XSLT 2.0 and XPath 2.0 Programmer's Reference, 4th Edition (539 page)
Read XSLT 2.0 and XPath 2.0 Programmer's Reference, 4th Edition Online
Authors: Michael Kay
The most common situation where
current()
is useful is when you want to follow a cross-reference from the context node to some other node. For example, the expression
//department[deptNr=current()/@dept]
finds a
dept
attribute of the context item (which might be an
Example
The following example shows the use of
current()
in a predicate.
Example: current()
This example lists the books in a catalog; in the description of each book, it also lists other books in the same category.
Source
The source document is
booklist.xml
.
Stylesheet
The stylesheet is
list-books.xsl
. It processes all the books in an
[./@category=current()/@category]
, which is true if the
category
attribute of the context element is the same as the
category
attribute of the current element. The context element is the one being tested; the element returned by
current()
is the one whose entry is being displayed. It also tests that these two elements are distinct elements, using the conditionnot(. is current()). In this case, you could also get away with writing.!=current(), which tests whether the two nodes have a different string value, but it can be a more expensive test, and it doesn't mean quite the same thing.
xmlns:xsl=“http://www.w3.org/1999/XSL/Transform”
version=“2.0”
xmlns:book=“books.uri”
exclude-result-prefixes=“book”
>
Category:
select=“$categories/category
[@code=current()/@category]/@desc”/>
Output
The output of the transformation is as follows.
Number, the Language of Science
Category: Science
The Young Visiters
Category: Children's Fiction
When We Were Very Young
Category: Children's Fiction
Design Patterns
Category: Computing
current-date, current-dateTime, current-time
These three functions are used to obtain the current date, the current time, or both.
Signature
These functions take no arguments.
| Type | Meaning | |
| Result | xs:date, xs:dateTime, or xs:time | The current date, dateTime, or time |
Effect
The current date and time forms part of the runtime context of an XPath expression. It will normally be taken from the system clock.
The resulting value will always have an explicit timezone component. The timezone will be taken from the implicit timezone provided by the evaluation context. In practice, this means it will probably be derived from the system default timezone for the machine on which the XSLT processor is running, or from the profile of the particular user.
In XSLT 2.0 it is defined that multiple calls on
current-dateTime()
and the other two functions will return the same result every time they are called within a single transformation. This means you can't call the function at the beginning and the end of the transformation to measure the elapsed time. The reason for this rule is that XSLT is rather purist about being a strictly functional language, and in a strictly functional language, calling the same function twice with the same arguments always returns the same result. This property makes life much simpler for optimizers.
In XQuery 1.0, the same rule applies to multiple calls within a single query.
Examples
| Expression | Possible Result |
| current-date() | An xs:date , say 2008-06-02Z |
| current-dateTime() | An xs:dateTime , say 2008-06-02T12:35:02-05:00 |
| current-time() | An xs:time , say 12:35:02Z |
