Re: [Boost-users] [fusion] runtime unsigned to a template argument compile-time unsigned

Subject: Re: [Boost-users] [fusion] runtime unsigned to a template argument compile-time unsigned
From: Hicham Mouline (hicham_at_[hidden])
Date: 2010-02-22 14:59:47

-----Original Message-----
From: "Larry Evans" [cppljevans_at_[hidden]]
Date: 22/02/2010 07:23 PM
To: boost-users_at_[hidden]
Subject: Re: [Boost-users] [fusion] runtime unsigned to a template argument
 compile-time unsigned

On 02/22/10 10:02, Larry Evans wrote:
> On 02/21/10 05:27, Hicham Mouline wrote:
> [snip]
>>>
>> 3.       Can I generate an array of function pointers to the various 
>> at<>() functions and call the right one at runtime?
> 
> The 2 attached files show how this can be done.
> 
> Obviously, instead of:
> 
>         typedef
>       void(*
>     method_type
>     )(void)
>     ;
> 
> you'd have:
> 
>         typedef
>       double(*
>     method_type
>     )(void)
>     ;
> 
This could even be done for heterogeneous return types; however,
in that case, a tagged variant.  The tag for this variant would
be the field index.  In the attached code, this would be something
like the super_numerals.

------------------------

This looks like it should go, already is in some library?

I have many places where I read the index, and I would like to use the index as the template argument,

thanks very much, will do,