Re: [boost] [type_traits] adding is_less_comparable<T>, etc.

Subject: Re: [boost] [type_traits] adding is_less_comparable<T>, etc.
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2009-09-01 08:21:18

Frédéric Bron wrote:
>
> > I think is_greater_than can be less restrictive than it is.
>  std::greater() provides an operator that permits comparing
> unrelated types as T's.  Therefore, I wonder if this would work:
> >
> >   template <class T, class U = T>
> >   struct is_greater_comparable;
> >
> > Then, is_greater_comparable<int, float> would inherit from
> true_type.
>
> I have tried to do that but cannot understand why it does not work.
> Can you try this example and tell me why it does not give false each
> time?

Yes

[snip]
> template < typename T, typename U >
> struct is_less_comparable_impl {
>    static typename boost::remove_cv<T>::type &t ;
>    static typename boost::remove_cv<T>::type &u ;

Change that last line to:

     static typename boost::remove_cv<U>::type &u ;

_____
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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