From: Stefano Crocco <stefano.crocco@...>
Date: 2008-04-06T01:04:50+09:00
Subject: Re: The ||= assignment operator

On Saturday 05 April 2008, Brian Adkins wrote:
> On Apr 5, 8:40 am, "David A. Black" <dbl...@rubypal.com> wrote:
> > Hi --
> >
> > On Sat, 5 Apr 2008, Robert Dober wrote:
> > > Furthermore things are simple
> > >
> > > (1) lval ||= rval  is lval = lval || rval
> >
> > I think you mean:
> >
> >    lval || lval = rval
>
> Huh?
>
> My understanding has always been that x ||= y is shorthand for x = x
>
> || y just as x += y is shorthand for x = x + y. That also seems to be
>
> the understanding of the "Programming Ruby" text (p. 125 of the
> latest). In other words, an assignment will take place even if it's
> superfluous.

I also thought so, but, according to "The ruby programming language", it's an 
exception. It states that, if the left hand of var ||= something is not nil or 
false, no assignment is performed and, if the left hand is an array element or 
attribute, the setter method is not called.

Stefano+