code: function error(m, config) { 
          var w = walker,
              conf = config || {},
              c = isset(conf['char']) ? conf['char'] : w.chnum,
              l = isset(conf.line) ? conf.line : w.linenum;
          return {
              name: "ParseError",
              message: m + " at line " + (l + 1) + ' char ' + (c + 1),
              walker: w,
              tokens: tokens
          };
      }
docs: oops