Re: [boost] [parameter] BOOST_PARAMETER_CONSTRUCTOR bug

Subject: Re: [boost] [parameter] BOOST_PARAMETER_CONSTRUCTOR bug
From: Cromwell Enage (sponage_at_[hidden])
Date: 2013-06-07 18:15:19

Hello, James.

In order to enable argument deduction, you need to augment your parameter declaration clause with either an explicit type or a Unary Metafunction Class--essentially an MPL Lambda Expression--that returns mpl::true_ when the argument type fulfills the requirements you want to impose on it.  Try one the following macro invocations:

BOOST_PARAMETER_CONSTRUCTOR(
    myclass, (myclass_impl), tag            ,   (optional (name, (char const*)) (index, (int))
                )
                (deduced
                    (optional (ratio, (double)))
                )

)


or

BOOST_PARAMETER_CONSTRUCTOR(
    myclass, (myclass_impl), tag            ,   (optional (name, (char const*)) (index, (int))
                )
                (deduced
                    (optional (ratio, *(boost::is_floating_point<boost::mpl::_>)))
                )

)

HTH,
Cromwell D. Enage