From: Joel VanderWerf <vjoel@...>
Date: 2005-09-15T14:57:22+09:00
Subject: classifying exceptions


There are many places in my code that need to catch any error generated
by a network system call, but I don't want to catch everything that
inherits from SystemCallError. This is my current code:

ALL_NETWORK_ERRORS = [Errno::ECONNRESET, Errno::ECONNABORTED,
  Errno::ECONNREFUSED, Errno::EPIPE, IOError, Errno::ETIMEDOUT]

ALL_NETWORK_ERRORS << Errno::EPROTO if defined?(Errno::EPROTO)
  # this doesn't exist on mswin32

begin
  raise Errno::ECONNREFUSED
rescue *ALL_NETWORK_ERRORS
  puts "OK!"
end

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

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