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

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
>> 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...
>>
>
> 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...

Matthias