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Newsgroups: comp.lang.ada
Date: Tue, 19 Apr 2016 15:40:38 -0700 (PDT)
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Subject: Re: if-then-no-else  Programming
From: Shark8 <onewingedshark@gmail.com>
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Xref: news.eternal-september.org comp.lang.ada:30202
Date: 2016-04-19T15:40:38-07:00
List-Id: <comp.lang.ada>

On Tuesday, April 19, 2016 at 1:51:07 PM UTC-6, Randy Brukardt wrote:
> 
> Indeed, RRS has a style rule which is the exact opposite of his suggestion. 
> We require either an else or a comment that no else is needed for most if 
> statements. We found that we had cases like:
> 
>     if condition then
>          Do_Something;
>     end if;
> 
> and there would be a bug because nothing was done if condition was False. 
> Errors of omission are the hardest things to find, and we hoped to reduce 
> the number of them by at least requiring the programmer to think about all 
> of the possibilities and documenting that they did so. Thus, the above would 
> have to be written:
> 
>     if condition then
>          Do_Something;
>     -- else nothing needed.
>     end if;
> 
> so it's obvious that the reverse condition was considered.

But we can do this natively in Ada:

if condition then
  Do_Something;
else
  null; -- Nothing needed.
end if;

I would think that there would be zero difference in code generation between that and w/o the else.