From: Florian Gross <flgr@...>
Date: 2004-10-01T08:15:00+09:00
Subject: Re: Calling super methods

--------------010802000800080906080708
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit

Grzegorz Dostatni wrote:

> Is it possible to call a method of a superclass? Let's say I have a
> instance of class Bar ( subclassed from Foo).
> Both Foo and Bar define a function h()
> 
> I want to call a.h() and have it go the Foo's implementation if it,
> without going through the super() call (ie. do it from outside the
> object).

Ah, this has been asked before. I attached my implementation. With this 
one you don't need to pass the method name.

Regards,
Florian Gross


--------------010802000800080906080708
Content-Type: text/plain;
 name="superjump.rb"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="superjump.rb"

# Like super this calls methods from the inheritance chain which this
# method is replacing. However this version jumps over one or more
# methods in the inheritance chain. It is used like this:
#
#   class X
#     def it; p "X#it"; end
#   end
#   
#   class Y < X
#     def it; p "Y#it"; end
#   end
#   
#   class Z < Y
#     def it
#       p "Z#it"
#       superjump
#     end
#   end
#   
#   Z.new.it # outputs "X#it", "Z#it"
#
# Be careful. This method can't automatically pass the arguments of the
# caller like super does. You'll have to manually supply them.
def superjump(gap = 0, *args, &block)
  method_name = caller[0][/in `(.*?)'/, 1].intern
  klass = self.class.ancestors[1 + gap]
  klass.instance_method(method_name).bind(self).call(*args, &block)
end

--------------010802000800080906080708--