On 03/27/09 10:43, Steven Watanabe wrote:
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. [snip] 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.
Ah! Thanks. Now, on a related matter, what's the rationale for vector0::lower_bound_::value == 32768 as shown here: https://svn.boost.org/trac/boost/browser/trunk/boost/mpl/vector/aux_/vector0... and what's the rationale for at_front=0 here: https://svn.boost.org/trac/boost/browser/trunk/boost/mpl/vector/aux_/item.hp... The only reason, AFAICT, for the at_front value is that the vectorI specializations here: https://svn.boost.org/trac/boost/browser/trunk/boost/mpl/vector/aux_/preproc... for some reason add items starting from the tail, as shown at: https://svn.boost.org/trac/boost/browser/trunk/boost/mpl/vector/aux_/preproc... However, if the items were added from the head, then at_front=1 could be used. The reason that would be desirable is that it enables the variadic template compiler to used to simplify the mpl::vector implementation, as shown here: TinyURL.com/cof5br The reason I'd like to know the vector0::lower_bound_::value rationale is I'd like to add that to the in source documentation. However, as you can see from looking at the current mpl/vector/aux_/vector0.hpp source file, I can't figure out a good reason for 32768. Thanks very much for your help, Steven. -regards, Larry