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From: Brad Moore <brad.moore@shaw.ca>
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Subject: Re: Strange error
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Date: 2015-01-24T06:14:15-07:00
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On 15-01-23 06:34 PM, Bob Duff wrote:
> "Randy Brukardt" <randy@rrsoftware.com> writes:
>
>> "Laurent" <daemon2@internet.lu> wrote in message
>> news:3fa7d4c4-f9fe-4d00-9034-a348802087a9@googlegroups.com...
>> ...
>>> How do you professionals prevent such stupid errors? I am just a noob and
>>> playing
>>> a bit around so it has no impact on anything.
>>
>> You don't (or at least, I don't). I seem to write loops that don't loop
>> (forgot the P := P.Next) all the time.
>
> "don't loop"?  That loops too much.  ;-)
>
> I tend to write the boilerplate first:
>
>      while P /= null loop
>
>          P := P.Next;
>      end loop;
>
> Then go back and fill in the body of the loop.  So I don't usually
> make that particural mistake.  Anyway, I think GNAT will give a warning
> about that.
>
> But in Ada 2012, we have iterators, which largely solves the problem.
> Put all your eggs in one basket, and if the iterator works, then all
> the myriad "for" loops around the code will work.

Or in Ada 2005, you can use the Iterate primitive of the containers. 
Then you don't need to write that boilerplate either, as it is already 
done for you. Given the choice though, Ada 2012 iterators provides the 
preferred approach.

Brad