docs: function(parser, reporter){
          var rule = this;
  
          parser.addListener("startrule", function(event){
              var selectors = event.selectors,
                  selector,
                  part,
                  modifier,
                  i, j, k;
  
              for (i=0; i < selectors.length; i++){
                  selector = selectors[i];
                  for (j=0; j < selector.parts.length; j++){
                      part = selector.parts[j];
                      if (part instanceof parserlib.css.SelectorPart){
                          for (k=0; k < part.modifiers.length; k++){
                              modifier = part.modifiers[k];
                              if (modifier.type == "attribute"){
                                  if (/([\~\|\^\$\*]=)/.test(modifier)){
                                      reporter.warn("Attribute selectors with " + RegExp.$1 + " are slow!", modifier.line, modifier.col, rule);
                                  }
                              }
  
                          }
                      }
                  }
              }
          });
      }