[boost] boost.parameter defaults

Subject: [boost] boost.parameter defaults
From: Tim Blechmann (tim_at_[hidden])
Date: 2010-07-11 12:57:38

hi all,

i am currently having a hard time to figure out, how to use boost.parameter 
with default template arguments.

i have a signature:

typedef parameter::parameters<optional<tag::a>,
                              optional<tag::b>
                             > foo_signature;

template <class X,
          class A = boost::parameter::void_,
          class B = boost::parameter::void_>
class foo
{};

now, how do i set a default parameter for one of the template arguments? it 
is either not documented, or i am missing the point, where it is explained 
...

thanks, tim

-- 
tim_at_[hidden]
http://tim.klingt.org
Which is more musical, a truck passing by a factory or a truck passing
by a music school?
  John Cage