core: RDF.Serialization.Encoder behaviour

lib/rdf/serialization/encoder.ex

@@ -0,0 +1,23 @@
+defmodule RDF.Serialization.Encoder do
+  @moduledoc false
+
+  @callback encode(RDF.Dataset, keyword) :: keyword(String.t)
+  @callback encode!(RDF.Dataset, keyword) :: String.t
+
+
+  defmacro __using__(_) do
+    quote bind_quoted: [], unquote: true do
+      @behaviour unquote(__MODULE__)
+
+      def encode!(data, opts \\ []) do
+        case encode(data, opts) do
+          {:ok,    data}   -> data
+          {:error, reason} -> raise reason
+        end
+      end
+
+      defoverridable [encode!: 2]
+    end
+  end
+
+end