class Nokogiri::CSS::Parser

def [] string
  return unless @cache_on
  @mutex.synchronize { @cache[string] }
end

def []= string, value
  return value unless @cache_on
  @mutex.synchronize { @cache[string] = value }
end

def clear_cache
  @mutex.synchronize { @cache = {} }
end

def initialize namespaces = {}
  @namespaces = namespaces
  super()
end

def on_error error_token_id, error_value, value_stack
  after = value_stack.compact.last
  raise SyntaxError.new("unexpected '#{error_value}' after '#{after}'")
end

def parse selector
  @warned ||= false
  unless @warned
    $stderr.puts('Nokogiri::CSS::Parser.parse is deprecated, call Nokogiri::CSS.parse(), this will be removed August 1st or version 1.4.0 (whichever is first)')
    @warned = true
  end
  new.parse selector
end

def without_cache &block
  tmp = @cache_on
  @cache_on = false
  block.call
  @cache_on = tmp
end

def xpath_for string, options={}
  key = "#{string}#{options[:ns]}#{options[:prefix]}"
  v = self.class[key]
  return v if v
  args = [
    options[:prefix] || '//',
    options[:visitor] || XPathVisitor.new
  ]
  self.class[key] = parse(string).map { |ast|
    ast.to_xpath(*args)
  }
end