Re: [boost] [1.44] Beta progress?

Subject: Re: [boost] [1.44] Beta progress?
From: David Abrahams (dave_at_[hidden])
Date: 2010-07-27 15:31:50

At Tue, 27 Jul 2010 11:58:19 -0800,
Robert Ramey wrote:
> 
> David Abrahams wrote:
> > At Tue, 27 Jul 2010 09:19:53 -0800,
> > Robert Ramey wrote:
> 
> >> First of all - these are serializable types by virtue of
> >> the fact that they are convertible to integers and references
> >> to integers.
> >
> > If you are claiming that convertibility to integers and references to
> > integers is enough to satisfy your Serializable concept, I can almost
> > **guarantee** you that the concept is ill-defined, and that using the
> > Boost Concept Check Library properly would prove it.
> 
> Hmm - that is in fact my claim.  In fact I believe that any
> type implicitly convertible to a c++ primitive type (type and reference)
> is a serializable type.  

> An archive class is required to be able to serialize all
> serializable types - so any archive class has to be able to
> serialize all c++ primitives.

And what is your definition of Serializable (precisely, please)?

> So what am I missing here.

try this example, and see how well your library deals with it.

    struct X
    {
        operator short() const { return 0; }
        operator short&() const  { return 0; }

        operator long() const  { return 0; }
        operator long&() const  { return 0; }
    };

in concept requirements the use of convertibility almost always causes
problems.

> BTW - I just checked the documentation and althoutgh the above is
> what I meant - it doesn't quite say this.  I can easily fix that.

For what it's worth, based on these discussions (and not a recent look
at your docs, admittedly) I _think_ I can identify at least one
problem with your specification and your idea of what is a proper
implementation detail.  Please tell me if I'm wrong:

  You require archives to handle all primitive types, yet there is a
  large class of such types for which you say the interface that
  creates instances, and gets and sets their values, is a private
  implementation detail.

  If I have that right, it means there's no reliable way to get their
  bits into an archive so they can be deserialized with the same
  values they went in with.

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com