Re: [boost] [any] boost::get style accessors

Subject: Re: [boost] [any] boost::get style accessors
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2010-04-28 14:00:25

Stefan wrote:
> Stefan wrote:
> > Christoph Heindl wrote:
> >>
> >> I couldn't find any boost::get<T> style accessors for
> >> boost::any, so I

[snip]

> > Also, for making them usable interchangeably via boost::get,
> > you need them to throw the same exception. Therefore, in
> > case you are
> > using boost::any, you probably want to rethrow bad_any_cast
> > to bad_get.
> >
> > namespace boost {
> >   template<class T>
> >   typename boost::call_traits<T>::reference get(any &a) {
> >         try {
> >             return boost::any_cast<typename
> > boost::call_traits<T>::reference>(a);
> >         } catch (boost::bad_any_cast const &) {
> throw(boost::bad_get()); }
> >   }
> >
> >   template<class T>
> >   typename boost::call_traits<T>::const_reference get(const
> any &a) {
> >         try {
> >             return boost::any_cast<typename
> > boost::call_traits<T>::const_reference>(a);
> >         } catch (boost::bad_any_cast const &) {
> throw(boost::bad_get()); }
> >   }

At that point, I think they should be on par with any_cast rather than built on any_cast so that exceptions needn't be translated.  Exception handling overhead is too costly to do it twice when it isn't necessary.

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

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