ace using <tt class="docutils literal">BOOST_PARAMETER_FUNCTION</tt>, we need
only enclose the deduced parameters in a <tt class="docutils literal">(deduced …)</tt> clause, as
follows:</p>
<pre class="literal-block">
namespace mpl = boost::mpl;

BOOST_PARAMETER_FUNCTION(
    (void), def, tag,

    (required (name,(char const*)) (func,*) )   // nondeduced

    <strong>(deduced</strong>
      (optional
        (docstring, (char const*), &quot;&quot;)

        (keywords
           , *(is_keyword_expression&l