Re: Parameterised 'Image Attributes

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

On 2023-09-07 03:04, Randy Brukardt wrote:
> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message
> news:uchukd$1lnvp$1@dont-email.me...
>> On 2023-08-28 11:18, Stephen Davies wrote:
>>
> ...
>> Neither there is one why 'Image must be a non-overridable attribute
> 
> There actually is a good reason for this. Attributes have global visibility.
> So if you allowed overriding of attributes, then a with added or removed in
> a remote part of a program could silently change the behavior of code that
> has no knowledge of of the change. That would be bad for "programming in the
> large". Note that Ada 95 was proven to have no such cases, and we've tried
> very hard to avoid them.

Ah, but 'Image is for debugging only! (:-))

> One could imagine adding rather severe restrictions to overriding of
> attributes to eliminate this problem (for instance, only allowing it for
> primitive operations of the type), but that would eliminate all real value
> of the feature (you can always use a primitive function and "use all" to get
> the same effect without any new features).

It must be a new type:

    type My_Integer is new Integer;
    for My_Integer'Image use Foo;

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