On Mon, 06 Apr 2009 08:11:06 -0500, Larry Evans <cppljevans@suddenlink.net> wrote:
Thank you Aleksey; however, I'm not sure I made myself clear. I'm not wondering why vector has a push_back, I'm wondering why the implementation here:
https://svn.boost.org/trac/boost/browser/trunk/boost/mpl/vector/aux_/preproc...
adds from the back instead of the front. IOW, instead of:
26 template< 27 typename T0, typename T1 28 > 29 struct vector2 30 : v_item< 31 T1 32 , vector1<T0> 33 > 34 { 35 typedef vector2 type; 36 };
why not:
26 template< 27 typename T0, typename T1 28 > 29 struct vector2 30 : v_item< 31 T0 32 , vector1<T1> 33 > 34 { 35 typedef vector2 type; 36 };
The former has potential for better compilation times due to memoization gains on reusing a likely existing vector(n-1) instantiation in vector(n), e.g. vector2<T0,T1> -> vector2<T0,T1>, vector1<T0> vector3<T0,T1,T2> -> vector3<T0,T1,T2>, vector2<T0,T1>*, vector1<T0>* vs. vector2<T0,T1> -> vector2<T0,T1>, vector1<T1> vector3<T0,T1,T2> -> vector3<T0,T1,T2>, vector2<T1,T2>, vector1<T2> (*) reused instantiation Personally, I also find the first formulation more intuitive. HTH, -- Aleksey Gurtovoy MetaCommunications Engineering