AMDG Larry Evans wrote:
After viewing the code some more, I'm wondering if the memoization is not also possible with vectors with identical tails. That's because, from:
https://svn.boost.org/trac/boost/browser/trunk/boost/mpl/vector/aux_/preproc...
containing:
template< 39 typename T0, typename T1, typename T2 40 > 41 struct vector3 42 : v_item< 43 T2 44 , vector2< T0,T1 > 45 > 46 { 47 typedef vector3 type; 48 };
it appears that vector would have a memoization advantage for idential heads. For instance:
vector<T0,T1,T2_1> vs vector<T0,T1,T2_2>
from the above vector3 code:
v_item<T2_1,vector2<T0,T1> > vs v_item<T2_2,vector2<T0,T1> >
So, maybe list has an advantage for identical tails but vector has an advantage for identical heads?
No. Take a look at how the iterators for vector work. template< typename Vector , BOOST_MPL_AUX_NTTP_DECL(long, n_) > struct v_iter; Iterators into different vectors are always distinct. In Christ, Steven Watanabe