code: def reference(self, t, i, in_group=False):
          
  
          current = []
  
          if not in_group and t == "R":
              current.append(self._re_line_break)
          elif t == 'e':
              current.extend(self._re_escape)
          else:
              current.extend(["\\", t])
          return current
docs: Handle references.