code: function SYM(symbol) {
          var _func = 'SYM("' + symbol + '")';
          return function (buffer, index, depth) {
              if (typeof depth === "undefined") { depth = 0; }
              _trace(_func, depth, true);
              var r;
              if (index + symbol.length <= buffer.length && index == buffer.indexOf(symbol, index)) {
                  _trace(_func, depth, false, paka.S.OK);
                  return R.ok(paka.P.SYM, index, symbol.length, null);
              } else {
                  r = R.error(paka.P.SYM, index, null, 'Expects string "' + symbol + '"');
                  _update_last_error(r);
                  _trace(_func, depth, false, paka.S.ERROR);
                  return r;
              }
          };
      }
docs: Symbol: matches a string like "function"