Re: [boost] Boost Units library preview

From: Ben Strasser (strasser.ben_at_[hidden])
Date: 2006-08-29 14:09:18

Andy Little <andy <at> servocomm.freeserve.co.uk> writes:

> "Ben Strasser" <strasser.ben <at> googlemail.com> wrote in message 
> news:loom.20060829T180704-945 <at> post.gmane.org...
> 
> > In more complex situations you run accross the 
> > problem that you can no longer
> > deduce the correct unit type. This is 
> > also the reason why PQU (= Physical
> > Quantities Units) has introduced annomymous 
> > units. However in what way does this
> > help? None that I can think of because in both situation (meaning non 
> > printable units and annomymous units) the users 
> > has to indicate how to print the units.
> 
> FWIW, if this is a statement regarding Quan, then it is incorrect

Then please correct me. Somewhere in this 
same thread you said:

> In the calculation:
>
> force * distance;
>
> The programmer might be dealing with a 
> force acting at a moment, or the energy 
> required to move an object. There is no 
> way to tell from the calculation which. 
> [...] , so the result is an 
> anonymous quantity.
>
> One could apply various rules [...], but as I 
> can't apply a rule easily to the above case, 
> I opted to apply the same rule to every case 
> of  dimensionful multiplication and division, 
> which was to return an anonymous quantity and 
> leave it to the programmer to decide which 
> quantity they were dealing with.

The way I understood this is that the library isn't 
able to deduce what symbol corresponds to the units
so the user has to make a choice. 

Did I misunderstand this or did I only get 
the terminology wrong?