Getting memory address of object into string

[drkameleon]

So, I am creating a new instance of a ref object.

If I do echo repr(obj), I get something like this:
    
    
    ref 0x10ba54390 --> [...object fields...]
    
    
    Run

How can I get this "0x10ba54390" into a string? (I tried with addr, etc - but 
I'm confused...)