-module U = NUri
-module A = Aut
+(*
+ ||M|| This file is part of HELM, an Hypertextual, Electronic
+ ||A|| Library of Mathematics, developed at the Computer Science
+ ||T|| Department, University of Bologna, Italy.
+ ||I||
+ ||T|| HELM is free software; you can redistribute it and/or
+ ||A|| modify it under the terms of the GNU General Public License
+ \ / version 2 or (at your option) any later version.
+ \ / This software is distributed as is, NO WARRANTY.
+ V_______________________________________________________________ *)
-type uri = U.uri
-type id = A.id
+(* kernel version: basic, relative, global *)
+(* note : ufficial basic lambda-delta *)
-type binder = Abst | Abbr
+type uri = Entity.uri
+type id = Entity.id
+type attrs = Entity.attrs
-type term = Sort of int
- | LRef of int
- | GRef of uri
- | Cast of term * term
- | Appl of term * term
- | Bind of id * binder * term * term
-
+type bind = Void of attrs (* attrs *)
+ | Abst of attrs * term (* attrs, type *)
+ | Abbr of attrs * term (* attrs, body *)
+
+and term = Sort of attrs * int (* attrs, hierarchy index *)
+ | LRef of attrs * int (* attrs, position index *)
+ | GRef of attrs * uri (* attrs, reference *)
+ | Cast of attrs * term * term (* attrs, type, term *)
+ | Appl of attrs * term * term (* attrs, argument, function *)
+ | Bind of bind * term (* binder, scope *)
+
+type entity = term Entity.entity (* attrs, uri, binder *)
+
+type lenv = Null
+(* Cons: tail, relative local environment, binder *)
+ | Cons of lenv * lenv option * bind
+
+(* helpers ******************************************************************)
+
+let mk_uri root s =
+ String.concat "/" ["ld:"; "brg"; root; s ^ ".ld"]
+
+(* Currified constructors ***************************************************)
+
+let abst a w = Abst (a, w)
+
+let abbr a v = Abbr (a, v)
+
+let lref a i = LRef (a, i)
+
+let cast a u t = Cast (a, u, t)
+
+let appl a u t = Appl (a, u, t)
+
+let bind b t = Bind (b, t)
+
+let bind_abst a u t = Bind (Abst (a, u), t)
+
+let bind_abbr a v t = Bind (Abbr (a, v), t)
+
+(* local environment handling functions *************************************)
+
+let empty_lenv = Null
+
+let push f es ?c b =
+ let es = Cons (es, c, b) in f es
+
+let get err f es i =
+ let rec aux j = function
+ | Null -> err ()
+ | Cons (tl, None, b) when j = 0 -> f tl b
+ | Cons (_, Some c, b) when j = 0 -> f c b
+ | Cons (tl, _, _) -> aux (pred j) tl
+ in
+ aux i es
+
+let rec rev_iter f map = function
+ | Null -> f ()
+ | Cons (tl, None, b) ->
+ let f _ = map f tl b in rev_iter f map tl
+ | Cons (tl, Some c, b) ->
+ let f _ = map f c b in rev_iter f map tl
+
+let rec fold_left f map x = function
+ | Null -> f x
+ | Cons (tl, _, b) ->
+ let f x = fold_left f map x tl in
+ map f x b