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_______________________________________________________________ *)
15 type bind = Void (* exclusion *)
16 | Abst of term (* abstraction *)
17 | Abbr of term (* abbreviation *)
19 and term = Sort of int (* hierarchy index *)
20 | LRef of int (* location *)
21 | GRef of uri (* reference *)
22 | Cast of term * term (* type, term *)
23 | Appl of term * term (* argument, function *)
24 | Bind of int * id * bind * term (* location, name, binder, scope *)
26 type obj = int * uri * bind (* age, uri, binder, contents *)
28 type item = obj option
30 type context = (int * id * bind) list (* location, name, binder *)
32 type message = (context, term) Log.item list
34 (* Currified constructors ***************************************************)
42 let cast u t = Cast (u, t)
44 let appl u t = Appl (u, t)
46 let bind l id b t = Bind (l, id, b, t)
48 let bind_abst l id u t = Bind (l, id, Abst u, t)
50 let bind_abbr l id v t = Bind (l, id, Abbr v, t)
52 (* location handling functions **********************************************)
56 let new_location () = let loc = !location in incr location; loc
58 let locations () = !location
60 (* context handling functions ***********************************************)
62 let empty_context = []
64 let push f es l id b =
65 let c = (l, id, b) :: es in f c
67 let append f es1 es2 =
68 f (List.append es2 es1)
73 let contents f es = f es
76 let rec aux = function
78 | (l, id, b) :: tl -> if l = i then f (Some (id, b)) else aux tl