optpars.ex

  def parse_args(argv) do
    parse = OptionParser.parse(argv, switches: [ help: :boolean,
                                                 from: :string ,
                                                 to:   :string],
                                     aliases:  [ h:    :help,
                                                 f:    :from,
                                                 t:    :to ])
    case parse do
      { [ help: true ], _, _ }         -> :help
      { [ to: to ],             _, _ } -> [ from: '.' , to: to ]
      { [ from: from, to: to ], _, _ } -> [ from: from, to: to ]
      _                                -> :help
    end
  end