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From: Peter Amey <peter.amey@praxis-cs.co.uk>
Newsgroups: comp.lang.ada
Subject: Re: In-Out Parameters for functions
Date: Tue, 27 Jan 2004 09:23:42 +0000
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Interesting sub thread.  It has raised all the nastiness of function 
side effects, evaluation order dependency and aliasing.  FWIW, avoiding 
these kinds of issue were a major motivator in the design of SPARK. 
SPARK functions never have side effects, the language is free from 
evaluation order dependencies and aliasing is efficiently detected in 
all cases.  These steps, in our opinion, are a necessary precondition 
for rigorous static analysis.

regards

Peter

Alexandre E. Kopilovitch wrote:
> Wojtek Narczynski wrote:
> 
> 
>>This worry is unclear to me:
>>
>>
>>>>And only one seems still valid: it is about complex 
>>>>expressions where a function call may be used as 
>>>>an actual argument for another function. 
>>
>>I don't see how adding IN OUT arguments could make things worse in
>>this matter.
> 
> 
> Look at this formulae:
> 
>   F(A) + G(A);
> 
> [snip]