private void parseDefaultCollation() throws XPathException {
        // <"default" "collation"> StringLiteral
        if (foundDefaultCollation) {
            grumble("default collation appears more than once", "XQST0038");
        }
        foundDefaultCollation = true;
        nextToken();
        expect(Token.STRING_LITERAL);
        String uri = URILiteral(t.currentTokenValue);
        ((QueryModule)env).setDefaultCollationName(uri);
        nextToken();
    }