let l1' = add_level_info precedence associativity (fill_pos_info l1) in
+  let l2' = CicNotationUtil.strip_attributes l2 in
+  Hashtbl.add level1_patterns21 id l1';
+  pattern21_matrix := (l2', id) :: !pattern21_matrix;
+  load_patterns21 !pattern21_matrix;
+  id
+
+let remove_pretty_printer id =
+  (try
+    Hashtbl.remove level1_patterns21 id;
+  with Not_found -> raise Pretty_printer_not_found);
+  pattern21_matrix := List.filter (fun (_, id') -> id <> id') !pattern21_matrix;
+  load_patterns21 !pattern21_matrix
+
+  (* presentation -> content *)
+
+let unopt_names names env =
+  let rec aux acc = function
+    | (name, (ty, v)) :: tl when List.mem name names ->
+        (match ty, v with
+        | Env.OptType ty, Env.OptValue (Some v) ->
+            aux ((name, (ty, v)) :: acc) tl
+        | _ -> assert false)
+    | hd :: tl -> aux (hd :: acc) tl
+    | [] -> acc
+  in
+  aux [] env
+
+let head_names names env =
+  let rec aux acc = function
+    | (name, (ty, v)) :: tl when List.mem name names ->
+        (match ty, v with
+        | Env.ListType ty, Env.ListValue (v :: _) ->
+            aux ((name, (ty, v)) :: acc) tl
+        | _ -> assert false)
+    | _ :: tl -> aux acc tl
+      (* base pattern may contain only meta names, thus we trash all others *)
+    | [] -> acc
+  in
+  aux [] env
+
+let tail_names names env =
+  let rec aux acc = function
+    | (name, (ty, v)) :: tl when List.mem name names ->
+        (match ty, v with
+        | Env.ListType ty, Env.ListValue (_ :: vtl) ->
+            aux ((name, (Env.ListType ty, Env.ListValue vtl)) :: acc) tl
+        | _ -> assert false)
+    | binding :: tl -> aux (binding :: acc) tl
+    | [] -> acc
+  in
+  aux [] env
+
+let instantiate_level2 env term =
+  let fresh_env = ref [] in
+  let lookup_fresh_name n =
+    try
+      List.assoc n !fresh_env
+    with Not_found ->
+      let new_name = CicNotationUtil.fresh_name () in
+      fresh_env := (n, new_name) :: !fresh_env;
+      new_name
+  in
+  let rec aux env term =
+(*     prerr_endline ("ENV " ^ CicNotationPp.pp_env env); *)
+    match term with
+    | Ast.AttributedTerm (_, term) -> aux env term
+    | Ast.Appl terms -> Ast.Appl (List.map (aux env) terms)
+    | Ast.Binder (binder, var, body) ->
+        Ast.Binder (binder, aux_capture_var env var, aux env body)
+    | Ast.Case (term, indty, outty_opt, patterns) ->
+        Ast.Case (aux env term, indty, aux_opt env outty_opt,
+          List.map (aux_branch env) patterns)
+    | Ast.LetIn (var, t1, t2) ->
+        Ast.LetIn (aux_capture_var env var, aux env t1, aux env t2)
+    | Ast.LetRec (kind, definitions, body) ->
+        Ast.LetRec (kind, List.map (aux_definition env) definitions,
+          aux env body)
+    | Ast.Uri (name, None) -> Ast.Uri (name, None)
+    | Ast.Uri (name, Some substs) ->
+        Ast.Uri (name, Some (aux_substs env substs))
+    | Ast.Ident (name, Some substs) ->
+        Ast.Ident (name, Some (aux_substs env substs))
+    | Ast.Meta (index, substs) -> Ast.Meta (index, aux_meta_substs env substs)
+
+    | Ast.Implicit
+    | Ast.Ident _
+    | Ast.Num _
+    | Ast.Sort _
+    | Ast.Symbol _
+    | Ast.UserInput -> term
+
+    | Ast.Magic magic -> aux_magic env magic
+    | Ast.Variable var -> aux_variable env var
+
+    | _ -> assert false
+  and aux_opt env = function
+    | Some term -> Some (aux env term)
+    | None -> None
+  and aux_capture_var env (name, ty_opt) = (aux env name, aux_opt env ty_opt)
+  and aux_branch env (pattern, term) =
+    (aux_pattern env pattern, aux env term)
+  and aux_pattern env (head, hrefs, vars) =
+    (head, hrefs, List.map (aux_capture_var env) vars)
+  and aux_definition env (var, term, i) =
+    (aux_capture_var env var, aux env term, i)
+  and aux_substs env substs =
+    List.map (fun (name, term) -> (name, aux env term)) substs
+  and aux_meta_substs env meta_substs = List.map (aux_opt env) meta_substs
+  and aux_variable env = function
+    | Ast.NumVar name -> Ast.Num (Env.lookup_num env name, 0)
+    | Ast.IdentVar name -> Ast.Ident (Env.lookup_string env name, None)
+    | Ast.TermVar name -> Env.lookup_term env name
+    | Ast.FreshVar name -> Ast.Ident (lookup_fresh_name name, None)
+    | Ast.Ascription (term, name) -> assert false
+  and aux_magic env = function
+    | Ast.Default (some_pattern, none_pattern) ->
+        let some_pattern_names = CicNotationUtil.names_of_term some_pattern in
+        let none_pattern_names = CicNotationUtil.names_of_term none_pattern in
+        let opt_names =
+          List.filter
+            (fun name -> not (List.mem name none_pattern_names))
+            some_pattern_names
+        in
+        (match opt_names with
+        | [] -> assert false (* some pattern must contain at least 1 name *)
+        | (name :: _) as names ->
+            (match Env.lookup_value env name with
+            | Env.OptValue (Some _) ->
+                (* assumption: if "name" above is bound to Some _, then all
+                 * names returned by "meta_names_of" are bound to Some _ as well
+                 *)
+                aux (unopt_names names env) some_pattern
+            | Env.OptValue None -> aux env none_pattern
+            | _ ->
+                prerr_endline (sprintf
+                  "lookup of %s in env %s did not return an optional value"
+                  name (CicNotationPp.pp_env env));
+                assert false))
+    | Ast.Fold (`Left, base_pattern, names, rec_pattern) ->
+        let acc_name = List.hd names in (* names can't be empty, cfr. parser *)
+        let meta_names =
+          List.filter ((<>) acc_name)
+            (CicNotationUtil.names_of_term rec_pattern)
+        in
+        (match meta_names with
+        | [] -> assert false (* as above *)
+        | (name :: _) as names ->
+            let rec instantiate_fold_left acc env' =
+              match Env.lookup_value env' name with
+              | Env.ListValue (_ :: _) ->
+                  instantiate_fold_left 
+                    (let acc_binding =
+                      acc_name, (Env.TermType, Env.TermValue acc)
+                     in
+                     aux (acc_binding :: head_names names env') rec_pattern)
+                    (tail_names names env')
+              | Env.ListValue [] -> acc
+              | _ -> assert false
+            in
+            instantiate_fold_left (aux env base_pattern) env)
+    | Ast.Fold (`Right, base_pattern, names, rec_pattern) ->
+        let acc_name = List.hd names in (* names can't be empty, cfr. parser *)
+        let meta_names =
+          List.filter ((<>) acc_name)
+            (CicNotationUtil.names_of_term rec_pattern)
+        in
+        (match meta_names with
+        | [] -> assert false (* as above *)
+        | (name :: _) as names ->
+            let rec instantiate_fold_right env' =
+              match Env.lookup_value env' name with
+              | Env.ListValue (_ :: _) ->
+                  let acc = instantiate_fold_right (tail_names names env') in
+                  let acc_binding =
+                    acc_name, (Env.TermType, Env.TermValue acc)
+                  in
+                  aux (acc_binding :: head_names names env') rec_pattern
+              | Env.ListValue [] -> aux env base_pattern
+              | _ -> assert false
+            in
+            instantiate_fold_right env)
+    | Ast.If (_, p_true, p_false) as t ->
+        aux env (CicNotationUtil.find_branch (Ast.Magic t))
+    | Ast.Fail -> assert false
+    | _ -> assert false
+  in
+  aux env term
+
+  (* initialization *)
+
+let _ = load_patterns21 []
+