def read_input(prompt, save_hist = true)
      line = prepare_input(prompt)
      return unless line

      history.push(line) if save_hist

      command_queue.concat(split_commands(line))
      command_queue.shift
    end
def read_input(prompt, save_hist = true)
      line = prepare_input(prompt)
      return unless line

      history.push(line) if save_hist

      command_queue.concat(split_commands(line))
      command_queue.shift
    end
Reads a new line from the interface's input stream, parses it into
 commands and saves it to history.

 @return [String] Representing something to be run by the debugger.