Re: The Ravenscar profile and capabilities paradigm

[Shark8 <onewingedshark@gmail.com>]

On Tuesday, October 12, 2021 at 9:04:09 AM UTC-6, Luke A. Guest wrote:
> On 12/10/2021 16:01, Shark8 wrote: 
> > On Monday, October 11, 2021 at 1:24:48 PM UTC-6, Doctor Who wrote: 
> >> On Mon, 11 Oct 2021 16:32:13 +0100, Simon Wright wrote: 
> >>> Doctor Who writes: 
> >>> 
> >>>> someone knows how to introduce the capabilities paradigm in Ada, 
> >>>> specifically for programs written using the Ravenscar profile ? 
> >>>
> > Type Capability is ( Read, Copy, Whatever );
> There can be a capabiity for literally anything, even ownership and can 
> be different depending on object/os service. 
> 
> I'd say a tagged type is better than an enum.
Possibly.
But there's no reason to complicate the general idea in example-form: even if it's a tagged type you're going to want the capability-instance to be limited-private; the implementation of the "permissions" component being a Boolean-array or a vector of Capability'Class [most obviously having Capability be an abstract tagged null record] is mostly irrelevant for that demonstration. (And using a vector of tagged-type instead of the array would have bogged the example down with importing and instantiating the Vector container and setting up multiple non-abstract Capability-descendants, cluttering the point of the example.)