span class=identifier>BOOST_SPIRIT_DEBUG_RULE</span><span class=special>(</span><span class=identifier>group</span><span class=special>);
    </span><span class=identifier>BOOST_SPIRIT_DEBUG_RULE</span><span class=special>(</span><span class=identifier>factor</span><span class=special>);
    </span><span class=identifier>BOOST_SPIRIT_DEBUG_RULE</span><span class=special>(</span><span class=identifier>term</span><span class=special>);
    </span><span class=identifier>BOOST_SPIRIT_DEBUG_RULE</span><span clas