Re: [boost] [units] Crazy idea/question

From: Matthias Schabel (boost_at_[hidden])
Date: 2007-02-19 17:02:34

> template<class DimensionMap, class Tag>
> struct unit_info<heterogeneous_system<DimensionMap>, Tag> :
>     unit_info<typename mpl::at<DimensionMap, Tag>::type, Tag> {
> };
>
> namespace MGS {
>
> typedef heterogeneous_system<
>     mpl::map<
>         mpl::pair<length_tag, SI::system>,
>         mpl::pair<time_tag, SI::system>,
>         mpl::pair<mass_tag, CGS::system>

There seems to be a problem with this, actually : what if I want  
replicate
tags in different systems?

typedef heterogeneous_system<
        mpl::map<
                mpl::pair<length_tag,SI::system>,
                mpl::pair<length_tag,CGS::system> > >

Then the mpl::at becomes a problem, I believe...

Matthias