On Fri, Nov 4, 2011 at 10:53 PM, Cromwell Enage <sponage@yahoo.com> wrote:
From: Lorenzo Caminiti
The following example raises the same Boost.Parameter error and it uses no graph library:
// File: 01.cpp #include <boost/parameter.hpp> #include <iostream>
BOOST_PARAMETER_NAME(x) BOOST_PARAMETER_NAME(y)
BOOST_PARAMETER_FUNCTION( (void), f, tag, (required (x, *) (y, (tag::x::_)) ) ) { std::cout << x << " " << y << std::endl; }
int main ( void ) { f(1, 2); return 0; }
Reply: IME you can't use (void) as a return type. As a workaround I use (bool) and return a constant (true or false).
Thanks but that's not the issue: 1) If you remove the tag::x::_ (e.g., use int for y's type) then it compiles with (void), (bool), and any other result type. 2) If you leave the tag::x::_ as y's type then it does not compile with neither (void), (bool), or any other result type (for all result types you get the same error as above). As far as I understand, the last error about the result type might be induced by the first error which is about mpl::_2 not being bound to a Boost.Parameter argument pack-- who should do that binding? how? Please someone help :) NOTE: I can't implement Boost.Contract support for named parameter without this feature because within the contract macros I need to refer to the parameter types. This is a blocking issue for integrating Boost.Parameter in Boost.Contract!! --Lorenzo