Tap a method in elixir(similar to ruby)

tap.exs

defmodule Tap do
  defmacro tap(tapped_value, do: yield) do
    quote do
      var!(t) = unquote(tapped_value)
      unquote(yield)
      var!(t)
    end
  end

  defmacro tap(tapped_value, :return, do: yield) do
    quote do
      var!(t) = unquote(tapped_value)
      unquote(yield)
    end
  end
end

defmodule Test do
  import Tap

  def run do
    tap List do
      IO.puts t.first([1, 2, 3])
      IO.puts t.last([1, 2, 4])
    end
  end

  def run(:return) do
    tap List, :return do
      [1, 2, 3]
      |> t.first()
      |> t.wrap()
    end
  end
end


IO.puts "=Tap="
IO.inspect Test.run

IO.puts "\n=Tap without return="
IO.inspect Test.run :return

# Output
# =Tap=
# 1
# 4
# List
#
# =Tap without return=
# [1]