lowing expression is lazily evaluated:
      </p>
<pre class="programlisting"><span class="special">-(</span><span class="identifier">arg1</span> <span class="special">+</span> <span class="number">3</span> <span class="special">+</span> <span class="number">6</span><span class="special">)</span>
</pre>
<div class="orderedlist"><ol class="orderedlist" type="1">
<li class="listitem">
            Following rule 1, <code class="computeroutput"><span class="identifier">arg1</span> <span class="special">+</span>