[boost] Re: runtime unit-modifiablephysical-quantitiesusingpqs1-00-01

From: Dan W. (danw_at_[hidden])
Date: 2004-01-05 06:23:21

Daniel Frey wrote:

> Dan W. wrote:
> 
>> Start again.  You'll get the right thing done in a snap, now.  ;-)
>>
>> Simplest solution that could possibly work, but no simpler than the 
>> simplest solution to *use*:
>>
>> using boost::unit_system::dimensions;
>>
>> dim length;
>> dim time;
>> dim speed;
>> dim hertz;
> 
> 
> Wait! I think the above mixes up some important concepts. Look at this:
> 
> length     <-> meter
> time       <-> hour
> speed      <-> mph
> frequency  <-> hertz
> 
> I hope you see what I mean. 'hertz' is IMHO totally different than 
> length, time or speed.
> 
> Speaking in C++, I think that length, time, speed and *frequency* are 
> the (C++-)type, where meter, hour, mph and *hertz* are constants of the 
> corresponding type. This is also important if it comes to different 
> systems and conversions. SI-units like meters and other system using 
> miles, feet or whatever all represent lengths.

Damn good point! Dimensions are too abstract to matter.