Re: Legit Warnings or not

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

On Fri, 22 Jul 2011 19:36:26 -0500, Randy Brukardt wrote:

> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message 
> news:1rx6dwrxmc81p.eazb4fjqztox$.dlg@40tude.net...
> ...
>> I think that Ada should not try to support this stuff.
> 
> Ada *does* support this stuff. As Adam noted, there are rules preventing the 
> creation of accesses/renames of/into components that might change size.

But it should not. Programmers expect types constructed by the compiler be
contiguous in their private view.

> There also are rules supporting allocation/deallocation of objects that have 
> multiple parts. So far as I know, those are the only rules needed to do so.

Meaningful X'Size? Expectations in an implementation of
Ada.Finalization.Adjust?

> There also are rules supporting allocation/deallocation of objects that have 
> multiple parts. So far as I know, those are the only rules needed to do so.

E.g. in a user-defined specific pool?

> And, as noted, Janus/Ada always has worked this way. I originally thought 
> Ada compilers were expected to work this way, because there is no good 
> reason not to support this as the default (as noted, some target 
> environments might not want such objects, and pragma Restrictions can surely 
> be used to prevent them from being generated). But apparently, implementers 
> are lazy enough to avoid it, and customers have never pushed hard enough to 
> get it added as an option.

As a customer I see that the language separates definite and indefinite
types. If this distinction is necessary, then the same logic applies to the
implementation. I prefer transparent and simple implementations in order to
know what to expect. In cases where I need referential semantics I prefer
to implement it by myself, rather than to rely on the compiler.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de