Re: [boost] [convert] no-throw and fallback feature

Subject: Re: [boost] [convert] no-throw and fallback feature
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2011-05-10 13:49:08

Vicente BOTET wrote:
> De : "Stewart, Robert"
>
> > It appears that we're suggesting that opt_tie() be
> > overloaded:
> >
> > int i;
> > bool b;
> > opt_tie(i, b) = convert_to<optional<int>>(s);
> > if (!b)
> > {
> >    i = fallback;
> >    std::cerr << "using fallback\n";
> > }
> >
> > and
> >
> > i = fallback;
> > opt_tie(i) = convert_to<optional<int>>(s);
>
> No. I don't think the overload with the boolean parameter is
> really useful and it is a little bit confusing to have both.

I don't think having both would be confusing.

Without the bool overload, there's try_convert_to() or using optional overtly:

optional<int> const o(convert_to<optional<int>>(s));
if (o)
{
   // use o.get()
}
else
{
   // use a fallback value
   std::cerr << "using fallback\n";
}

The opt_tie() bool overload is a bit simpler, don't you think?

For general use with optional, I think the opt_tie() overload might be useful.

_____
Rob Stewart                           robert.stewart_at_[hidden]
Software Engineer                     using std::disclaimer;
Dev Tools & Components
Susquehanna International Group, LLP  http://www.sig.com





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