type_traits / MPL interoperability
I just ran into a problem caused by the TR1-ization of the type traits library. I had a function defined this way: template <class T> typename is_fundamental<T>::type f(T) { return mpl::bool_< is_fundamental<T>::value >(); } that wouldn't compile. Eventually I discovered that it was because type traits now yield instances of integral_constant<T,N> (is that documented somewhere now?) integral_constant<T,N> is derived from mpl::integral_c<T,N>, but mpl::bool_<N> is not derived from integral_constant<T,N>. I can understand not wanting to introduce that sort of two-way coupling between the libraries, but it also seems like the only way to make everything work smoothly. Thoughts? -- Dave Abrahams Boost Consulting www.boost-consulting.com
"John Maddock" <john@johnmaddock.co.uk> writes:
integral_constant<bool,b> derives from mpl::bool_<b> for backwards compatibility.
For still more backward compatibility we ought to have a conversion in the other direction.
Stupid answer: broken compiler workaround. Anyway, this isn't a big deal. Maybe not even worth acting on. -- Dave Abrahams Boost Consulting www.boost-consulting.com
participants (2)
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David Abrahams -
John Maddock