composition macro elixir.sydney

composition.ex

defmodule Composition do
  defmacro compose(name, list) do
    arg = Enum.reduce(list, Macro.var(:x, __MODULE__), fn({mod, fun}, acc) ->
      {{:., [], [{:__aliases__, [alias: false], [mod]}, fun]}, [], [acc]}
    end)

    quote do
      def unquote(name)(x) do
        unquote(arg)
      end
    end
  end
end

defmodule Main do
  require Composition

  Composition.compose(:a, [{Enum, :sort}, {Enum, :uniq}, {Enum, :reverse}])

  def hello do
    a([1,5,3,4,1,2,3])
  end
end