Re: Preventing private procedure visibility being made public through extension

[Jere <jhb.chat@gmail.com>]

On Saturday, May 20, 2017 at 6:51:43 PM UTC-4, Jere wrote:
> On Saturday, May 20, 2017 at 4:32:07 PM UTC-4, Dmitry A. Kazakov wrote:
> > On 2017-05-20 19:33, Jere wrote:
> > > Is there a way for me to prevent extending types from making
> > > the procedure public again?
> > 
> > It is public. That was the decision made in the package Base. The 
> > package Derived has no say on that.
> > 
> > ----------------------------------
> > The actual problem you have is parallel types hierarchies. You want to 
> > derive tied instances of Base_Type'Class and Base_Param'Class.
> > 
> >     Base_Type ----- Base_Param
> >        |              |
> >     Derived_Type -- Derived_Param
> > 
> The actual use case is Gnoga.  All of the constructors
> (the Create procedures) require parent to be of type
> Gnoga.Gui.Base.Base_Type'Class, but I really want my
> Dialog_Type constructor to only accept parents of type
> Gnoga.Gui.Window.Window_Type'Class.  But it also has
> to publicly extend Gnoga.Gui.Base.Base_Type 
> (or I use Gnoga.Gui.View.View_Base_Type) so that
> other controls can create themselves in it.  This
> opens my type and types that extend it to being
> thrashed by calls to Create_From_HTML and so on.
> Similar to your suggestion, I can override them and
> raise an exception...it just feels clunky.
> 
Or perhaps if Ada supported constructors that were not 
dispatchable and that were not inherited that might
also work.  I would need to think about it a bit
to be sure about that though.  Just an off the cuff
thought.