From: "list. rb" <list.rb@...>
Date: 2008-10-04T10:05:38+09:00
Subject: Re: Is Assignment in a Conditional an Idiom?

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On Fri, Oct 3, 2008 at 4:36 PM, David A. Black <dblack@rubypal.com> wrote:

> Hi --
>
> On Sat, 4 Oct 2008, List.rb wrote:
>
>  I just figured ruby was looking at the value of a returned from the
>> definition in the condition. The value of  'a' is still false after the
>> second condition.
>>
>
> Are you talking about this one?
>
>  puts "Never reached" unless (a = nil) || (!a = a)
>
> It's a peculiar line of code, but it's entirely logical. The
> expression !a = a has to mean !(a = a), because !a isn't an lvalue.
> Since a is nil, the expression a = a (or x = a, etc.) evaluates to
> nil. So you've basically got:
>
>  unless nil || nil
>
> I might be misunderstanding the part you thought was questionable in
> its logic.
>
>
>
> David
>
> --
> Rails training from David A. Black and Ruby Power and Light:
>  Intro to Ruby on Rails  January 12-15   Fort Lauderdale, FL
>  Advancing with Rails    January 19-22   Fort Lauderdale, FL *
>  * Co-taught with Patrick Ewing!
> See http://www.rubypal.com for details and updates!
>
>
It was late, sorry. I have no idea what I was thinking.

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