class Thor::Options

def current_is_switch?

starts with a hyphen; the second is true if it is a registered switch.
Two booleans are returned. The first is true if the current value

Check if the current value in peek is a registered switch. 
def current_is_switch?
  case peek
  when LONG_RE, SHORT_RE, EQ_RE, SHORT_NUM
    [true, switch?($1)]
  when SHORT_SQ_RE
    [true, $1.split('').any? { |f| switch?("-#{f}") }]
  else
    [false, false]
  end
end