class Thor::Options

def parse_boolean(switch)

--foo=false, --no-foo or --skip-foo for false values.
Parse boolean values which can be given as --foo=true or --foo for true values, or

def parse_boolean(switch)
  if current_is_value?
    if ["true", "TRUE", "t", "T", true].include?(peek)
      shift
      true
    elsif ["false", "FALSE", "f", "F", false].include?(peek)
      shift
      false
    else
      @switches.key?(switch) || !no_or_skip?(switch)
    end
  else
    @switches.key?(switch) || !no_or_skip?(switch)
  end
end