Re: [Boost-users] [parameter] Parameter-Enabled Class Templates: combining keyword and deduction for the same parameter

From: David Abrahams (dave_at_[hidden])
Date: 2007-07-19 15:02:43

on Thu Jul 19 2007, Joaquín Mª López Muñoz <joaquin-AT-tid.es> wrote:

> The docs explain that a parameter can be named:
>
>   typedef parameter::parameters<
>     required<tag::threading_policy>
>     ...
>   > class_signature;
>   ...
>   class_<threading_policy<single_threaded>,...>;
>
> or else be deduced:
>
>   typedef parameter::parameters<
>     required<
>       deduced<tag::threading_policy>,
>       is_base_and_derived<threading_policy_marker,_>
>     >
>     ...
>   > class_signature;
>   ...
>   class multithreaded: threading_policy_marker{...};
>   class_<multithreaded,...>;
>
> Now, is it possible to combine these two options into one, so that the
> the two syntaxes
>
>   class_<threading_policy<single_threaded>,...>;
>   class_<multithreaded,...>;
>
> are accepted? If so, how?

Just used deduced<tag::threading_policy>; deduced parameters can be
deduced from argument types or from the names attached to named
arguments.

-- 
Dave Abrahams
Boost Consulting
http://www.boost-consulting.com
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