class Capybara::Selector::RegexpDisassembler::Expression

def extract_strings(process_alternatives)
  strings = []
  each do |exp|
    next if exp.ignore?
    next strings.push(nil) if exp.optional? && !process_alternatives
    next strings.push(exp.alternative_strings) if exp.alternation? && process_alternatives
    strings.concat(exp.strings(process_alternatives))
  end
  strings
end