efine this to print some debugging diagnostics for parser p. This macro</p>
<ul>
  <li>Registers the parser name for debugging</li>
  <li>Enables/disables the tracing for parser depending on <tt>BOOST_SPIRIT_DEBUG_TRACENODE</tt></li>
</ul>
<p> <b>Pre-parse</b>: Before entering the rule, the rule name followed by a peek
  into the data at the current iterator position is printed.</p>
<p> <b>Post-parse</b>: After parsing the rule, the rule name followed by a peek
  into the data at the current iterator positi