# File bin/el4r-instance, line 469
    def with_preserved_block(funcexpr, mode, *args, &block)
      mode = el(mode)
      subfuncexpr = "#{mode.expression}--el4r-function"
      block ||= lambda{}
      defun(subfuncexpr, &block) 
      args << el("(#{subfuncexpr})")

      funcall_internal(funcexpr, mode, *args)
    end