match on elixir structs

match on elixir structs.md

iex(149)> %Riak.Object{} = r 
%Riak.Object{bucket: "user", content_type: 'application/json',
 data: "han solo the second", key: "hero",
 metadata: {:dict, 3, 16, 16, 8, 80, 48,
  {[], [], [], [], [], [], [], [], [], [], [], [], [], [], [], []},
  {{[], [], [], [], [], [], [], [], [], [],
    [["content-type", 97, 112, 112, 108, 105, 99, 97, 116, 105, 111, 110, 47,
      106, 115, 111, 110],
     ["X-Riak-VTag", 52, 107, 107, 70, 111, 69, 106, 68, 118, 108, 52, 107, 68,
      50, 97, 121, 86, 55, 104, 121, 56, 68]], [], [],
    [["X-Riak-Last-Modified" | {1461, 97432, 474244}]], [], []}}},
 type: :undefined,
 vclock: <<107, 206, 97, 96, 96, 96, 204, 96, 202, 5, 82, 60, 202, 156, 255, 126, 126, 232, 153, 215, 192, 192, 224, 167, 152, 193, 148, 40, 152, 199, 202, 112, 131, 191, 251, 2, 95, 22, 0>>}
iex(150)> match?(%Riak.Object{}, r)
true
iex(151)> match?(%Riak.Object{}, r)
true
iex(152)> case r do 
...(152)> %Riak.Object{} = r -> true
...(152)> _ -> false
...(152)> end
true
iex(153)> is_map(r) && Map.has_key?(r,:__struct__) && r.__struct__ == Riak.Object
true