om values to values. The <CODE>&lt;key&gt;</CODE>
values are restricted to simple values: integers, floating-point numbers,
strings, files, directories, and arrays of simple values.</P><P>The Map object provides the following methods.</P><UL CLASS="itemize"><LI CLASS="li-itemize">
<CODE>$(o.length)</CODE>: the number of items in the map.
</LI><LI CLASS="li-itemize"><CODE>$(o.mem &lt;key&gt;)</CODE>: returns <CODE>true</CODE> iff the <CODE>&lt;key&gt;</CODE> is defined
in the map.
</LI><LI CLASS="li-itemize"