--- /dev/null
+(*
+ ||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_______________________________________________________________ *)
+
+(* kernel version: complete, relative, global *)
+(* note : fragment of complete lambda-delta serving as abstract layer *)
+
+type uri = Entity.uri
+type id = Entity.id
+type attrs = Entity.attrs
+
+type bind = Abst of term list (* domains *)
+ | Abbr of term list (* bodies *)
+ | Void of int (* number of exclusions *)
+
+and term = TSort of attrs * int (* attrs, hierarchy index *)
+ | TLRef of attrs * int * int (* attrs, position indexes *)
+ | TGRef of attrs * uri (* attrs, reference *)
+ | TCast of attrs * term * term (* attrs, domain, element *)
+ | TAppl of attrs * term list * term (* attrs, arguments, function *)
+ | TProj of attrs * lenv * term (* attrs, closure, member *)
+ | TBind of attrs * bind * term (* attrs, binder, scope *)
+
+and lenv = ESort (* top *)
+ | EProj of lenv * attrs * lenv (* environment, attrs, closure *)
+ | EBind of lenv * attrs * bind (* environment, attrs, binder *)
+
+type entity = term Entity.entity
+
+(* helpers ******************************************************************)
+
+let mk_uri root s =
+ String.concat "/" ["ld:"; "crg"; root; s ^ ".ld"]
+
+let empty_lenv = ESort
+
+let push_bind f lenv a b = f (EBind (lenv, a, b))
+
+let push_proj f lenv a e = f (EProj (lenv, a, e))
+
+let push2 err f lenv attr ?t = match lenv, t with
+ | EBind (e, a, Abst ws), Some t -> f (EBind (e, (attr :: a), Abst (t :: ws)))
+ | EBind (e, a, Abbr vs), Some t -> f (EBind (e, (attr :: a), Abbr (t :: vs)))
+ | EBind (e, a, Void n), None -> f (EBind (e, (attr :: a), Void (succ n)))
+ | _ -> err ()
+
+(* this id not tail recursive *)
+let resolve_lref err f id lenv =
+ let rec aux f i k = function
+ | ESort -> err ()
+ | EBind (tl, a, _) ->
+ let err kk = aux f (succ i) (k + kk) tl in
+ let f j = f i j (k + j) in
+ Entity.resolve err f id a
+ | EProj _ -> assert false (* TODO *)
+ in
+ aux f 0 0 lenv
+
+let rec get_name err f i j = function
+ | ESort -> err i
+ | EBind (tl, a, Abst []) -> get_name err f i j tl
+ | EBind (tl, a, Abbr []) -> get_name err f i j tl
+ | EBind (tl, a, Void 0) -> get_name err f i j tl
+ | EBind (_, a, _) when i = 0 ->
+ let err () = err i in
+ Entity.get_name err f j a
+ | EBind (tl, _, _) ->
+ get_name err f (pred i) j tl
+ | EProj (tl, _, e) ->
+ let err i = get_name err f i j tl in
+ get_name err f i j e