[boost] Re: Dimensional Analysis Interest?

From: David Richardson (dgr24_at_[hidden])
Date: 2003-10-16 07:58:34

David Abrahams wrote:

> Well, you can make "compile-time rationals", but they can't look like 
> our Boost rational class because the numerator and denominator have to 
> be part of the type.

The syntax I ended up with is a bit messy, but it works.  You can 
use it as:

typedef Rational::New<1,2>::type oneHalf;
typedef Rational::New<3,2>::type threeHalves;

//all rationals are stored in reduced terms
Rational::Add<oneHalf, threeHalves>::type two;

//get at the numerator and denominator
assert(two::n == 2);
assert(two::d == 1);

There are 'methods' for addition, subtraction, multiplication, 
division, and absolute value.

I considered arbitrary precision compile-time integers for the 
numerator and denominator, but that seemed like far too much work 
for no clear payoff.

Dave