Re: [Boost-users] Default argument values with boost::function

Artyom wrote:

Is there any way to set default argument values with Boost::Function? On VS2008 SP1 I tried:

boost::function< void( unsigned i = 1 ) > increment;

But this didn't work.

I don't think this is possible with boost::function. That reminds me Boost.Overload, which was discussed some time ago on the developers mailing list. There's something in the sandbox: https://svn.boost.org/trac/boost/browser/sandbox/overload/trunk/libs/ove rload but I'm not aware of its status. A quick and dirty alternative may be something like: namespace bft = boost::function_types; namespace bmpl = boost::mpl; template< typename FuncT, typename bmpl::at, bmpl::int_<0>

::type DefaultArg

struct UnaryFuncWithDefault { typedef typename bft::result_type<FuncT>::type ResultType; typedef typename bmpl::at, bmpl::int_<0> >::type ArgType; UnaryFuncWithDefault(const boost::function<FuncT>& Func) : m_Func(Func){} ResultType operator()(){return m_Func(DefaultArg);} ResultType operator()(ArgType Arg){return m_Func(Arg);} boost::function<FuncT> m_Func; };