From: Pit Capitain <pit.capitain@...>
Date: 2008-05-03T01:12:07+09:00
Subject: Re: Please explain nuances of ||=

2008/5/2 Rick DeNatale <rick.denatale@gmail.com>:
>  3) I say first approximations because of David Black's observation
>  that x ||= y and x || x = y differ when x is undefined.

They obviously also differ if evaluating x has side effects as in

  h = {}
  h[print("f")] ||= 1

  h = {}
  h[print("o")] || h[print("o")] = 1

  # => foo

so x ||= y is more like

  ref = &x; *ref || *ref = y

with the reference (&) and dereference (*) operators of C.

Regards,
Pit