code: function (description, errdesc) {
  
          //TODO: errdesc is a bit vague
          var desc = {
              description : description
          };
          if (errdesc) {
              if (errdesc.line) { // Integers
                  desc.line = errdesc.line;
                  desc.column = errdesc.column;
              }
              if (errdesc.code) { // String
                  desc.code = errdesc.code;
              }
              if (errdesc.suberrors) { // Array of String
                  desc.suberrors = errdesc.suberrors;
              }
          }
          this.errors.push(desc);
      }
docs: Adds an error to the current error list.
  @param {String} description the error description
  @param {Object} errdesc additional object (block, node, ...) which can contain additional info about the error (line/column number, code).