Re: [boost] [optional] rebinding references

From: Anthony Williams (anthony_w.geo_at_[hidden])
Date: 2005-10-19 06:28:52

"Fernando Cacciola" <fernando_cacciola_at_[hidden]> writes:

> // (2) Anthony's proposal:
> o.reset(rb); // still some room for doubts?

How about

o.replace_with(rb);

does that suggest rebinding? I was imagining that reset (or replace_with)
would always rebind/replace the contained element, rather than assign to
it. Then it would also work with my non-assignable types.

> // (3) Sam's proposal:
> o = make_optional(rb); // Clearly rebinds, doesn't it?

I could run with this.

As for Mat's concerns about using optionals in place of normal values:

* if the conversion constructor is not explicit, then that allows constructing
an optional<T> from a T

* we could provide a means of capturing a value into an optional:

std::pair<Foo, Bar>  do_stuff();
boost::optional<Foo>  foo;
boost::optional<Bar>  bar;

tie(rebinder(foo),rebinder(bar))=do_stuff();

Anthony
-- 
Anthony Williams
Software Developer
Just Software Solutions Ltd
http://www.justsoftwaresolutions.co.uk