[BLACKBOX] AW: [BLACKBOX] Discussing IN is not 'Wasting time'

From: Zinn, Helmut <"Zinn,>
Date: Tue, 26 Feb 2008 13:08:45 +0100

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Dear Chris,

> In both cases, the change made to the global value of a.i persists
after
> exit from the procedure.

> Unfortunately, IN parameters only make pointers marginally less risky
than
> they are already. Working with pointers is like working with reals.
The
> programmer needs to have a real good understanding of what they are
doing.

I'm sorry, I don't agree. Expansion of the language should be done very
carefully.

OM introduced IN for ARRAYs and RECORDs variable only. They define that
IN variables are constant and it is not allowing to change their
contents.

Now you would like to extend the use of IN for other variables including
pointers too.

Why should not keep the same rule? Why are not going to go the save way?
Everybody who is reading the program source expects that IN variables
are unchanged.

You can pass pointer variable without IN and you have the possibility to
change their contents there without changing the pointer itself as you
described above (backward compatibility).

Regards,

Helmut Zinn

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Received on Tue Feb 26 2008 - 13:08:45 UTC