get_in.exs

authors = [
  %{ name: "Jose", langauge: "Elixir" },
  %{ name: "Matz", langauge: "Ruby" },
  %{ name: "Larry", language: "Perl" }
]

language_with_an_r = fn (:get, collection, next_fn) ->
  for row <- collection do
    if String.contains?(row.language, "r") do
      next_fn.(row)
    end
  end
end

get_in(authors, [langauge_with_an_r, :name]) # => ["Jose", nil, "Larry"]