on Fri Aug 10 2007, Mathias Gaunard <mathias.gaunard-AT-etu.u-bordeaux1.fr> wrote:
Ion Gaztañaga wrote:
I don't know much about Boost.Parameter but my goal is maintain Boost.Intrusive independent of heavy template-metaprogramming machinery, because the library is adequate for embedded systems and I wouldn't want the executable to grow with type-info information/increased compilation time created by meta-programming (I might absolutely wrong with this sentence, so please feel free to correct).
It's not the first time I've seen this, and I still do not understand what the belief of template meta-programming causing bloat is based on.
It certainly increases compilation time, of course, since the point is to create a domain specific language for the problem domain -- using the type system -- and evaluate it at compile-time to generate the best targeted code, but it certainly doesn't make the executable needlessly grow at all. All information about types is lost once a program is compiled. (apart from debugging information, of course)
Imagine you have a function [template] f using named parameters. Then f(n = 4, s = "hello"); and f(s = "hello", n = 4); instantiate different specializations of f at the top level even though the two are functionally equivalent. Of course, everything in f that generates substantial code can be in an implementation function -- say, f_impl -- whose template parameters are identical for the two invocations, so in the end I don't think there's much to worry about. f simply gathers up and distributes references to its arguments. -- Dave Abrahams Boost Consulting http://www.boost-consulting.com The Astoria Seminar ==> http://www.astoriaseminar.com