Re: Private extension of a synchronized interface

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

On Sunday, February 17, 2019 at 4:50:24 AM UTC-5, Dmitry A. Kazakov wrote:
> 
> But synchronized interfaces are totally bogus from the software design 
> POV. It is a pure implementation aspect exposed. Why do you care? 
> Aggregate a protected object and delegate primitive operations to it.
> 

That's what I am doing as my own solution.  I was intrigued with the code
above as an alternate solution because it could potentially give a 
compile time indication that a procedure was a protected operation (as
opposed to me relying on simply providing that via comments).  A delegate 
non protected procedure has to rely on the comment.  I didn't even want
the interface to use as an interface, just as a means to at the API level
to have a compiler enforced indication that the procedure was from a 
protected object.  I started with a protected object in the public view
but the implementation details of the private part of the protected object
led to about 10 lines of code (type declarations and a couple of package
specifications) that had no use to the public view but had to be there 
because of how protected object declarations work.  I saw this as a potential
means of information hiding.  My actual solution is as you suggested with
delegate operations that call the protected object.  However, I honestly
wanted to know why Ada allowed one to setup the private extension but not 
allow you to actually provide the functions (or if this was a GNAT issue or
if I was just not using the right syntax).  So the reason I care was a
thirst for knowledge of how things work.