html">stop_if</a></span>(<span class="dt">.x =</span> x, </a>
<a class="sourceLine" id="cb27-4" title="4">        <span class="dt">.p =</span> is.numeric)</a>
<a class="sourceLine" id="cb27-5" title="5"><span class="co">#&gt; Error: Test `is.numeric` on `x` returned an error.</span></a>
<a class="sourceLine" id="cb27-6" title="6"></a>
<a class="sourceLine" id="cb27-7" title="7">y &lt;-<span class="st"> "20"</span></a>
<a class="sourceLine" id="cb27-8" title="8"><span class="co"># stop if .x is not numeric</