Re: [Boost-users] [parameter] Return type dependent on parameter type?

4 Oct 2007


      On Tue, 2 Oct 2007, Daniel Wallin wrote:

[...]
...
Right. This is a doc error. You need extract the type from the argument
pack Args:
BOOST_PARAMETER_FUNCTION(
     (typename boost::parameter::value_type::type) ,
     the_function ,
     kw ,
     (required (arg1 , *))
)
{
     return arg1;
}
Unfortunately the library has a bug that prevents this from working.
This has been fixed, but not in time for 1.34. IIRC you need to apply
this patch:
http://svn.boost.org/trac/boost/attachment/ticket/1044/parameter.diff
for this to work correctly.
Great! And now, is there a simpler way to do the same thing for other 
parameters other than doing this:

BOOST_PARAMETER_FUNCTION(
     (some_return_type)
     the_function ,
     kw ,
     (required
      (arg1 , *)
      (arg2 , *(boost::is_same< boost::mpl::_ , kw::arg1::_ >))
     )      //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
)

?

-- 
Francois Duranleau

Re: [Boost-users] [parameter] Return type dependent on parameter type?

François Duranleau