class Capybara::Selector::XPathBuilder

def regexp_to_xpath_conditions(regexp)
  condition = XPath.current
  condition = condition.uppercase if regexp.casefold?
  Selector::RegexpDisassembler.new(regexp).alternated_substrings.map do |strs|
    strs.map { |str| condition.contains(str) }.reduce(:&)
  end.reduce(:|)
end