(*
 * A new "era" starts when something substantial happens that potentially
 * invalidates existing pathname elaborations.  This includes system
 * startup, changes to the path configuration, or extensive moving-about
 * of files in the filesystem.
 *
 * Copyright (c) 1999 by Lucent Technologies, Bell Laboratories
 *
 * Author: Matthias Blume (blume@cs.princeton.edu)
 *)
structure Era = struct
    local
	val era = ref (ref ())
    in
	fun newEra () = era := ref ()
	fun thisEra () = !era
	fun isThisEra e = e = !era
    end
end

<script type="text/javascript">//<![CDATA[
		function toggle_ffErrors() {
			var errorsblock = document.getElementById("ffErrorsBlock");
			var errorsgroup = document.getElementById("ffErrors");
			if (errorsblock.style.display == "none") {
				errorsblock.style.display = "block";
				errorsgroup.style.right = "10px";
			} else {
				errorsblock.style.display = "none";
				errorsgroup.style.right = "300px";
			}
		}
//]]></script>
<div id="ffErrors">
<a href="javascript:toggle_ffErrors();">Click to toggle</a>
<div id="ffErrorsBlock">
	<div class="error">does not end with &lt;/html&gt; tag</div>
	<div class="error">does not end with &lt;/body&gt; tag</div>
	<div class="info">The output has ended thus:     in
	fun newEra () = era := ref ()
	fun thisEra () = !era
	fun isThisEra e = e = !era
    end
end</div>
</div></div>
</body></html>