Re: [Boost-users] C++ Template Metaprogramming Book - Chapter 4

From: Eduardo Bezerra (edubez_at_[hidden])
Date: 2006-06-19 15:02:09

Yes Felipe, I am :-)

Obrigado pela ajuda

On 6/19/06, Felipe Magno de Almeida <felipe.m.almeida_at_[hidden]> wrote:
> On 6/19/06, Eduardo Bezerra <edubez_at_[hidden]> wrote:
> > Hi,
> >
> > In C++ Template Metaprogramming chapter 4, item 4.1.2. Lazy Type Selection
> > typename is_scalar<T>::type and is_scalar<T> can be used interchangeably
> > as in the example below:
>
> [snipped example]
>
> > I'm still trying to figure out the reason why.
> >
> > I understand that to invoke a metafunction you have to reach into its
> > nested ::type member and I also know that integral constant wrappers
> > have a ::value member.
>
> is_scalar<T> inherits from true_type or false_type, which work for
> both concepts: integral constant (::value) and nullary-metafunction
> (::type).
>
> >
> > Any help would be greatly appreciated
> >
> > Regards,
> > Eduardo
>
> PS: Are you from brazil?
> --
> Felipe Magno de Almeida
> Consultor - Expertise Solutions
> http://www.expertisesolutions.com.br
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