[Ruby] conditional execution of block / method?

[Bastiaan]

Hi Folks,

This is my first post to this list, and it's not going make me  
popular, I guess..

I have been coding Ruby for a little while now, and I find myself  
doing this sometimes:

if(foo=bar.something)
   foo.something_else
end

Obviously I only want to call #something_else on the output of  
#something if #something is true and settle for nil/false otherwise.

I find this approach tedious. Maybe you people have a nice way around  
this. My noob-approach woud be:

bar.something.if_so.something_else

and have that return nil or false if #something returned nil or false  
itself. I'm aware that this potentially totally un-Rubyesque(?), but  
you'd have to explicitly use the #if_so thingie if this behaviour is  
wanted, so it's not really 'dangerous'. I'd also like to be able to  
pass a block if #something's return evaluates to true.

I've come up with the (monstrous?):

# This allows you to only call a method or block on something that is  
true.
class Object
   # calls method or yields block if self
   def if_so(method=nil, *args, &block)
     if self
       block_given? ? yield(self) : self.send(method.to_sym, args)
     end
   end
end

Any suggestion how this is done better, or any discussion that you  
don't want/need this is appreciated.

Cheers, Bastiaan