From: Joel VanderWerf <vjoel@...>
Date: 2005-09-16T01:31:37+09:00
Subject: Re: classifying exceptions

nobuyoshi nakada wrote:
> Hi,
> 
> At Thu, 15 Sep 2005 14:57:22 +0900,
> Joel VanderWerf wrote in [ruby-talk:156196]:
> 
>>Now, here's another option, but is there anything wrong with it?
>>
>>module NetworkRaisable; end
>>class Errno::EPROTO; include NetworkRaisable; end
>>class Errno::ECONNREFUSED; include NetworkRaisable; end
>># and so on
>>
>>begin
>>  raise Errno::ECONNREFUSED
>>rescue NetworkRaisable
>>  puts "OK!"
>>end
> 
> 
> Actually, an exception, to be caught, doesn't have to be
> including target module always.
> 
>   module NetworkRaisable
>     def self.===(ex)
>       case ex
>       when Errno::EPROTO, Errno::ECONNREFUSED: true
>       end
>     end
>   end
> 

Thanks, that's better. I forgot rescue uses case-matching. And it avoids
modifying ruby built-in classes. (And NetworkRaisable doesn't even have
to be a module.)

-- 
      vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407