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

10 May 2011

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Message du 10/05/11 19:50
De : "Stewart, Robert" 
A : "'boost@lists.boost.org'" 
Copie à : 
Objet : Re: [boost] [convert] no-throw and fallback feature
Vicente BOTET wrote:
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De : "Stewart, Robert"
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It appears that we're suggesting that opt_tie() be
overloaded:
int i;
bool b;
opt_tie(i, b) = convert_to>(s);
if (!b)
{
i = fallback;
std::cerr << "using fallback\n";
}
and
i = fallback;
opt_tie(i) = convert_to>(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 const o(convert_to>(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.
Sorry Robert. You lost me. 
Are you using the word overload instead of conversion?

Form which overloads of opt_tie are you talking of?
opt_tie(T)
and
opt_tie(T,bool)?

Vicente