From: Pit Capitain <pit@...>
Date: 2005-04-07T16:06:23+09:00
Subject: Re: how to simulate self-style delegation [SuperHash]

itsme213 schrieb:
> "Pit Capitain" <pit@capitain.de> wrote in message
> 
>>   class Person
>>     def delegate_to(role)
>>       @seam.clear if @seam
>>       @seam = Seam.new do |s|
>>         s.instead_of(self, :describe) do role.describe end
>>         s.instead_of(role, :name) do self.name end
>>       end
>>     end
>>   end
> 
> Interesting. I'll give it some thought.
> 
> Would this require knowledge of the internal structure of role#describe? Or
> would it be safe to do the following?
>    (s.methods - Object.instance_methods).each {|m|
>         s.instead_of(role, m.intern) do self.send(m) end
>     }

You have to consider message parameters and blocks. If you want to pass 
them unchanged to the other object you could do it this way:

   (s.methods - Object.instance_methods).each do |m|
     s.instead_of(role, m) do |c|
       self.send(m, *c.args, &c.block)
     end
   end

The seam block is called with one parameter, a call object. Via this 
call object you can get access to the original method call, for example 
at its parameters and the block passed.

Regards,
Pit