From: ben@...
Date: 2006-06-23T13:45:40+09:00
Subject: Quick singleton question

Hi,

In a structure I'm building, I need to be able to add children (of the same
class) to an object, and have the child object know who its parent is. So I
can do obj.instance_variable_set(:@parent,parentobj), but that doesn't
create the accessor for me, so I still need to do

class << child
    def parent
        @parent
    end
end

That's not really all that onerous, and I can always predefine attr_reader
for :parent in the main class to save the second step, but it lead me to
wondering if there is a 'nice' way to add an instance variable and its
accessor all at once to an object, because that will probably come in handy
one day.

Initially I wanted to do

class << child
    def parent
        parentobj
    end
end

but obviously that will fail since parentobj is out of scope.

Anyway, that's it. :)

ben