class RDoc::Options

def generator_descriptions
  lengths = []
  generators = RDoc::RDoc::GENERATORS.map do |name, generator|
    lengths << name.length
    description = generator::DESCRIPTION if
      generator.const_defined? :DESCRIPTION
    [name, description]
  end
  longest = lengths.max
  generators.sort.map do |name, description|
    if description then
      "  %-*s - %s" % [longest, name, description]
    else
      "  #{name}"
    end
  end.join "\n"
end