From: Mark Bush <mark@...>
Date: 2008-03-24T03:30:16+09:00
Subject: Re: Sytem hook for instance names?

Jeff Patterson wrote:
> Is there a system hook that allows a method to get an instance's symbol
> from its' object id?
> 
> i.e.
> 
> a=SomeObject.new
> SomeSystemhook(a) => :a (or "a" I suppose)

The problem is that the variable is not the object, just a pointer to 
it.  And there can be multiple variables pointing to the object.  So:

a = SomeObject.new
b = a

Now "a" and "b" both point to the same object.  How would you choose 
between returning :a and :b?

If you don't mind, then for instance variables you can do something 
like:

def get_instance_variable_symbol_for_object v
  instance_variables.each do |var|
    if value = instance_variable_get(var)
      return var if value.object_id.eql?(v.object_id)
    end
  end
end

Untested.

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