class Regexp::Expression::Subexpression

def match_length
  MatchLength.new(self,
                   base_min: map { |exp| exp.match_length.min }.inject(0, :+),
                   base_max: map { |exp| exp.match_length.max }.inject(0, :+),
                   reify: ->{ map { |exp| exp.match_length.to_re }.join })
end