class Thor::LineEditor::Readline

def readline
  if echo?
    ::Readline.completion_append_character = nil
    # Ruby 1.8.7 does not allow Readline.completion_proc= to receive nil.
    if complete = completion_proc
      ::Readline.completion_proc = complete
    end
    ::Readline.readline(prompt, add_to_history?)
  else
    super
  end
end