Re: Visibility of Indexing aspects

[Shark8 <onewingedshark@gmail.com>]

On Wednesday, July 25, 2018 at 6:12:24 PM UTC-6, Randy Brukardt wrote:
> "Dan'l Miller" wrote in message 
> news:googlegroups.com...
> On Wednesday, July 25, 2018 at 2:58:44 PM UTC-5, AdaMagica wrote:
> >> Much ado about nothing.
> >>
> >> The writer of this code erroneously put things in the private part which
> >> should have been public. There is a compiler bug leaking from privacy
> >>which seduced the writer into thinking that his wrong code is correct.
> >>
> >> The RM is very precise about this, see the references in this thread.
> >>
> >> Love's Labours Lost with any further discussion.
> >
> >In other words, I made an insightful good point ...
> 
> Sounds like babble to me. What's used by the client has to be public, 
> period.

But this is legal:

Package K is
  Type Example is private;
Private
  Type Example is null record;
  For Example'Size use 4;
End K;

Package J is
  Type Hex is range 16#0#..16#F#
  with Size => 4;
   
  Type Ex_2 is record
    Item_1 : Hex;
    Item_2 : K.Example;
  end record
  with Size => 8;

End J;

> ...
> >The _LRM_'s forcing of {Reference, Reference_Holder, Container_Array, ...} 
> >to be public declarations ...
> 
> ...is perfectly fine -- there's nothing wrong or dangerous with using them 
> directly. Indeed, "indexing" is just a shorthand for a longer call involving 
> Reference -- you're always allowed to make the longer call, just like you 
> are allowed to put in .all even if you could have omitted it. We went to 
> substantial lengths to ensure that you can't keep a reference value longer 
> than the existence of the return object from Reference -- regardless of how 
> you use the package. (Telling people not to do something is never an 
> effective technique for safety!)

But that's not the issue that is being cited in the original post.
The issue is that all the indexing-attributes are declared/used in the private part and are [apparently] being used in the publicly visible part.

Is this correct?
Arguments could be made in either direction:
(for-allowing) This allows the public declaration to be kept clean of generally non-relevant details; much like declaring stream input/output functions needn't be made explicitly public to work (due to the stream attributes being accessable).
(for-disallowing) The indexable interface may not be intended for use outside of the PRIVATE visibility space (BODY, children's private, children's body).