- improved EDOAL documentation

html/edoal.html

@@ -1000,15 +1000,17 @@ specified. Depending on the use of the alignments, operators may be
 implemented in various way. In order to provide a useful and portable way to
 express operations, EDOAL promotes the use of the following conventions:
 <dd>
-<dt>XPath functions (fn:<i>name</i>)</dt>
+<dt>XPath functions (fn:<i>name</i>, op:<i>name</i> and xs:<i>type</i>)</dt>
 <dd>Operators from
-the <a href="http://www.w3.org/TR/xquery-operators/">XQuery 1.0 and
-  XPath 2.0 Functions and Operators</a> recommendation.
+the <a href="http://www.w3.org/TR/xpath-functions-3/">XQuery and
+  XPath Functions and Operators</a> (3.1) recommendation.
 This is the recommended way to identify functions because they have
   URIs and the XPath library is already quite large.
 (<tt>fn:</tt> prefix used
   for <tt>http://www.w3.org/2005/xpath-functions</tt> and <tt>op</tt>
-  prefix used as a convention and does not corresponds to a URI prefix!)</dd>
+  prefix used as a convention and does not corresponds to a URI
+  prefix! In addition, the <tt>xs:</tt> prefix for <tt>http://www.w3.org/2001/XMLSchema</tt> is used for type
+  coercion as with the "as" operation)</dd>
 <dt>SPIN function (sp:<i>name</i>)</dt>
 <dd>It would be convenient to use standard SPIN functions as
   well. However, SPIN functions are usually declared in another