2 ||M|| This file is part of HELM, an Hypertextual, Electronic
3 ||A|| Library of Mathematics, developed at the Computer Science
4 ||T|| Department, University of Bologna, Italy.
6 ||T|| HELM is free software; you can redistribute it and/or
7 ||A|| modify it under the terms of the GNU General Public License
8 \ / version 2 or (at your option) any later version.
9 \ / This software is distributed as is, NO WARRANTY.
10 V_______________________________________________________________ *)
12 (* kernel version: basic, relative, global *)
13 (* note : ufficial basic lambda-delta *)
21 type bind = Void (* *)
22 | Abst of N.level * term (* level, type *)
23 | Abbr of term (* body *)
25 and term = Sort of attrs * int (* attrs, hierarchy index *)
26 | LRef of attrs * int (* attrs, position index *)
27 | GRef of attrs * uri (* attrs, reference *)
28 | Cast of attrs * term * term (* attrs, type, term *)
29 | Appl of attrs * term * term (* attrs, argument, function *)
30 | Bind of attrs * bind * term (* attrs, binder, scope *)
32 type entity = term E.entity (* attrs, uri, binder *)
35 (* Cons: tail, relative local environment, attrs, binder *)
36 | Cons of lenv * lenv * attrs * bind
38 (* Currified constructors ***************************************************)
40 let abst n w = Abst (n, w)
44 let lref a i = LRef (a, i)
46 let cast a u t = Cast (a, u, t)
48 let appl a u t = Appl (a, u, t)
50 let bind a b t = Bind (a, b, t)
52 let bind_abst n a u t = Bind (a, Abst (n, u), t)
54 let bind_abbr a v t = Bind (a, Abbr v, t)
56 let bind_void a t = Bind (a, Void, t)
58 (* local environment handling functions *************************************)
62 let push e c a b = Cons (e, c, a, b)
64 let rec get i = function
65 | Null -> Null, Null, [], Void
66 | Cons (e, c, a, b) when i = 0 -> e, c, a, b
67 | Cons (e, _, _, _) -> get (pred i) e
71 (* used in BrgOutput.pp_lenv *)
72 let rec fold_right f map e x = match e with
74 | Cons (e, c, a, b) -> fold_right (map f e c a b) map e x