}
// Use the numberer decided at compile time if possible; otherwise try to get it from
// a table of numberers indexed by language; if not there, load the relevant class and
// add it to the table.
Numberer numb = numberer;
if (numb == null) {
String language = lang.evaluateAsString(context).toString();
if (!StringValue.isValidLanguageCode(language)) {
throw new XPathException("The lang attribute of xsl:number must be a valid language code", "XTDE0030");
}