On Thu, Sep 11, 2008 at 05:13:15PM +0200, JOAQUIN M. LOPEZ MU?OZ wrote:

________________________________________ De: boost-users-bounces@lists.boost.org [boost-users-bounces@lists.boost.org] En nombre de Zeljko Vrba [zvrba@ifi.uio.no] Enviado el: jueves, 11 de septiembre de 2008 17:05 Para: boost-users@lists.boost.org Asunto: Re: [Boost-users] Puzzled: compiler can't find a match for functioncall

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Indeed it works. Could you please explain why the compiler can deduce K in BF::map > , but not in typename id_t<K>::type?

Suppose that id_t<K1>::type == id_t<K2>::type == int (for instance). If we pass int, how can the compiler figure out whether it's K1 or K2 that has to be deduced?

True, but it could look into the ::type typedef, see that it depends on the id_t template argument, and proceed in the same way as when you give it explicitly written out type. (In fact, that's what I expected would happen, since typedef just declares a type alias, not a new type.) OK, I was unsuccessfully trying to make a "template-typedef". Is there a way in which I can shorten BF::map > to just something like id_t<K>, but that works with type-deduction?