type promotion/deduction again and AGAIN :-) [ Was: Re: [boost] Re: Dimensional Analysis Feature Summary ]

From: Joel de Guzman (joel_at_[hidden])
Date: 2003-10-16 02:53:41

David Abrahams <dave_at_[hidden]> wrote:
> David Richardson wrote:
> 
> 
>> * Does not do type promotion when underlying numeric types are
>> different.  Does anyone know of existing code to do this other then what
>> is in Generative Programming/GMCL?
> 
> I suggest searching for recent postings by Joel de Guzman.  He seems to
> have worked out the ultimate scheme (within the current language
> constraints, anyway).

Although many don't realize it, this issue of type promotion comes up frequently. 
It seems that there is sufficient interest to have a type promotion/deduction utility in 
boost. The code is already in the sand-box (boost/utility/type_deduction.hpp and 
a corresponding test driver, libs/utility/type_deduction_tests.cpp ). It requires 
the currentlly being reviewed enable_if utility.

It seems worthwhile to actually go for a library proposal. Do you guys think that
the utility is a good candidate for a fast-track review? It's a simple, single header
file. What are the procedures for a fast-track review? I'd like to hear your comments.
If it's a worthwhile addition to the boost/utilities, I'll go forward with documentation
and a review request.

Regards,
-- 
Joel de Guzman
http://www.boost-consulting.com
http://spirit.sf.net