Re: [Boost-users] Flyweight: wrapping shared_ptr

Subject: Re: [Boost-users] Flyweight: wrapping shared_ptr
From: Joaquin M Lopez Munoz (joaquin_at_[hidden])
Date: 2014-10-08 10:29:44

Akim Demaille <akim <at> lrde.epita.fr> writes:

> 
> Le 8 oct. 2014 à 15:41, Joaquin M Lopez Munoz <joaquin <at> tid.es> a écrit :
> 
> > Joaquin M Lopez Munoz <joaquin <at> tid.es> writes:
> > 
> >> With pointer-like semantics, you have
> >> 
> >> flyweight<foo> f;
> >> flyweight<foo*> g;
> >> 
> >> f->x=0; // OK
> >> g->x=0; // error
> >
> > [...]
> > 
> > std::cout<<f->x;
> > std::cout<<g->x;
> > 
> > for instance. You get the idea, anyway.
> 
> Yes, I think this time I see what you mean.  You're proposing
> 
>   boost::flyweight<std::string> s("foo");
>   std::cerr << s->size() << std::endl;
> 
> to make sense, right?

Correct. Pointer semantics and pass-thru semantics cannot coexist in the
same interface (not that I'm currently considering supporting either,
anyway). For your case this is not a problemm, since you'll be using
some incarnation of your custom poly_flyweight, which you can endow with
whatever -> semantics you like (pass-thru, I presume).

Joaquín M López Muñoz
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