n prints all the fields of a
map <CODE>o</CODE>.</P><PRE CLASS="verbatim">   PrintMap(o) =
      o.foreach(v, x) =&gt;
         println($(v) = $(x))
   </PRE><P>The <CODE>export</CODE> form is valid in a <CODE>foreach</CODE> body. The following
function reimplements the <CODE>key</CODE> method.</P><PRE CLASS="verbatim">   FieldNames(o) =
      names =
      o.foreach(v, x) =&gt;
         names += $(v)
         export
      return $(names)
   </PRE></LI></UL><P>There is also simpler syntax when the key is a 