add CCHashtbl.Poly and fix issue in Containers (close #46)

src/core/CCHashtbl.ml

@@ -10,6 +10,7 @@ type 'a printer = Format.formatter -> 'a -> unit
 
 (** {2 Polymorphic tables} *)
 
+module Poly = struct
   let get tbl x =
     try Some (Hashtbl.find tbl x)
     with Not_found -> None
@@ -135,6 +136,9 @@ let print pp_k pp_v fmt m =
          Format.pp_print_cut fmt ()
       ) m;
     Format.fprintf fmt "}@]"
+end
+
+include Poly
 
 (** {2 Functor} *)
 

src/core/CCHashtbl.mli

@@ -12,6 +12,9 @@ type 'a printer = Format.formatter -> 'a -> unit
 
 (** {2 Polymorphic tables} *)
 
+(** This sub-module contains the extension of the standard polymorphic hashtbl. *)
+
+module Poly : sig
   val get : ('a,'b) Hashtbl.t -> 'a -> 'b option
   (** Safe version of {!Hashtbl.find} *)
 
@@ -102,6 +105,9 @@ val get_or_add : ('a, 'b) Hashtbl.t -> f:('a -> 'b) -> k:'a -> 'b
   val print : 'a printer -> 'b printer -> ('a, 'b) Hashtbl.t printer
   (** Printer for table
       @since 0.13 *)
+end
+
+include module type of Poly
 
 (** {2 Functor} *)
 

src/core/containers.ml

@@ -44,7 +44,7 @@ module Hashtbl = struct
      and module Make = Hashtbl.Make
      and type ('a,'b) t = ('a,'b) Hashtbl.t
   )
-  (* still unable to include CCHashtbl itself, for the polymorphic functions *)
+  include CCHashtbl.Poly
   module type S' = CCHashtbl.S
   module Make' = CCHashtbl.Make
 end