AMDG Joel de Guzman wrote:

Steven Watanabe wrote:

...

My concern is 1) fall-through can't easily be added to the interface.

I have an idea I'd like to post in another update to the case concept.

Great.

The point is that it is just another case. Whatever the sequenced_case is, it's just a model of the case concept. Sure it still has to be documented, but not as a separate concept, but as a model of it.

Also, to me, it's most trivial to just make it an ET tree:

template< class CaseL, class CaseR > struct binary_case { CaseL l; CaseR r;

binary_case(CaseL const& l, CaseR const& r) : l(l), r(r) {}

typedef mpl::joint_view< typename CaseL::labels, typename CaseR::labels > labels;

template< typename Result, class I > Result apply(I); };

Key points:

* apply is part of the concept. In this case, it dispatches to l or r depending on I

* hmmm.... maybe labels should be an mpl set.

No, thank you. mpl set is buggy and slow. Also, one thing that needs to be nailed down is: What Is I? Tobias was using it as the index into the list of labels: mpl::int_<0>, mpl::int_<1>, mpl::int_<2>, ... In my original interface and as you seem to be using it I is one of: mpl::at_c<labels, 0>::type, mpl::at_c<labels, 1>::type, mpl::at_c<labels, 2>::type In Christ, Steven Watanabe