Re: [boost] boost.parameter defaults

Subject: Re: [boost] boost.parameter defaults
From: Jeffrey Lee Hellrung, Jr. (jhellrung_at_[hidden])
Date: 2010-07-11 13:19:10

On 7/11/2010 9:57 AM, Tim Blechmann wrote:
> hi all,
>
> i am currently having a hard time to figure out, how to use boost.parameter
> with default template arguments.
>
> i have a signature:
>
> typedef parameter::parameters<optional<tag::a>,
>                                optional<tag::b>
>                               >  foo_signature;
>
> template<class X,
>            class A = boost::parameter::void_,
>            class B = boost::parameter::void_>
> class foo
> {};
>
> now, how do i set a default parameter for one of the template arguments? it
> is either not documented, or i am missing the point, where it is explained
> ...
>
> thanks, tim
>

Try using boost::parameter::binding ...?

typedef typename boost::parameter::parameters<
     ...
 >::bind< A, B >::type bound_params_type;
typedef typename boost::parameter::binding< bound_params_type, [tag], 
[default] >::type ... ;

I'm only copying this from code I wrote using the Boost.Parameter 
library some time ago, so not sure if this is the recommended way...

- Jeff