From: "Bill Guindon" <agorilla / gmail.com>
>
> I've always wondered about the "return nil if unchanged".  I don't
> believe I've ever used it, but I'm sure I've bumped into it a few
> times where I didn't want to.
> 
> How often is this used/useful?  I can see using it as part of an 'if'
> statement, just can't think of why I would.
> 
> Anybody out there using the nil return on a regular basis?  To the
> point that it's worth sacrificing chaining?

I've only used it occasionally.  But as Matz pointed out
awhile back,
http://ruby-talk.org/cgi-bin/scat.rb/ruby/ruby-talk/17764
if you do need to know whether the object was modified, 
there's no other way to get that information as cheaply.


Regards,

Bill