From: Rob Biedenharn <Rob@...>
Date: 2008-06-12T06:23:49+09:00
Subject: Re: ||=


On Jun 11, 2008, at 5:12 PM, Lyle Johnson wrote:

> On Wed, Jun 11, 2008 at 3:59 PM, Justin To <tekmc@hotmail.com> wrote:
>
>> what does ||= do?
>
> The expression:
>
>    x ||= y
>
> is shorthand for:
>
>    x = x || y
>
> where "||" is the OR-operator. If x evaluates as false or nil, the
> value of y will be assigned to x; otherwise, x keeps its original
> value. So, for example,
>
>    x = nil
>    x ||= 42 # now x has value 42
>    x ||= 23 # x stays at 42
>
> Hope this helps,
>
> Lyle
>


Actually, it is like:

   x || x=y

Refer to:
http://dablog.rubypal.com/2008/3/25/a-short-circuit-edge-case

-Rob