Get rid of the tagged OID

This means we no longer accept any iolist in some of the functions,
but we might bring it back later.

There is also a new function, geef_ref:create_symbolic() to create
symbolic references, since we can no longer differentiate between a
name and an OID.

lib/geef/oid.ex

@@ -1,22 +1,6 @@
-defrecord Geef.Oid, Record.extract(:geef_oid, from: "src/geef_records.hrl") do
-  alias Geef.Oid
+defmodule Geef.Oid do
 
-  @doc false
-  defmacro to_erl(oid) do
-    quote do
-      set_elem(unquote(oid), 0, :geef_oid)
-    end
-  end
-
-  @doc false
-  defmacro from_erl(oid) do
-    quote do
-      set_elem(unquote(oid), 0, Geef.Oid)
-    end
-  end
-
-  defp maybe_oid({:ok, oid}), do: from_erl(oid)
-  defp maybe_oid(error = {:error, _}), do: error
+  @type t :: <<_ :: 160>>
 
   @spec parse(iolist) :: t
   def parse(str) do
@@ -24,8 +8,8 @@ defrecord Geef.Oid, Record.extract(:geef_oid, from: "src/geef_records.hrl") do
   end
 
   @spec hex(t) :: String.t
-  def hex(oid = Oid[]) do
-    :geef_oid.hex(to_erl(oid))
+  def hex(oid) do
+    :geef_oid.hex(oid)
   end
 
 end

lib/geef/reference.ex

@@ -1,22 +1,9 @@
 defrecord Geef.Reference, Record.extract(:geef_reference, from: "src/geef_records.hrl") do
   import Geef
   alias Geef.Reference
-  alias Geef.Oid
-  import Oid, only: :macros
 
-  def from_erl(ref) do
-    case set_elem(ref, 0, Geef.Reference) do
-      ref = Reference[type: :symbolic] -> ref
-      ref = Reference[type: :oid, target: oid] -> ref.target(set_elem(oid, 0, Geef.Oid))
-    end
-  end
-
-  def to_erl(ref = Reference[type: :symbolic]) do
-    set_elem(ref, 0, :geef_reference)
-  end
-  def to_erl(ref = Reference[type: :oid, target: oid]) do
-    ref |> set_elem(0, :geef_reference) |> set_elem(4, set_elem(oid, 0, :geef_oid))
-  end
+  def from_erl(ref), do: set_elem(ref, 0, Geef.Reference)
+  def to_erl(ref), do: set_elem(ref, 0, :geef_reference)
 
   defp maybe_ref({:ok, ref}), do: {:ok, Reference.from_erl ref}
   defp maybe_ref(err = {:error, _}), do: err