class Thor::LineEditor::Readline

def self.available?
  Object.const_defined?(:Readline)
end

def add_to_history?
  options.fetch(:add_to_history, true)
end

def completion_options
  options.fetch(:limited_to, [])
end

def completion_proc
  if use_path_completion?
    Proc.new { |text| PathCompletion.new(text).matches }
  elsif completion_options.any?
    Proc.new do |text|
      completion_options.select { |option| option.start_with?(text) }
    end
  end
end

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

def use_path_completion?
  options.fetch(:path, false)
end