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From: Dmitry A. Kazakov <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Out parameters in a function
Date: Fri, 26 Apr 2002 09:32:31 +0200
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Date: 2002-04-26T09:32:31+02:00
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On Wed, 24 Apr 2002 17:21:37 GMT, "Warren W. Gay VE3WWG"
<ve3wwg@home.com> wrote:

>Dmitry A. Kazakov wrote:
>
>> On Tue, 16 Apr 2002 20:00:42 +0000 (UTC), "Kent Paul Dolan"
>> <xanthian@well.com> wrote:
>
>...
>
>> Same in Ada:
>> 
>> declare
>>    aSomestructTypedVariable : constant SomestructType :=
>>       aSomestructReturningFunction (...);
>> begin
>>    if aSomestructTypedVariable.booleanPart then
>>       usefulVal := aSomestructTypedVariable.usefulPart;
>>    end if;
>> end;
>
>You could take this one step further (or perhaps this is implied)
>and make the returned "SomestructType" a discriminated type. That
>way if the value .booleanPart is false, the other member(s) of the
>record/structure is invalid to access, maintaining safety.

Yes, indeed. Safety is a good point. Ada offers many nice
possibilities with that respect. Another is to return a class wide
object with later dispatch on something like Use_That_Stuff.

Regards,
Dmitry Kazakov
www.dmitry-kazakov.de