div class="highlight"><pre><span></span><span class="k">function</span> <span class="nf">build_string</span><span class="p">(</span><span class="nv">$str</span> <span class="o">=</span> <span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="p">{</span>
        <span class="k">if</span> <span class="p">(</span><span class="nv">$str</span> <span class="o">==</span> <span class="s2">&quot;&quot;</span><span class="p">)</span> <span class="c1">// uh-oh!  What if FALSE or the integer 0 is pass