RE: [boost] new compile-time dimensional analysis and unit library

From: Paul A. Bristow (boost_at_[hidden])
Date: 2003-12-13 03:52:11

| -----Original Message-----
| From: boost-bounces_at_[hidden]
| [mailto:boost-bounces_at_[hidden]]On Behalf Of Matthias Schabel
| Sent: Friday, December 05, 2003 6:47 PM
| To: Boost mailing list
| Subject: Re: [boost] new compile-time dimensional analysis and unit
| library
|
|
| > I've finally made time  - a milli-fortnight or so ;-) to try this out.
|
| What  is that in picoeons?

Seriously for a moment, one of group who don't use SI (and reluctantly I must
admit they can't) are astronomers.  A demo using light years (or parsecs?) would
also be useful to convince people of the generality of your proposal.

| > 3 I believe it is more helpful to understand the demo if the units are
| > specified
| > thus
| >
| > using mcs::units::si::_newton;
| > using mcs::units::si::_meter;
| > using mcs::units::si::_meters; // An alias.
|
| I don't have strong feelings about this either way; if it is generally
| accepted Boost
| practice to individually alias namespace members, I'm happy to do it
| that way.

I don't think that there is a general Boost practice, but my personal view is
that it documents the things that are going to be demonstrated in this example,
but doesn't clutter the code as fully specified names like
mcs::units::si::_newton would do.

(And I don't think it would be presumptive to use the boost namespace in place
of mcs, but you would need to change the licence to the boost one from GPL).

| > 5 There are a handful of warnings that an assignment operator could not
| > be
| > generated.  The MS advice on this is:
|
| If you can give me a more detailed idea of which classes are causing
| these problems,
| I can add the appropriate operator(s).

To follow.

| > 6  I note you are using your 'own' rational.  Is there a reason you
| > are not
| > using the Boost one?
| Maybe there  would be some value in a compile-time rational class for Boost?

Very probably.

| > Some documentation would be very helpful.
|
| (it's not my day job)^(writing documentation sucks) = (very slow to
| happen)
|
| Seriously, if you (and any other potential users out there) can give me
| a clearer idea which portions of
| the library you are most interested in having documented, it's much
| more likely to become a reality.
|
| I've also posted a new version of the library in the usual place :
|
| http://groups.yahoo.com/group/boost/files/YANL.zip
|
| which cleans up some of the inner details and demonstrates creating
| hybrid unit systems from other unit systems.

I look forward to looking at this soon.

Paul

Paul A Bristow, Prizet Farmhouse, Kendal, Cumbria, LA8 8AB  UK
[phone]   Mobile [phone]
mailto:pbristow_at_[hidden]