class Capybara::Selector::CSS

def self.escape(str)
  value = str.dup
  out = +''
  out << value.slice!(0...1) if value.match?(/^[-_]/)
  out << (value[0].match?(NMSTART) ? value.slice!(0...1) : escape_char(value.slice!(0...1)))
  out << value.gsub(/[^a-zA-Z0-9_-]/) { |char| escape_char char }
  out
end

def self.escape_char(char)
  char.match?(%r{[ -/:-~]}) ? "\\#{char}" : format('\\%06<hex>x', hex: char.ord)
end

def self.split(css)
  Splitter.new.split(css)
end