enables enumeration of objects in the knowledge base (#1212)

Adds the `objects` function that returns a sequence of all objects in
the knowledge base.

Author: ivg

lib/knowledge/bap_knowledge.ml

@@ -2889,6 +2889,10 @@ module Knowledge = struct
               Format.fprintf ppf "@,%a)@]@\n"
                 (Sexp.pp_hum_indent 2) (Dict.sexp_of_t data)))
 
+  let objects cls = objects cls >>| fun {vals} ->
+    Map.to_sequence vals |>
+    Sequence.map ~f:fst
+
   module Rule = struct
     type def = Registry.def
     type doc = Registry.doc

lib/knowledge/bap_knowledge.mli

@@ -152,6 +152,10 @@ module Knowledge : sig
   (** a fully qualified name  *)
   type name
 
+  (** [objects cls] is a seqeuence of all objects of the class [cls].
+      @since 2.2.0  *)
+  val objects : ('a,_) cls -> 'a obj Sequence.t t
+
   (** [collect p x] collects the value of the property [p].
 
       If the object [x] doesn't have a value for the property [p] and