hmmm...
Why did you write
template<T> void addMeta(const std::string&, const Value<T>& v);
?
Wouldn't this be simpler:
template<T> void addMeta(const std::string&, const T & v);
?
Sukender
PVLE - Lightweight cross-platform game engine - http://pvle.sourceforge.net/
----- "Peter Amstutz" <peter.amst...@tseboston.com> a écrit :
> You could use an implicit constructor, e.g.
>
> template<typename T>
> class Value {
> Value(T);
> Value(const Value<T>&);
> };
>
> class Value<int>;
>
> template<T>
> void addMeta(const std::string&, const Value<T>& v) {
> Value<T>* localcopy = new Value<T>(v);
> }
>
> so the function call:
>
> addMeta("myMeta", 5);
>
> is implicitly converted to:
>
> addMeta(std::string("myMeta"), Value<int>(5));
>
>
> Two considerations:
> - There is some copying involved, which might be undesirable for
> large
> arrays. C++ 2011 move constructors are intended to solve this
> problem
> in general, but it's unlikely that OSG compatibility requirements
> will
> allow the use of C++ 2011 features for a while.
>
> - The way it is described here, any customization for Value<T> must
> occur through template specialization, rather than subclassing. To
> support subclassing, use a clone() method instead of new Value<T>(v).
>
> On a related note, my preference would be for the Value<T> class to
> be
> immutable so that you are required to set metadata values through the
> API rather than poking Value<T> objects directly. This is necessary
> if
> you want to support alternate backing stores which don't use Value<T>
> objects in the backend at all.
>
> - Peter
>
> On 4/15/2011 11:10 AM, Sukender wrote:
> > Hi Peter,
> >
> > Thanks... but what for the addMeta<T>()?
> > I mean it's okay having a addMeta(string, ValueBase *), but this
> will force you to write
> > o->addMeta( "myMeta", new Value<int>(5) );
> > instead of simply
> > o->addMeta( "myMeta", 5 );
> > which could be nice. Any idea?
> >
> > Sukender
> > PVLE - Lightweight cross-platform game engine -
> http://pvle.sourceforge.net/
> --
> Peter Amstutz
> Senior Software Engineer
> Technology Solutions Experts
> Natick, MA
> 02131
>
> _______________________________________________
> osg-users mailing list
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