de class="arg-name">body</code> is executed in the resulting lexical environment.</p>
</div>

<p>By &ldquo;object hierarchy&rdquo;, we understand a tree of nested JSON <code class="json">Object</code>s (without intervening <code class="json">Array</code>s).  Structured keys are symbols whose names consist of parts separated by periods and serve as paths into this tree.  In an <code class="json">Object</code> <var>D</var>, one-part name <var>S</var> (without any periods) refers to the <code class="json">Valu