class="code"><span class="constructor">Set_float</span></code>,
    <code class="code"><span class="constructor">Tuple</span></code>, <code class="code"><span class="constructor">Symbol</span></code>, and <code class="code"><span class="constructor">Rest</span></code>.
    <code class="code"><span class="constructor">Unit</span></code>, <code class="code"><span class="constructor">Set</span></code> and <code class="code"><span class="constructor">Clear</span></code> keywords take no argument. A <code class=