processor>#define </span><span class=identifier>BOOST_SPIRIT_DEBUG  </span><span class=comment>///$$$ DEFINE THIS BEFORE ANYTHING ELSE $$$///
    </span><span class=preprocessor>#include </span><span class=string>&quot;boost/spirit/include/classic.hpp&quot;

    </span><span class=comment>/***/

    /*** CALCULATOR GRAMMAR DEFINITIONS HERE ***/

    </span><span class=identifier>BOOST_SPIRIT_DEBUG_RULE</span><span class=special>(</span><span class=identifier>integer</span><span class=special>);
    </span><