new kernel basic_ag (with absolute local references)

[helm.git] / helm / software / lambda-delta / basic_ag / bag.ml

diff --git a/helm/software/lambda-delta/basic_ag/bag.ml b/helm/software/lambda-delta/basic_ag/bag.ml
new file mode 100644 (file)
index 0000000..d0c193a
--- /dev/null
+++ b/helm/software/lambda-delta/basic_ag/bag.ml
@@ -0,0 +1,78 @@
+(*
+    ||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 = NUri.uri
+type id = Aut.id
+
+type bind = Void         (* exclusion *)
+          | Abst of term (* abstraction *)
+          | Abbr of term (* abbreviation *)
+
+and term = Sort of int                    (* hierarchy index *)
+         | LRef of int                    (* location *)
+         | GRef of uri                    (* reference *)
+         | Cast of term * term            (* type, term *)
+         | Appl of term * term            (* argument, function *)
+         | Bind of int * id * bind * term (* location, name, binder, scope *)
+
+type obj = int * uri * bind (* age, uri, binder, contents *)
+
+type item = obj option
+
+type context = (int * id * bind) list (* location, name, binder *) 
+
+type message = (context, term) Log.item list
+
+(* Currified constructors ***************************************************)
+
+let abst w = Abst w
+
+let abbr v = Abbr v
+
+let lref i = LRef i
+
+let cast u t = Cast (u, t)
+
+let appl u t = Appl (u, t)
+
+let bind l id b t = Bind (l, id, b, t)
+
+let bind_abst l id u t = Bind (l, id, Abst u, t)
+
+let bind_abbr l id v t = Bind (l, id, Abbr v, t)
+
+(* location handling functions **********************************************)
+
+let location = ref 0
+
+let new_location () = let loc = !location in incr location; loc
+
+(* context handling functions ***********************************************)
+
+let empty_context = []
+
+let push f es l id b =
+   let c = (l, id, b) :: es in f c
+
+let append f es1 es2 = 
+   f (List.append es2 es1)
+
+let map f map es =
+   Cps.list_map f map es
+
+let contents f es = f es
+
+let get f es i =
+   let rec aux = function
+      | []               -> f None
+      | (l, id, b) :: tl -> if l = i then f (Some (id, b)) else aux tl
+   in
+   aux es