pipes pipes pipes

piper.ex

defmodule PipesX do
  defmacro pipe_with(fun, pipes) do
    IO.puts "Will reduce over: #{inspect Macro.unpipe(pipes)}"
    Enum.reduce Macro.unpipe(pipes), &(reduce_with &1, &2, fun)
  end

  defp reduce_with( {segment, pos}, acc, outer ) do
    IO.puts "reduce_with: Got #{inspect segment} at #{inspect pos}"
    quote do
      inner = fn(x) ->
        res = unquote Macro.pipe((quote do: x), segment, pos)
        IO.puts "(inner) Got #{inspect x}, res: #{inspect res}"
        res
      end
      case unquote(acc) do
        {ac, pos} -> 
          res = unquote(outer).(ac, inner)
          IO.puts "(outer) Got #{inspect ac}, #{inspect pos}, res: #{inspect res}"
          res
        ac      -> 
          IO.puts "Got #{inspect ac}"
          unquote(outer).(ac, inner)
      end
    end
  end
end

defmodule Simple do
  require PipesX
  def inc(x), do: x + 1
  def double(x), do: x * 2
  
  def with_pipes_map do
    PipesX.pipe_with fn(acc, f) -> Enum.map(acc, f) end,
      ([ 1, 2, 3] |> inc |> double)
  end
end