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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Operation can be dispatching in only one type
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Date: Fri, 4 Dec 2009 09:52:18 +0100
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Date: 2009-12-04T09:52:18+01:00
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On Thu, 3 Dec 2009 17:08:01 -0600, Randy Brukardt wrote:

> It should be noted that our local coding standard would consider the above 
> incorrect; there always must be an else branch or at least a comment 
> explaining why there is no else branch:

What about:

   if Read_Error (File) then
      raise Data_Error;
   end if;

or

   if Estimated_Error <= Threshold then
      return Estimated_Result;
   end if;

or "exit when", which is a hidden if without else.

All these cases represent some lengthy action, maybe iterated or recursive.
The action is left upon some condition.

If not senseless "else null;", then semantically, under "else" there must
be the rest of the action (recursive, infinite).

Maybe "if" with two alternatives should better be "case". Though it would
look strange most of us:

   case Condition is
      when True =>
         X := This;
      when False =>
         X := That;
   end case;

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