# File lib/main/parameter.rb, line 222
    def add_handlers e
      esc = 
        class << e
          self
        end

      this = self

      %w[ before instead after ].each do |which|
        getter = "error_handler_#{ which }"
        query = "error_handler_#{ which }?"
        if send(query)
          handler = send getter 
          esc.module_eval do
            define_method(getter) do |main|
              main.instance_eval_block self, &handler
            end
          end
        end
      end
    end