span class="identifier">x</span></code>
                is equal to the value of <code class="computeroutput"><span class="identifier">pred</span><span class="special">(</span><span class="identifier">y</span><span class="special">)</span> <span class="special">?</span> <span class="identifier">new_value</span> <span class="special">:</span>
                <span class="identifier">y</span></code> where <code class="computeroutput"><span class="identifier">y</span></code>
                is the correspondin