From: Matthias Schabel (boost_at_[hidden])
Date: 2007-02-20 15:31:10
>> There seems to be a problem with this, actually : what if I want
>> tags in different systems?
>> typedef heterogeneous_system<
>> mpl::pair<length_tag,CGS::system> > >
>> Then the mpl::at becomes a problem, I believe...
> For this case we need to make the system store
> basically all the information that we were putting
> into the dimension list. I think this solution to be
> better because overloading by dimension is
> easy and the extra work would probably have to
> be done anyway.
You're probably right - limiting heterogeneous systems
to one system per tag is a reasonable constraint and
will make the implementation issues much less sticky
for both operators and conversions...
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