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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Depth First Search of a Char_Matrix?
Date: Sat, 27 Apr 2013 20:48:09 +0200
Organization: cbb software GmbH
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Date: 2013-04-27T20:48:09+02:00
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On Sat, 27 Apr 2013 11:16:34 -0700 (PDT), Shark8 wrote:

> On Saturday, April 27, 2013 11:25:57 AM UTC-6, Jeffrey Carter wrote:
>> 
>> There is absolutely no reason to use access types (especially not anonymous 
>> access types) or addresses for this problem.
> 
> Sure, but there's no real reason not to: the illustration was simply a DFS
> on something that might-not-exist and so null/some-object map to that
> perfectly fine.

No, you don't place a key into the map if there is no value for it.

> It's an error to ask "what color is the piece at X,Y?" when the element
> X,Y contains no piece;

Likely

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de