span></a>
<a class="sourceLine" id="cb27-9" title="9"><span class="kw"><a href="reference/messagehandler.html">stop_if_not</a></span>(<span class="dt">.x =</span> y, </a>
<a class="sourceLine" id="cb27-10" title="10">            <span class="dt">.p =</span> is.numeric, </a>
<a class="sourceLine" id="cb27-11" title="11">            <span class="dt">msg =</span> <span class="st">"y should be numeric"</span>)</a>
<a class="sourceLine" id="cb27-12" title="12"><span class="co">#&gt; Error: y should be numeric</s