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From: Ray Blaak <blaak@vault86.infomatch.bc.ca>
Subject: Re: Software landmines (loops)
Date: 1998/09/04
Message-ID: <m3pvdcb45j.fsf@vault86.infomatch.bc.ca>#1/1
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Organization: BCTEL Advanced Communications
Newsgroups: comp.lang.eiffel,comp.object,comp.software-eng,comp.lang.ada
Date: 1998-09-04T00:00:00+00:00
List-Id: <comp.lang.ada>

"Robert Martin" <rmartin@oma.com> writes:
> It seems to me that:
> 
>  if (A is right)
>    if (B is right)
>      if (C is right)
>         then do the work.
> 
> emphasizes the work more than:
> 
> if (A is wrong) then return;
> if (B is wrong) then return;
> if (C is wrong) then return;
> do the work;
> 

A compromise that allows both positive logic and reduced nesting is to
calculate a guard value, and only do the work if the guard is true:

  doit := (A is right);
  doit := doit and (B is right);
  doit := doit and (C is right);
  if doit then do the work;

-- 
Cheers,                                        The Rhythm is around me,
                                               The Rhythm has control.
Ray Blaak                                      The Rhythm is inside me,
blaak@infomatch.com                            The Rhythm has my soul.