k hash tables</h6><br>
<br>
A weak hash table is a hashed set of values.  Each value may
    magically disappear from the set when it is not used by the
    rest of the program any more.  This is normally used to share
    data structures without inducing memory leaks.
    Weak hash tables are defined on values from a <a href="Hashtbl.HashedType.html"><code class="code"><span class="constructor">Hashtbl</span>.<span class="constructor">HashedType</span></code></a>
    module; the <code class="code">equal</c