From: Aleksei Guzev <aleksei.guzev@...>
Date: 2001-07-05T22:33:21+09:00
Subject: [ruby-talk:17292] Re: Inheritance

# module MyException
# end

MyException should be derived from Exception to allow other "hardware"
exceptions be raised. Module cannot inherit from a class :(

In http://www.rubycentral.com/book/tut_exceptions.html written that
rescue tests objects against specified class with "kind_of?" method.

But in Ruby 1.6.4 this is not true. Yukihiru Matsumoto said Ruby 1.7.1
would use Class#=== at this place. I.e. the class object should report
whether the parameter falls inside. But I like using "kind_of?", because
then I could write:

	class MyException < Eception; end
	
	class IntDivisionByZero < MyException
	   def kind_of?( klass )
	      if klass == ZeroDivisionError
	         return true
	      else
	         return super( klass )
	      end
	   end
	end

And there would be no problem.

Aleksei Guzev

P.S. Really I don't like this way. It's aka "void*" in C or "pointer" in
Pascal. I like multiple inheritance not allowed in Ruby :(