SAXONICA |
EXSLT is an initiative to define a standardized set of extension functions and extension elements that can be used across different XSLT processors.
Saxon supports the EXSLT modules Common, Math, Sets, DatesAndTimes, and Random. These functions are available both in XSLT and in XQuery. The full list of EXSLT extension functions implemented is:
common (namespace http://exslt.org/common): node-set(), object-type()
math (namespace http://exslt.org/math): abs(), acos(), asin(), atan(), atan2(), constant(), cos(), exp(), highest(), log(), lowest(), max(), min(), power() [see below], random(), sin(), sqrt(), tan(). The random() function is also implemented, but it doesn't work well: since it is not a pure function, Saxon sometimes optimizes it so that successive calls all return the same value. The random:random-sequence() function is preferable.
sets (namespace http://exslt.org/sets): difference(), intersection(), leading(), trailing(), has-same-node()
dates-and-times (namespace http://exslt.org/dates-and-times): date-time(), date(), time(), year(), leap-year(), month-in-year(), month-name(), month-abbreviation(), week-in-year(), week-in-month(), day-in-year(), day-in-month(), day-of-week-in-month(), day-in-week(), day-name(), day-abbreviation(), hour-in-day(), minute-in-hour(), second-in-minute().
random (namespace http://exslt.org/random): random-sequence()
These have considerable overlap with extension function and elements that have previously been provided in the Saxon namespace. In some cases the Saxon versions of the functions remain available, for the time being, but the EXSLT versions are preferred.
There are some known restrictions:
In the set:leading()
and set:trailing()
functions,
Saxon does not implement the rule
"If the first node in the second node set is not contained in the first node set,
then an empty node set is returned." This rule prevents a pipelined implementation. Saxon returns
all nodes that precede/follow the first/last node of the second node-set in document order, whether
or not the two node-sets intersect.
EXSLT extensions that overlap XSLT 2.0 functionality have sometimes been retained in cases where they have no
impact on the Saxon core code, but in cases (such as func:function
) where the semantics are
inconveniently different from XSLT 2.0, they have been withdrawn.
The function math:power()
has been extended from the EXSLT definition to handle numeric data
types other than xs:double. The result will now be an xs:integer if the first argument is an xs:integer and
the second argument is a non-negative xs:integer. Otherwise, the result will be an xs:decimal if the first argument is
an xs:decimal or xs:integer, and the second argument is a whole number (a number of any data type that is equal
to some integer). In other cases the arguments are converted to xs:double and the result is an xs:double.