base: new S3 module, access to underlying R value

lib/base/OCamlR_base.ml

@@ -1,6 +1,5 @@
 open OCamlR
-
-type any
+open OCamlR_wraputils
 
 module Stubs = OCamlR_base_stubs
 module Stubs2 = OCamlR_base_stubs2
@@ -14,8 +13,17 @@ let subset_ii x i j = Stubs2.subset_ii x (R.int i) (R.int j)
 let subset2_i x i = Stubs2.subset2_i x (R.int i)
 let subset2_s x s = Stubs2.subset2_s x (R.string s)
 
+module S3 = struct
+  type t = t R.t
+  let r x = x
+  let _class_ =
+    let symbol = R.symbol "class" in
+    fun (x : t) ->
+      R.strings_of_t (R.eval symbol [ R.arg ident x ])
+end
+
 module Environment = struct
-  type t = any R.t
+  include S3
   let create () = Stubs.new'env ()
   let unsafe_get env ~class_ x =
     let y = Stubs2.subset2_s env (R.string x) in
@@ -25,20 +33,16 @@ module Environment = struct
     else None
 end
 
-module Dataframe_common = struct
+module Dataframe = struct
+  include S3
+
   let dim x =
     match Stubs.dim'data'frame ~x () |> R.ints_of_t with
     | [| i ; j |] -> (i, j)
     | _ -> assert false
-end
-
-module Dataframe = struct
-  type t = any R.t
 
   let of_env env x =
     Environment.unsafe_get env ~class_:"data.frame" x
-
-  include Dataframe_common
 end
 
 let sample ?replace ?prob ~size x =

lib/base/OCamlR_base.mli

@@ -2,15 +2,25 @@
 
 open OCamlR
 
+module S3 : sig
+  type t
+
+  val r : t -> t R.t
+  val _class_ : t -> string array
+end
+
 module Environment : sig
   type t
+  include module type of S3 with type t := t
 
   val create : unit -> t
   (** wrapper for [new.env] *)
 end
 
 module Dataframe : sig
   type t
+  include module type of S3 with type t := t
+
   val of_env : Environment.t -> string -> t option
   val dim : t -> int * int
 end

lib/base/dune

@@ -2,7 +2,7 @@
  (name            OCamlR_base)
  (public_name     ocaml-r.base)
  (wrapped         false)
- (libraries       ocaml-r.interpreter))
+ (libraries       ocaml-r.interpreter ocaml-r.wraputils))
 
 (rule
  (targets OCamlR_base_stubs.ml)