 class="identifier">human_format</span> <span class="special">=</span> <span class="string">"$1-$2-$3-$4"</span><span class="special">;</span>

<span class="identifier">UnicodeString</span> <span class="identifier">human_readable_card_number</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">UnicodeString</span><span class="special">&amp;</span> <span class="identifier">s</span><span class="special">)</span>
<span class="special">{</span>
   <span class="keyword"