ve considerations can usually be ignored if your lists are not
   longer than about 10000 elements.<br>
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<pre><span id="VALlength"><span class="keyword">val</span> length</span> : <code class="type">'a list -&gt; int</code></pre><div class="info">
Return the length (number of elements) of the given list.<br>
</div>
<pre><span id="VALhd"><span class="keyword">val</span> hd</span> : <code class="type">'a list -&gt; 'a</code></pre><div class="info">
Return the first element of the given li