Re: Quick singleton question

> -----Original Message-----
> From: David Pollak [mailto:[e-mail]]
> Sent: Friday, June 23, 2006 12:10 PM
> To: ruby-talk ML
> Subject: Re: Quick singleton question
>
> Ben,
>
> Try:
> class Dude
>   attr parent
>   attr kids
>
>   def initialize(parent)
>     @parent = parent
>     @kids = []
>     parent.add_kid(self) unless parent.nil?
>   end
>
>   def do_something_in_the_tree(depth = 0, &block)
>     @kids.each {|kid| kid.do_something_in_the_tree(depth + 1, &block)}
>     block.call(self, depth)
>   end
>
>   protected
>   def add_kid(the_kid)
>     @kids << the_kid
>   end
> end
>
> Kids know their parent.  Parents know their kids.  I threw in a way to
> recursively walk the tree... so you can do something like:
> root.do_something_in_the_tree {|node, depth| puts "#{'
> '*depth}#{node}" }
>
> Thanks,
>
> David

Hi David,

I was actually fishing for the best way to add the instance_variable and
accessor at runtime in case I need it another day, but your code below is
nicer than mine for this particular static class, thanks a lot. I was using
a child array and instance_variable_set in add_child (by default assume no
parent) whereas you're assuming a parent param to initialize by default,
which is probably cleaner. I especially like the recursive tree-walk that
takes a block. Thanks. :)

Cheers,

ben