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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Why is the destructor called multiple times after I declare an
 object?
Date: Thu, 14 Jan 2016 14:42:53 +0100
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Date: 2016-01-14T14:42:53+01:00
List-Id: <comp.lang.ada>

On 14/01/2016 11:04, Georg Bauhaus wrote:
> On 13.01.16 20:59, Dmitry A. Kazakov wrote:
>> Sure, some object is always returned and every object is always same
>> to itself. This is not sufficient to define useful "in-place". In my
>> view a definition must have the place known at the caller's context.
>> E.g. to have the object:
>>
>> 1. Allocated at a specific machine address
>> 2. Allocated by an allocator in the specific memory pool
>> 3. Allocated as a specific component of a container object
>> 4. Allocated as a parent of a derived type object
>>
>> The problem of returned object is that it conflates allocation with
>> initialization.
>
> If Ada will have a way for the caller to express the placement of new
> objects to be constructed in situ by functions,

By procedures, of course. Initializer must a procedure.

> might we then go back to just
> return-by-reference in the hope of abandoning "return-by-access"?

There is a simpler and cleaner way. What is needed is user-defined 
procedures implementing record/array component read and update access as 
primitive operations. No need to implement the syntax sugar

    X.M := F (...)

literally as two separate evaluations of X.M and F(...) with inventing 
some intermediate objects to pass to some virtual assignment meaningless 
for limited types anyway. It should be

    Set_M (X, ...);

with lots of problems with limited and indefinite types eliminated.

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