Re: non record limited type

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

On 23/02/2018 00:24, Randy Brukardt wrote:
> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message
> news:p6luqm$jb1$1@gioia.aioe.org...
>> On 22/02/2018 02:29, Randy Brukardt wrote:
>>
>>> These types that become limited just because of "limited private" also
>>> have
>>> the nasty property of becoming non-limited when you can see the full
>>> declaration. This causes all kinds of semantic complications that we'd
>>> rather not repeat, so everything new requires declaring it limited
>>> explicitly and staying that way.
>>
>> I don't see anything wrong with that, except for coupling to by-reference
>> semantics. On/off visibility of the copying operation is all OK, it is
>> just an operation. Parameter passing method is a different thing.
> 
> Not to Ada: by-copy uses the assignment operation (which isn't quite the
> same thing as :=). Limited assignment is build-in-place only (for
> initialization purposes, another rule I know you hate). Probably could be
> different, but it would take extra work, and so far, there doesn't seem to
> be much need.

Right, but by-copy passing is not really assignment. It is a 
copy-constructor. When assignment finalizes the target, copy-constructor 
does not do anything. Ideally we should be able to disable ":=" while 
keeping by-copy passing. I can imagine use cases for short-lived smart 
pointers and iterators where I wanted no explicit copies made.

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