code: function(source) {
          	// transform tokens
  	 		var pos = 0;
  	 		return _.map(this.lex(source), function(token) {
  	 			if (token.type == 'line') {
  	 				token.value = getNewline(source, pos);
  	 			}
  	 			
  	 			return {
  	 				type: token.type,
  	 				start: pos,
  	 				end: (pos += token.value.length)
  	 			};
  			});
  		}
docs: Tokenizes CSS source
  @param {String} source
  @returns {Array}