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

From: J.F.K. (beholder_at_[hidden])
Date: 2004-01-06 00:53:04

----- Original Message ----- 
From: "Dan W." <danw_at_[hidden]>
Newsgroups: gmane.comp.lib.boost.devel
Sent: Tuesday, 06 January, 2004 05:09
Subject: Re: runtime 
unit-modifiablephysical-quantitiesusingpqs1-00-01
> 
> Ahhh! Yup, this is a conondrum; because I don't want to mix apples and 
> bananas, and if I do I can cast them to fruits; but how does one prevent 
> zero-power-units types from inter-converting? How about treating them 
> specially? For all non-zero power dimension types, conversions could be 
> template-instantiated as required; but zero power ones are typed as per 
> the name the user gives them, and if two names don't match you need a 
> cast or explicit conversion. Could this work? This could prevent taking 
> the arc-cosine of Federal tax by accident.
> 

stop here, please!
scalar is scalar, one could have an ability to write:
f = l1/l2 + v1/v2;
where l1 and l2 are lengths, v1 and v2 are velocities, and f 
is a scalar of cause.

The idea was already arised in this thread:
if "Federal tax" is imortant entity in your program - you 
could declare special dimention for it, and IMO it is a 
convinient way to
> prevent taking 
> the arc-cosine of Federal tax by accident.

preferred usage of units library for me:
* declare dimensions that'll be used in the program (Federal 
tax, e.t.c.)
* write my program :)

Regards,
Oleg.