an class="constructor">Invalid_argument</span></code>.
   Comparison between cyclic structures may not terminate.<br>
</div>

<pre><span id="VALcompare"><span class="keyword">val</span> compare</span> : <code class="type">'a -&gt; 'a -&gt; int</code></pre><div class="info ">
<code class="code">compare x y</code> returns <code class="code">0</code> if <code class="code">x</code> is equal to <code class="code">y</code>,
   a negative integer if <code class="code">x</code> is less than <code class="code">y</co