def get_class_specification
      tk = get_tk
      return "self" if tk.kind_of?(TkSELF)
        
      res = ""
      while tk.kind_of?(TkCOLON2) ||
          tk.kind_of?(TkCOLON3)   ||
          tk.kind_of?(TkCONSTANT)   
        
        res += tk.text
        tk = get_tk
      end

      unget_tk(tk)
      skip_tkspace(false)

      get_tkread # empty out read buffer

      tk = get_tk

      case tk
      when TkNL, TkCOMMENT, TkSEMICOLON
        unget_tk(tk)
        return res
      end

      res += parse_call_parameters(tk)
      res
    end
def get_class_specification
      tk = get_tk
      return "self" if tk.kind_of?(TkSELF)
        
      res = ""
      while tk.kind_of?(TkCOLON2) ||
          tk.kind_of?(TkCOLON3)   ||
          tk.kind_of?(TkCONSTANT)   
        
        res += tk.text
        tk = get_tk
      end

      unget_tk(tk)
      skip_tkspace(false)

      get_tkread # empty out read buffer

      tk = get_tk

      case tk
      when TkNL, TkCOMMENT, TkSEMICOLON
        unget_tk(tk)
        return res
      end

      res += parse_call_parameters(tk)
      res
    end
Return a superclass, which can be either a constant
 of an expression