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Newsgroups: comp.lang.ada
Date: Thu, 31 Dec 2020 04:57:28 -0800 (PST)
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Subject: Re: Question on variant/discriminated records
From: reinert <reinkor@gmail.com>
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Approaching :-) But the interpretation of (the meaning of) r.y could in principle be 
calculated on the fly (when called) based on the received discriminant -
but arguments related to  security/reliability  are against?

Maybe nice to find errors at compile time as compared to experiencing costly runtime errors :-)

reinert

torsdag 31. desember 2020 kl. 13:46:47 UTC+1 skrev gautier:
> On Thursday, December 31, 2020 at 1:24:25 PM UTC+1, reinert wrote: 
> > Here must be a hole in my understanding. I thought that the discriminant must be known 
> > before V.Y := 1.0; and hence there should be no confusion?
> Imagine you have a function Evaluate (r : rec1_Type) return Float. 
> Except in trivial cases like 
> if r.option1 = b then result := result + r.y; end if; 
> the compiler cannot guess the value of the discriminant.