r>expression</span><span class=special>;
    </span><span class=identifier>subrule</span><span class=special>&lt;</span><span class=number>1</span><span class=special>&gt;  </span><span class=identifier>term</span><span class=special>;
    </span><span class=identifier>subrule</span><span class=special>&lt;</span><span class=number>2</span><span class=special>&gt;  </span><span class=identifier>factor</span><span class=special>;
    </span><span class=identifier>subrule</span><span class=special>&lt;</span>