From: "s.ross" <cwdinfo@...>
Date: 2008-04-05T13:38:42+09:00
Subject: Re: The ||= assignment operator

On Apr 4, 2008, at 8:53 PM, Avdi Grimm wrote:

> On this topic, am I the only one who would really like to see a
> dedicated "defaulting operator" in Ruby?  Something that actually has
> the semantics which a lot of people mistakenly assume for ||=, i.e.
> "assign if and only if nil"?  I think Perl6 uses the //= operator for
> this.  This is such a subtle gotcha.  I've seen a lot of code that was
> potentially buggy because it didn't account for the fact that the
> 'false' value would be handled incorrectly.
>
> --
> Avdi

This would be great, but you would need both a // and //= operator.  
Consider this:

@my_web_page_title = @page_name || "d'oh! you forgot to name your page"

You would want to rewrite this as:

@my_web_page_title = @page_name // "d'oh! you forgot to name your page"

It would seem that adding these operators has a low potential to  
introduce bugs into working code and, as you point out, there are  
subtleties WRT the ||= idiom. Moving it from idiom to first-class  
operator might clarify those subtleties.