new

# File actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb, line 239
    def initialize(selector, *values)
      raise ArgumentError, "CSS expression cannot be empty" if selector.empty?
      @source = ""
      values = values[0] if values.size == 1 && values[0].is_a?(Array)

      # We need a copy to determine if we failed to parse, and also
      # preserve the original pass by-ref statement.
      statement = selector.strip.dup

      # Create a simple selector, along with negation.
      simple_selector(statement, values).each { |name, value| instance_variable_set("@#{name}", value) }

      @alternates = []
      @depends = nil

      # Alternative selector.
      if statement.sub!(/^\s*,\s*/, "")
        second = Selector.new(statement, values)
        @alternates << second
        # If there are alternate selectors, we group them in the top selector.
        if alternates = second.instance_variable_get(:@alternates)
          second.instance_variable_set(:@alternates, [])
          @alternates.concat alternates
        end
        @source << " , " << second.to_s
      # Sibling selector: create a dependency into second selector that will
      # match element immediately following this one.
      elsif statement.sub!(/^\s*\+\s*/, "")
        second = next_selector(statement, values)
        @depends = lambda do |element, first|
          if element = next_element(element)
            second.match(element, first)
          end
        end
        @source << " + " << second.to_s
      # Adjacent selector: create a dependency into second selector that will
      # match all elements following this one.
      elsif statement.sub!(/^\s*~\s*/, "")
        second = next_selector(statement, values)
        @depends = lambda do |element, first|
          matches = []
          while element = next_element(element)
            if subset = second.match(element, first)
              if first && !subset.empty?
                matches << subset.first
                break
              else
                matches.concat subset
              end
            end
          end
          matches.empty? ? nil : matches
        end
        @source << " ~ " << second.to_s
      # Child selector: create a dependency into second selector that will
      # match a child element of this one.
      elsif statement.sub!(/^\s*>\s*/, "")
        second = next_selector(statement, values)
        @depends = lambda do |element, first|
          matches = []
          element.children.each do |child|
            if child.tag? && subset = second.match(child, first)
              if first && !subset.empty?
                matches << subset.first
                break
              else
                matches.concat subset
              end
            end
          end
          matches.empty? ? nil : matches
        end
        @source << " > " << second.to_s
      # Descendant selector: create a dependency into second selector that
      # will match all descendant elements of this one. Note,
      elsif statement =~ /^\s+\S+/ && statement != selector
        second = next_selector(statement, values)
        @depends = lambda do |element, first|
          matches = []
          stack = element.children.reverse
          while node = stack.pop
            next unless node.tag?
            if subset = second.match(node, first)
              if first && !subset.empty?
                matches << subset.first
                break
              else
                matches.concat subset
              end
            elsif children = node.children
              stack.concat children.reverse
            end
          end
          matches.empty? ? nil : matches
        end
        @source << " " << second.to_s
      else
        # The last selector is where we check that we parsed
        # all the parts.
        unless statement.empty? || statement.strip.empty?
          raise ArgumentError, "Invalid selector: #{statement}"
        end
      end
    end