elispr.ex

defmodule Elispr do
  def parse(s) do
    s |> String.replace("(", " [ ")
    |> String.replace(")", " ] ")
    |> String.replace(~r/([^\[\]\d\s]\S*)/, ":\\1")
    |> String.replace(~r/([^\s\[:]+)/, "\\1,")
    |> String.trim
    |> String.trim_trailing(",")
    |> Code.eval_string
    |> elem(0)
  end

  def translate([:+ | args]) do
    {:+, [], args}
  end

  def eval(s) do
    s |> parse |> translate |> Code.eval_quoted |> elem(0)
  end
end