Re: Boeing and Dreamliner

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

On Tue, 01 Jul 2003 05:31:20 GMT, Hyman Rosen <hyrosen@mail.com>
wrote:

>Richard Riehle wrote:
> > In C++ it is perfectly legal to do all kinds of assignment statements
> > where the result is not entirely predictable.
>
>I'm not sure what you mean by this. If you're talking about order
>of evaluation, Ada has the same lack of predictability, although
>Java does not.
>
>> A key difference between Ada and many other languages is
>> the absence of structural equivalence in favor of named equivalence.
>
>Again, I don't know how this applies to C++, except for one case I
>can think of - a union with record members all of which share the
>identical set of leading fields. X Window uses this feature to allow
>access to the type of an event.

Another example is pointers. They are matched by structure not by
names. In Ada different pointer types are different even if they point
to objects of same type. It might look strange from C++ point of view,
but sometimes it is very useful (consider storage pools, for example).

However, it seems impossible to drop structured equivalence
completely. So even in Ada there are anonymous access types, array
types, ranges, T'Class etc, all matched by structure.

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