code: function () {
                  var selectors = [], s, rules, match, debugInfo;
                  
                  save();
  
                  if (env.dumpLineNumbers)
                      debugInfo = getDebugInfo(i, input, env);
  
                  while (s = $(this.selector)) {
                      selectors.push(s);
                      $(this.comment);
                      if (! $(',')) { break }
                      $(this.comment);
                  }
  
                  if (selectors.length > 0 && (rules = $(this.block))) {
                      var ruleset = new(tree.Ruleset)(selectors, rules, env.strictImports);
                      if (env.dumpLineNumbers)
                          ruleset.debugInfo = debugInfo;
                      return ruleset;
                  } else {
                      // Backtrack
                      furthest = i;
                      restore();
                  }
              }
docs: div, .class, body > p {...}