val</span> lval_prefix : <span>string <span class="arrow">&#45;&gt;</span></span> <span><a href="#type-lval">lval</a> <span class="arrow">&#45;&gt;</span></span> <a href="#type-lval">lval</a></span></code></div><div class="spec-doc"><p><code>lval_prefix p l</code> should return the <em>l-value</em> obtained by adding prefix <code>&quot;p.&quot;</code> to the base name of <em>l-value</em> <code>l</code>. For example, if <code>l</code> is a simple variable named <code>&quot;v&quot;</code>, <code>lval_prefix &