Re: [boost] [fusion] at_c<> where index is a runtime variable

AMDG Larry Evans wrote:

Steven, there was also something on the c.l.c++.m newsgroup about this. There's even a comparison with switch_ here:

http://groups.google.com/group/comp.lang.c++.moderated/msg/771d715f3f238fee

Ok. I think that the easiest way to state the difference is that Switch is a lower level generic component, while the solution proposed there is specific to accessing tuples. Both the performance considerations mentioned in that post can be implemented on top of switch. Optimizing away the default can be handled by passing a function object like template<class R> struct never_called { template<class N> R operator()(N) { __assume(0); } }; In Christ, Steven Watanabe