code: function consumeIdent(stream) {
  	stream.start = stream.pos;
  	stream.eatWhile(isIdentPrefix);
  	stream.eatWhile(isIdent);
  	return stream.start !== stream.pos ? stream.current() : null;
  }
docs: Consumes CSS property identifier from given stream
  @param  {StreamReader} stream
  @return {String}