on Thu Jan 22 2009, Frank Mori Hess <frank.hess-AT-nist.gov> wrote:
Does Boost.Parameter support function types as named template type parameters? I'm trying to write a metafunction which lets you use Boost.Parameter to specify the template types for a boost::signals2::signal using named type parameters, as was suggested during the review. But it doesn't seem to work for the "Signature" function type. I get errors like:
/home/fhess/svn/boost/boost/parameter/aux_/arg_list.hpp:264: error: function returning a function /home/fhess/svn/boost/boost/parameter/aux_/arg_list.hpp:270: error: function returning a function /home/fhess/svn/boost/boost/parameter/aux_/arg_list.hpp:352: error: function returning a function /home/fhess/svn/boost/boost/parameter/aux_/arg_list.hpp:359: error: function returning a function /home/fhess/svn/boost/boost/parameter/aux_/arg_list.hpp:365: error: function returning a function
It wouldn't surprise me if we had overlooked that possibility.
I can get it to work if I don't use Boost.Parameter for the "Signature" type, but only use it for the other 6 types.
Can you post a minimal example that reproduces this bug? I'm sure there's a quick fix.
Also, I noticed BOOST_PARAMETER_MAX_ARITY defaults to 5, but signals2::signal has 7 parameters. I can't reliably redefine BOOST_PARAMETER_MAX_ARITY in my library header, since it must be defined before boost/parameter/config.hpp gets included. You can't redefine the arity and then re-include the parameter library headers like you can with Boost.Function.
Oh, that's cool. Please open a ticket with a feature request for that and assign it to Daniel Wallin. -- Dave Abrahams BoostPro Computing http://www.boostpro.com