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From: Niklas Holsti <niklas.holsti@tidorum.invalid>
Newsgroups: comp.lang.ada
Subject: Re: GNAT 4.4.5 order of conditional processing?
Date: Tue, 15 Nov 2011 21:54:59 +0100
Organization: Tidorum Ltd
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Date: 2011-11-15T21:54:59+01:00
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On 11-11-15 21:30 , awdorrin wrote:
> Given an IF statement such as the following:
>
> if X = Y and not A and B
>
> How does GNAT handle the processing of the conditional statements?
> Will "X = Y" be processed first, and if false, will the rest be
> skipped?

If you want to be sure that the later conjuncts are evaluated only if 
X=Y, use the "and then" form. The following first evaluates "X = Y", and 
then evaluates "not A and B" only if X = Y:

    if X = Y and then (not A and B) then
       do something
    end if;

Or, expand also the later "and" so that B is evaluated only if X = Y and 
A is false:

    if X = Y and then (not A) and then B then
       do something
    end if;

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
       .      @       .