</span><span class="op">)</span></span></span>
<span class="r-in"><span>  <span class="va">expr</span> <span class="op">=</span> <span class="va">x</span><span class="op">*</span><span class="va">y</span> <span class="op">+</span> <span class="va">x</span> <span class="op">-</span> <span class="fl">3</span> <span class="op">+</span> <span class="fl">2</span><span class="op">*</span><span class="va">x</span><span class="op">**</span><span class="fl">2</span> <span class="op">-</span> <span class="va">z</span