Re: Limited use for limited with?

[Adam Beneschan <adam@irvine.com>]

On Sep 30, 12:27 am, Stephen Leake <stephen_le...@stephe-leake.org>
wrote:
> Ludovic Brenta <ludo...@ludovic-brenta.org> writes:
> > I generally think twice or three times before declaring an access type
> > in the same package as the object type. In fact, I think twice before
> > declaring any access type at all :) To me, an access type makes the
> > package unclean.
>
> > Since, in Ada, all objects of tagged types are passed by reference and
> > since Ada has class-wide types, you do not need any access type to
> > achieve pass-by-reference semantics or dynamic dispatching. This
> > leaves dynamic memory allocation as the only remaining justification
> > for access types.
>
> You left out accessibility checks, which are an important reason for
> named access types.

Really?  Most uses of anonymous access types still involve
accessibility checks.  The main case where they don't is access
parameters; and in that case, you usually don't want accessibility
checks unless you're going to store the parameter somewhere where it
could live after the subprogram is completed, and doing so is going to
involve an accessibility check at the point where it's stored, whether
or not the type of the stored data is named or anonymous.  This should
all be crystal clear from reading 3.10.2.

(I'm kidding about that last.  Nothing about 3.10.2 is clear.  The
only reason I recommend reading 3.10.2 is because I own stock in
Advil.)

                                      -- Adam