class Nokogiri::CSS::Tokenizer

def _next_token
  text = @ss.peek(1)
  @lineno  +=  1  if text == "\n"
  token = case @state
  when nil
    case
    when (text = @ss.scan(/has\([\s]*/))
       action { [:HAS, text] }
    when (text = @ss.scan(/[-@]?([_A-Za-z]|[^\0-\177]|\\[0-9A-Fa-f]{1,6}(\r\n|[\s])?|\\[^\n\r\f0-9A-Fa-f])([_A-Za-z0-9-]|[^\0-\177]|\\[0-9A-Fa-f]{1,6}(\r\n|[\s])?|\\[^\n\r\f0-9A-Fa-f])*\([\s]*/))
       action { [:FUNCTION, text] }
    when (text = @ss.scan(/[-@]?([_A-Za-z]|[^\0-\177]|\\[0-9A-Fa-f]{1,6}(\r\n|[\s])?|\\[^\n\r\f0-9A-Fa-f])([_A-Za-z0-9-]|[^\0-\177]|\\[0-9A-Fa-f]{1,6}(\r\n|[\s])?|\\[^\n\r\f0-9A-Fa-f])*/))
       action { [:IDENT, text] }
    when (text = @ss.scan(/\#([_A-Za-z0-9-]|[^\0-\177]|\\[0-9A-Fa-f]{1,6}(\r\n|[\s])?|\\[^\n\r\f0-9A-Fa-f])+/))
       action { [:HASH, text] }
    when (text = @ss.scan(/[\s]*~=[\s]*/))
       action { [:INCLUDES, text] }
    when (text = @ss.scan(/[\s]*\|=[\s]*/))
       action { [:DASHMATCH, text] }
    when (text = @ss.scan(/[\s]*\^=[\s]*/))
       action { [:PREFIXMATCH, text] }
    when (text = @ss.scan(/[\s]*\$=[\s]*/))
       action { [:SUFFIXMATCH, text] }
    when (text = @ss.scan(/[\s]*\*=[\s]*/))
       action { [:SUBSTRINGMATCH, text] }
    when (text = @ss.scan(/[\s]*!=[\s]*/))
       action { [:NOT_EQUAL, text] }
    when (text = @ss.scan(/[\s]*=[\s]*/))
       action { [:EQUAL, text] }
    when (text = @ss.scan(/[\s]*\)/))
       action { [:RPAREN, text] }
    when (text = @ss.scan(/[\s]*\[[\s]*/))
       action { [:LSQUARE, text] }
    when (text = @ss.scan(/[\s]*\]/))
       action { [:RSQUARE, text] }
    when (text = @ss.scan(/[\s]*\+[\s]*/))
       action { [:PLUS, text] }
    when (text = @ss.scan(/[\s]*>[\s]*/))
       action { [:GREATER, text] }
    when (text = @ss.scan(/[\s]*,[\s]*/))
       action { [:COMMA, text] }
    when (text = @ss.scan(/[\s]*~[\s]*/))
       action { [:TILDE, text] }
    when (text = @ss.scan(/\:not\([\s]*/))
       action { [:NOT, text] }
    when (text = @ss.scan(/-?([0-9]+|[0-9]*\.[0-9]+)/))
       action { [:NUMBER, text] }
    when (text = @ss.scan(/[\s]*\/\/[\s]*/))
       action { [:DOUBLESLASH, text] }
    when (text = @ss.scan(/[\s]*\/[\s]*/))
       action { [:SLASH, text] }
    when (text = @ss.scan(/U\+[0-9a-f?]{1,6}(-[0-9a-f]{1,6})?/))
       action {[:UNICODE_RANGE, text] }
    when (text = @ss.scan(/[\s]+/))
       action { [:S, text] }
    when (text = @ss.scan(/"([^\n\r\f"]|\n|\r\n|\r|\f|[^\0-\177]|\\[0-9A-Fa-f]{1,6}(\r\n|[\s])?|\\[^\n\r\f0-9A-Fa-f])*"|'([^\n\r\f']|\n|\r\n|\r|\f|[^\0-\177]|\\[0-9A-Fa-f]{1,6}(\r\n|[\s])?|\\[^\n\r\f0-9A-Fa-f])*'/))
       action { [:STRING, text] }
    when (text = @ss.scan(/./))
       action { [text, text] }
    else
      text = @ss.string[@ss.pos .. -1]
      raise  ScanError, "can not match: '" + text + "'"
    end  # if
  else
    raise  ScanError, "undefined state: '" + state.to_s + "'"
  end  # case state
  token
end  # def _next_token

def action
  yield
end

def load_file( filename )
  @filename = filename
  open(filename, "r") do |f|
    scan_setup(f.read)
  end
end

def next_token
  return if @ss.eos?
  
  # skips empty actions
  until token = _next_token or @ss.eos?; end
  token
end

def scan_file( filename )
  load_file(filename)
  do_parse
end

def scan_setup(str)
  @ss = StringScanner.new(str)
  @lineno =  1
  @state  = nil
end

def scan_str(str)
  scan_setup(str)
  do_parse
end