On 10/19/13 12:49, Louis Dionne wrote:
pfultz2
writes: [...]
Then we have O(1) lookup using decltype:
template
struct at { typedef decltype(Vector::item_(Index())) type; }; I haven't tested this code yet, but the Boost.MPL works in a similiar way for compilers that suppor typeof. Of course generating the `item_` overloads
[...]
That's how the map is currently implemented, but I don't use the preprocessor to generate overloads.
See the top of [1] for details, it's pretty simple.
Regards,
Louis Dionne
[1]: github.com/ldionne/mpl11/blob/master/include/boost/mpl11/container/map.hpp
Hi Dionne, I tried variadic templates several years ago. The code is here: http://svn.boost.org/svn/boost/sandbox/variadic_templates/boost/mpl/ Unfortunately, as Eric and Mathias already hinted, the compile times are much slower than with the existing mpl. The existing mpl uses the preprocessor to lessen compile times, a method mentioned by Eric in his (b) item: (b) using the preprocessor and living with arbitrary limits. Christopher Schmidt used the preprocessor to implement a variadic fusion using the help of the preprocessor to lessen compile times but, IIUC, he used some method (I'll call it "chunking") so that the preprocessor didn't have arbitrary limits: http://lists.boost.org/Archives/boost/2012/03/191091.php NOTE: I tried the link in that post to Christopher's code and it no longer works :( However, I'm sure Christopher (if you can find his email address) would be able to supply an update location for the code. You might could use the chunking method to minimize the compile times. HTH. -regards, Larry