[boost] Re: Re: Re: Re: move_ptr

From: Jonathan Turkanis (technews_at_[hidden])
Date: 2004-01-21 19:30:26

"Daniel Wallin" <dalwan01_at_[hidden]> wrote in message
news:400F1267.8090002_at_student.umu.se...
> Jonathan Turkanis wrote:
>

> > First, I'm just proposing the policy parameter so we will have a
> > number of options to choose from. Right now, there isn't any
client
> > code to break.
>
> Yes I am aware of that, and what I'm saying is that we should be
> careful about complicating things too much.
>
> > Second, it shouldn't break any code, if people agree with you and
> > don't want custom deleters:
> >
> >     template< typename T,
> >                     template<typename> class Deletion = no_storage
>
> >     class move_ptr;
> >
> > (I've made the policy into a template template parameter, for
> > convenience.)
>
> You almost certainly don't want this. If you need to generate the
> deleter type somehow, make it a metafunction class.

I stay away from template template parameters most of the time, for
the sake of old compilers. But here we're relying heavily on SFINAE,
so I don't see the need. In one of my earlier posts the policies were
(implicitly) metafunction classes, but when I actually sat down to
write them it seemed to make the code needlessly obscure. I'm trying
to be careful not to complicate things too much ;-). Its no big deal
to switch later.

>
> > People who agree with you will just use plain move_ptr<T>, so
their
> > code won't be affected. People who like and use custom deleters
will
> > argue against the removal of the policy parameter.
>
> Again, the point is that if we were to get to a point where people
use
> custom deleters it's (almost) too late to remove them, regardless of
how
> bad a design choice they turn out to be.
>

I think it's reasonable to create a prototype so people can see an
example of what they're arguing about. My goal is to have the
implementation done tonight. That means it will be done next week. :-)
People can play with it a bit --  if they're interested -- and let me
know what they think. Maybe by next Tuesday there will be a consensus
to scrap the deleters.

I think it's a little early in the game to be worrying that it will
soon be 'too late' to remove features.

Jonathan