Re: Quantity libraries: SIunits

From: eford_at_[hidden]
Date: 2001-09-15 16:13:56

> This looks good to me. It's exactly what I have but without using 
> the boost classes (which makes it a lot easier and cleaner). Add 
> something like
> 
> template <class NewUnitType, class OldUnitType>
> NewUnitType 
>   unit_cast<NewUnitType,OldUnitType>(OldUnitType quantity);

right, I meant for people to provide those.

> plus classes defining derived units (ratios, powers, products),
> and you've pretty much got it all. Use template specialization to 
> implement only the conversions that you want.

Well, if you want to provide for ratio and powers of units, then
you'll need a much more involved framework, one much more like
SIunits.  I was asking if what you had in mind was something that did
not provide for automatically creating derived units.  If you're want
something to automatically deal with derived units, I don't think my
unit_unconvertible isn't extensible that far.  I think it's  better
suited to something like making sure you only perform operations
involving sugar with other operations involving sugar.

> Then to define a framework for something like SIUnits, you just 
> define a dimension class very similar to the unit class below that 
> contains among other things
> a template constructor like

I don't think so.  SIunits uses a list of ratios for each possible
dimension.  I don't think you can to map such a list of ratios to a
single bounded integer.