Re: How to declare a generic formal type "covered" by another?

[Jeffrey Carter <spam.jrcarter.not@spam.not.acm.org>]

On 05/02/2014 12:58 AM, AdaMagica wrote:
>> Most smart-pointer packages expose the access type; see, for example,
>>
>> http://www.oopweb.com/Ada/Documents/AdaLinux/Volume/18.html
>> http://www.adacore.com/adaanswers/gems/gem-97-reference-counting-in-ada-part-1/
>
> But exposing the access type is bad since pointes may easily outlive the object they point to.

The point is not that it's good, but that it appears to be necessary to get 
around the kind of problems the OP is dealing with.

One can create a safe-pointer package that does not expose an access type (see 
the PragmAda Reusable Components for an example), but the result tends to be 
restricted to pointers to definite, non-limited types.

-- 
Jeff Carter
"I was hobbling along, minding my own business, all of a
sudden, up he comes, cures me! One minute I'm a leper with
a trade, next minute my livelihood's gone! Not so much as a
'by your leave!' You're cured, mate. Bloody do-gooder!"
Monty Python's Life of Brian
76