rebar.ex

  @rebarconfigscript "rebar.config.script"
  @doc """
  Loads the rebar.config and evaluates rebar.config.script if it
  exists in the given directory.
  """
  def load_config(dir) do
    config_path = Path.join(dir, "rebar.config")
    script_path = Path.join(dir, @rebarconfigscript)

    config = case :file.consult(config_path) do
      { :ok, config } ->
        config
      { :error, :enoent } ->
        []
      { :error, error } ->
        reason = :file.format_error(error)
        raise Mix.Error, message: "Error consulting rebar config #{config_path}: #{reason}"
    end

    if File.exists?(script_path) do
      File.cd!(dir, fn -> eval_script(@rebarconfigscript, config) end)
    else
      config
    end
  end

  defp eval_script(script, config) do
    case :file.script(script, eval_binds(CONFIG: config, SCRIPT: script)) do
      { :ok, config } ->
        config
      { :error, error } ->
        reason = :file.format_error(error)
        raise Mix.Error, message: "Error evaluating rebar config script #{Path.expand(script)}: #{reason}"
    end
  end