Re: [boost] [parameter] parameters<> and result_of

From: David Abrahams (dave_at_[hidden])
Date: 2006-09-22 02:19:17

"Eric Niebler" <eric_at_[hidden]> writes:

> Objects of the parameters<> type are callable entities, but they do not 
> play well with result_of:
>
>
> BOOST_PARAMETER_KEYWORD(tag, foo)
>
> typedef
>    parameter::parameters< parameter::optional< tag::foo > >
> args_type;
>
> // Doesn't compile:
> typedef result_of< args_type( int const & ) >::type pack_type;
>
> args_type args;
> pack_type pack( args( 1 ) );
>
>
> Is there any way to tell what the return type of args( 1 ) is?  I
> need to be able to return an argument pack from a generic function.

I'll have to get back to you on that one.  I don't think there's a
nice way, yet.

> Another feature request: it would be nice if parameters<> were a valid 
> MPL sequence that I could manipulate with MPL algorithms.

It already is an MPL sequence.

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