Question

I’d like to add a method to Ruby’s Object to reassigns the value associated with it.

For instance, if I had two strings, I could call my method on one of them so that the pointer to the underlying char[] would point to the other’s underlying char[].

a = object_a
b = object_b
a == object_b #=> false
a.my_method(object_b)
a == object_b #=> true

Can anyone see a way to accomplish this?

Answer 1

You can’t change self, it always points to current object. You can, however, make a proxy around the object. This is quite simple in ruby using SimpleDelegator from the standard library:

require 'delegate'

a = SimpleDelegator.new 'foo'
b = 'bar'
a == b # false
a.__setobj__(b)
a == b # true

You can alias __setobj__ to something nicer, for example:

require 'delegate'

class AwesomeDelegator < SimpleDelegator
  alias_method :become, :__setobj__
end 

a = AwesomeDelegator.new 'foo'
...
a.become('bar')