XSLT 2.0 and XPath 2.0 Programmer's Reference, 4th Edition (800 page)

), which determines whether upper-case letters precede lower-case ones or vice versa, and
alphanumeric
(values
yes
and
no
), which if set causes any sequence of digits to be interpreted as a number, so for example
iso-10646
will sort after
iso-646
.

Generally, if you are matching words in natural language text, you should ignore differences such as case and accents (a low-strength collation), while for sorting, a high-strength collation is appropriate: This will ensure that words that differ only in their accents are sorted in the correct way, even though they might compare as equal in a search.

For other parameters that you can include in a Saxon collation URI, see the product documentation. If you want the ultimate in control, the collation URI can identify a user-written implementation of the
java.lang.Comparator
interface.

Because collation URIs are unlikely to be portable across implementations, it's a good idea to define them as stylesheet parameters. For example, you can define a stylesheet parameter:

and then use this in a sort, by specifying:

You could also define the collation using a conditional expression, using the
system-property()
function to determine which vendor's XSLT processor is currently in use.

The
[xsl]:default-collation
attribute, which applies to everything in its scope except

elements, can specify a list of collation URIs, and a processor will use the first one that it recognizes. You can specify
http://www.w3.org/2005/xpath-functions/collation/codepoint
as the last item in the list to provide a fallback that every processor is obliged to recognize.

Extensions

The XSLT specification provides a number of mechanisms allowing extensions to be implemented in a vendor namespace, and Saxon has exploited these to the full. As well as providing extensibility mechanisms allowing you to extend the capabilities of the product, Saxon includes quite a few built-in extensions. These fall into a number of categories, described in the following sections.

Serialization Extensions

Saxon provides a number of extra serialization properties, with names in the Saxon namespace, that you can use on the

declaration and the

instruction. The two most common options are shown below.