Re: Preventing type extensions

[Cyrille <comar@eu.adacore.com>]

On Sep 22, 10:01 am, "J-P. Rosen" <ro...@adalog.fr> wrote:
> Ada is unique in that you can have true methods (aka primitive
> operations) that belong to a specific type, and class-wide operations
> that are unique for a whole subtree.

what is unique about that? In C++ you also have methods and other
subprograms taking a class as a parameter. I don't see any fundamental
difference between the latter and what you call "classwide
operations" (and by which I suppose you simply mean a subprogram with
classwide parameters, right?)

> Because they are unique, coverage testing drops from N to 1.

No idea of what you are talking about... I suppose this is a reference
to what OOTiA calls "pessimistic testing" but I still don't understand
your claim.

> >> For inlining, I was referring to the corresponding chapter of OOTiA
>
> > That's what I supposed.... There is little to be reused in that part
> > of the document...
>
> I agree that there is nothing here specific to OO. However, inlining is
> a problem when you need level A (code) coverage, because it creates
> often dead code or hard to test paths.

Level A requires statements+mcdc coverage. inlining doesn't impact any
of those coverage metrics. It might impact object coverage, which can
be used as an alternative method (with additional work to show
equivalene with the aboce mentioned metrics) and it might also impact
source-to-object traceability analysis. This is just a potentially
complicating factor that you have to take into account when you make
your plans and define your coding standard...

> > It is not the case. There is very little of OOTiA left in the OO
> > supplement. It was an input to the process but the subcommittee soon
> > realized that little could be reused. For one thing, most of the
> > material is at the level of "coding standard" material and thus not at
> > the right level for a standard such as DO-178.
>
> Sure. I would expect DO-178C to be more objectives-driven, while the
> OOTiA was more about processes and issues. Can't OOTiA be considered as
> a document that explores possible ways to achieve the objectives of DO-178C?

not really. OOTiA raised all the issues that people had in mind when
the document was written. Most of the issues come from either
   - people from the certif community not knowing OO very well (the
fear factor)
   - people from the OO community not mastering DO-178