gistfile1.ex

defprotocol WhizBang do
  def specific(_)
  def common(_)
end

defrecord Foo, name: "foo"
defrecord Bar, name: "bar"

defmodule Common do
  def common(arg), do: IO.puts "Common.common: #{inspect arg}"
end

defimpl WhizBang, for: Foo do
  defdelegate common(foo), to: Common
  def specific(_foo), do: IO.puts "specific Foo"
end

defimpl WhizBang, for: Bar do
  defdelegate common(bar), to: Common
  def specific(_bar), do: IO.puts "specific Bar"
end