Re: [boost] [Review] Quantitative units - compile time vs runtime

From: Steven Watanabe (steven_at_[hidden])
Date: 2007-03-28 11:58:09

AMDG

Michael Fawcett <michael.fawcett <at> gmail.com> writes:

> <snip>
> 
> > No more switch statement smell.
> 
> I agree on the smell...Thankfully it's very contained when using the
> compile-time version.  It seems like with a run-time component that
> was interoperable with the compile-time one, you could have zero
> run-time overhead during computations as well as get rid of all switch
> statements at the boundaries (reading/writing from database or GUI).
> Something like:
> 
> quantity<SI::length> on_dialog_ok()
> {
>    quantity<abstract> dist;
>    dist.set_unit(combo.selected_item().data());
>    dist.set_value(entry.value().as_double());
>    return quantity<SI::length>(dist);
> }
> 

Here is how I would do it:

quantity<SI::length> on_dialog_ok()
{
   double conversion = combo.selected_item().data();
   double value = entry.value().as_double();
   return quantity<SI::length>::from_value(conversion * value);
}

Absolutely minimum overhead.

In Christ,
Steven Watanabe