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From: Rodolfo Lima on 7 Jul 2010 05:11
On Jul 3, 7:50 pm, Rodolfo Lima <rodo...(a)rodsoft.org> wrote:

> In my proposal, in cases where the list's size isn't needed at compile
> time, the partial specialization would be used, making
> initializer_list not dependent on list's size (would be the case for
> std::vector, for instance). Only when I *want* different
> instantiations for different sizes the base template (dependent on
> list's size) would be used. The way I see it is a win-win situation,
> isn't it?

Does anyone think that this might be a solution to the problem of
constexpr initializer_list::size? And, of course, does the time window
to add it to the FCD is still open?

Cheers,
Rodolfo Lima


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From: Daniel Krügler on 7 Jul 2010 12:49
On 7 Jul., 22:11, Rodolfo Lima <rodo...(a)rodsoft.org> wrote:
> On Jul 3, 7:50 pm, Rodolfo Lima <rodo...(a)rodsoft.org> wrote:
>
> > In my proposal, in cases where the list's size isn't needed at compile
> > time, the partial specialization would be used, making
> > initializer_list not dependent on list's size (would be the case for
> > std::vector, for instance). Only when I *want* different
> > instantiations for different sizes the base template (dependent on
> > list's size) would be used. The way I see it is a win-win situation,
> > isn't it?
>
> Does anyone think that this might be a solution to the problem of
> constexpr initializer_list::size? And, of course, does the time window
> to add it to the FCD is still open?

It is probably best to have a full-fledged proposal.[1]
This proposal should also respond to expected questions
in regard to the two template parameters instead of one
and should emphasize which problems it solves (and which
it doesn't).

Don't take this too light-hearted: You probably have
to guess the chances of acceptance of such a proposal
because an FCD will typically change slightly and only
if really needed. A second problem is: This proposal
would probably have worse chances in the future, because
you would then break programs that rely on the fact the
std::initializer_list has only one template parameter
currently (e.g. programs that use a template template
parameter).

I don't want to discourage you, but I attempt to give
a fair estimate, because I know that providing such
a proposal is a lot of work.

As a personal opinion - and not more! - I would recommend
to make instead a proposal that requires that the size()
function of std::initializer_list is required to be
constexpr in all situations without adding another template
parameter - this solution would not introduce the
two parameters and it would solve the problem for
all cases.

HTH & Greetings from Bremen,

Daniel Kr�gler

[1] I just replied to a similar posting in regard to the
way of submitting an official proposal, so here only a
short description: Write a proposal as html or PDF and send
it to the e-mail address given on top of

http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html

because this is a library-related problem.


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