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Newsgroups: comp.lang.ada
Date: Fri, 3 Jul 2015 19:02:44 -0700 (PDT)
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Subject: Re: How best to test for NULL in Ada?
From: Shark8 <onewingedshark@gmail.com>
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Xref: number.nntp.giganews.com comp.lang.ada:193904
Date: 2015-07-03T19:02:44-07:00
List-Id: <comp.lang.ada>

On Thursday, July 2, 2015 at 6:12:53 PM UTC-6, Randy Brukardt wrote:
>
> In Ada 2012 there is a hack available to avoid the use clause. (This comes 
> from Tucker Taft, who admitted to doing this during our recent ARG meeting 
> in Madrid. He got suitable groans for this usage...)
> 
>     if Some_Object not in null then
> 
> This membership uses the predefined equality for the type of Some_Object, 
> and it need not be visible. But this is a hack (it harms readability), and 
> it's dangerous if "=" has been redefined (as it always uses the predefined 
> "=", not the overridden one). Use at your own risk.

Hm I can see where, if you were writing your own "=" operator for Some_Object's type and it was (a) an access type, and (b) you needed to test for null that could be useful.