Re: [boost] Interest in dimension/unit-checking library?

From: Matt Calabrese (rivorus_at_[hidden])
Date: 2005-11-21 15:28:00

On 11/21/05, Andy Little <andy_at_[hidden]> wrote:
>
> I presume that Matt
> Calabrese is also working on his submission, which takes a radically
> different
> approach from the sound of it.

Yup, it's still in the works. I'm currently in the process of switching over
to using Eric Niebler's Proto library internally for dealing with expression
templates (a sublibrary which was used in xpressive), as opposed to the
bare-bones expression templates I was developing.

As a side note, if any other unit library developers are interested (or
anyone else), I recently made a simple metafunction for yielding integral
and floating point promotions (4.5 and 4.6), as well as a binary
metafunction for yielding the type after usual arithmetic conversions (5p9),
both of which are almost essential for elegantly obtaining the return types
of common operations on arithmetic types. They're extremely useful for
determing the proper return type of common forwarded unary and binary
operations of quantities to an underlying arithmetic value type, such as for
negation (which implies a promotion) or subtraction (which implies usual
arithmetic conversions). If people haven't already developed their own
solutions and would like these (already boostified), they are very small and
quick to upload. Both just examine compiler behavior to determine the
appropriate datatypes. They work with extended types such as long long, and
promotion works correctly even with enum types as input.

--
-Matt Calabrese