Re: Ada.Locales pseudo-string types

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

On Wed, 08 Aug 2012 14:52:01 +0300, Niklas Holsti wrote:

> On 12-08-08 11:35 , Dmitry A. Kazakov wrote:
>> On Wed, 08 Aug 2012 11:17:46 +0300, Niklas Holsti wrote:
>> 
>>> For value conversions, including "in" parameters, the exact match could
>>> be replaced by a static check that the constraints on the source
>>> elements are the same as or stronger than those on the target elements.
>>> This would allow Ada.Text_IO.Put (String (Some_Country_Code)).
>>>
>>> For "out" parameters, there could be a static check that the constraints
>>> on the actual (source) array elements are the same as or weaker than
>>> those on the formal (target) array elements.
>>>
>>> For "in out" parameters, the present static-match rule would be kept, as
>>> the logical conjunction of the "in" and "out" rules.
>> 
>> 1. You cannot check that statically because the constraint of the subtype
>> can be dynamic.
> 
> I meant (of course!) that the conversion would be allowed only if the
> strengths of the constraints can be checked statically, using similar
> kinds of rules as are now used for "statically matching" subtypes and
> constraints. In effect, the bounds of the ranges would have to match
> exactly, or be static expressions with values in the necessary order
> relationships.

Well, that could work. However error messages would be quite annoying when
something turns to be not so static as it appears.

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