Message du 08/05/11 12:57 De : "Vladimir Batov" A : boost@lists.boost.org Copie à : Objet : Re: [boost] [convert] no-throw and fallback feature
From: "Vicente BOTET" Hi,
I was thinking on the fallback feature a little bit more and I've the impression that we can get it for free. If we accept that we need a no-throw function such as try_convert_to that returns an optional Target we can have the fallback using the optional::get_value_or function
auto r = try_convert_to(*int*)(s); int i = r.get_value_or(fallback); ... I don't know if it is worth adding a function that does all in one
int i = convert_to_or(*int*)(s, fallback);
Vicente,
Your suggestion of deploying get_value_or() indeed provides the fallback feature quite easily. However, the original 2 args function
Target v = convert_to_or(s, fallback);
does that and more. :-) It does not require the Target type to be DefaultConstructible. Something dear to my heart. :-)
You are right, convert_to_or can be specialized for non default constructible types and could even perform better. What others think of the naming and signatures? Best, Vicente