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From: Victor Porton <porton@narod.ru>
Newsgroups: comp.lang.ada
Subject: Re: Tell whether a primitive subprogram was overridden
Date: Tue, 19 Aug 2014 02:57:15 +0300
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Date: 2014-08-19T02:57:15+03:00
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Adam Beneschan wrote:

> On Monday, August 18, 2014 4:41:24 PM UTC-7, Victor Porton wrote:
>> Is it possible to determine whether for a given object of type T'Class a
>> primitive subprogram F was overridden (not the same as for type T)?
>> 
>> I would like this check for efficiency reasons, not to pass it to a
>> callback if the default "null" operation was not overridden.
> 
> No, Ada doesn't provide a mechanism for this.  I don't know of a language
> that does, although in some languages you might be able to use
> "reflection" to squeeze the information out, but with some difficulty.
> 
> The best solution that I can think of is to add a function to T:
> 
>     function F_Does_Something_Useful (Obj : T) return boolean;
> 
> This would be False for T, but for any derived type where you override F,
> you'd also override this function to make it return True.

No, I won't add this obscure function F_Does_Something_Useful only to 
increase the speed for a tiny bit.

-- 
Victor Porton - http://portonvictor.org