Extract start function for options

lib/options.ex

@@ -3,12 +3,8 @@ defmodule Options do
     clear_screen: false
   }
 
-  def parse(args) do
-    options = Enum.reduce(args, @defaults, fn(arg, acc) ->
-      Map.merge(acc, parse_argument(arg))
-    end)
-
-    Agent.start_link(fn -> options end, name: __MODULE__)
+  def start(args) do
+    Agent.start_link(fn -> parse(args) end, name: __MODULE__)
   end
 
   def clear_screen? do
@@ -17,6 +13,12 @@ defmodule Options do
     end)
   end
 
+  defp parse(args) do
+    Enum.reduce(args, @defaults, fn(arg, acc) ->
+      Map.merge(acc, parse_argument(arg))
+    end)
+  end
+
   def parse_argument("--clear-screen"), do: %{ clear_screen: true}
   def parse_argument(_), do: %{}
 end