Re: [Boost-users] [MPL/Fusion?]Call a 0-args template function on members of a sequence

Edd Dawson writes:

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I'm looking for a way to call f<T>() for all types T in my_vec. I initially hoped that either an mpl algorithm or fusion::for_each might be able to accomplish this for me, but after reading through their docs this doesn't appear to be the case. struct call_f { template <class Wrapper> void operator()(Wrapper) Sorry, it's missing a "const" right here--^^^^ { f<typename Wrapper::type>(); } };

mpl::for_each >(call_f());

I didn't find this in the docs. Is it meant to be there?

The specific answer to your specific problem? No. Oh yeah, for_each wasn't documented in 1.33.1... and apparently it isn't documented in the CVS head either (still? Aleksey?)

Unfortunately, that didn't quite work for me, anyway. A requirement of for_each (according to my MSVC 8 diagnostics) is that each type in the sequence must be default constructible.

In the case above, only mpl::identity<T> needs to be default-constructible for each type in the list... or that was my intention Ach! My mistake... template <class T> struct make_identity { typedef mpl::identity<T> type; }; mpl::for_each >(call_f()); should work. -- Dave Abrahams Boost Consulting www.boost-consulting.com