Re: Ada to 'C' parameter passing problem

[Dmitry A. Kazakov <mailbox@dmitry-kazakov.de>]

On 20 Feb 2003 01:18:34 -0800, rod.chapman@praxis-cs.co.uk (Rod
Chapman) wrote:

>mheaney@on2.com (Matthew Heaney) wrote in message news:> That Ada doesn't allow you to specify inout mode for function
>> parameters is a deficiency of Ada...
>
>Wow!  This reflects somewhat of a gulf between our respective
>views of language design!  (Don't get me wrong, neither position
>is necessarily right or wrong, just different...)
>
>At the SPARK end of the spectrum functions calls are expressions
>which return a value and never have a side-effect.  Procedure
>calls are statements which have side-effects - A rather
>significant _semantic_ difference!
>
>If you do prefer the ability to allow a function to modify its
>parameters, then it should at least be good enough to confess
>this to the outside-world as part of its specifiction.  The current
>discussion for Ada0Y in AI231 (extending anonymous access
>parameters) is welcome here, especially from a static-analysis
>point of view.

[ Long awaited thread "inout parameters for functions" is again here
(:-)) ]

"To return a value via the result parameter" /= "To have no side
effects other than on the out and inout parameters"

To mix the above two is definitely a deficiency. To involve pointers
as a work-around for consequences of that deficiency is worse than
just a deficiency.

---
Regards,
Dmitry Kazakov
www.dmitry-kazakov.de