Re: [Boost-users] [parameters] Runtime enumeration of parameter list

From: David Abrahams (dave_at_[hidden])
Date: 2005-12-11 08:12:00

Joel de Guzman <joel_at_[hidden]> writes:

> David Abrahams wrote:
>> "Neil Hunt" <boost_at_[hidden]> writes:
>> 
>> 
>>>I guess the main thrust of the question is "Does the parameters library 
>>>support runtime enumeration?"
>> 
>> 
>> Not directly, but it seems like something we (sh/c)ould support,
>> probably by making ArgumentPacks conforming Fusion sequences so you
>> could use boost/spirit/fusion/algorithm/for_each.hpp to enumerate them.
>> The problem is that I don't have expertise with Fusion-1 and AFAIK it's not
>> fully documented.  Specifically, I don't know how to make a conforming
>> Fusion sequence.  Maybe Joel can help.  Joel?
>
> Sure. I'll look into it. Should be a good example for the docs
> in the making. I'm a bit hesitant to write this for Fusion-1,
> however, as it will be replaced by Fusion-2

I know; I was just thinking that Neil is probably not going to want
to check out a branch.

>  --which, BTW, has a "map" that might be a good replacement for
> boost parameter's internals. 

Might be.  Boost.Parameter's internals have a bunch of stuff in them
that isn't simply a map.  And furthermore, that library works on
broken compilers :(

> If boost.parameter uses fusion::map,
> then you automatically have iteration support plus all the
> algorithms etc. I bet fusion::map will simplify boost.parameter
> significantly too.

Unless you make it "portable."  The main motivation for making
Boost.Parameter "portable" was that I wanted to use it in
Boost.Python.  But then again, maybe it will be possible to drop vc6/7
support from Boost.Python soon enough.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com