define BOOST_PP_NODE_13(p) BOOST_PP_IIF(p##(13), 13, 14) : <p>boost 
auto_rec.hpp</p>

<p>What does mean p##(13) here:
define BOOST_PP_NODE_13(p) BOOST_PP_IIF(p##(13), 13, 14)</p>

<p>In what it translates?</p>
