XSLT Reference |  |
XSLT Reference | |
Sometimes you want to number things, like chapters in a book, or section numbers in an outline (1, 1.1, 1.2, and so on). That's what this element is for. It can also be used to format a number derived from an XPath expression.
The way elements are numbered depends on their
position in a node-set. For example, if you have an
element called <volume-set> whose children are
<volume> elements, the
template for the <volume-set> element will
probably use this construct to format its children:
<xsl:apply-templates select="volume"/>
The select="volume" XPath
expression produces a node-set containing the <volume> children. So, the
template that formats the <volume> element will get a node
whose position in that set can be determined with the
XPath function position(). Then you'll need
an <xsl:number>
construct to convert that position into a number in the
output.
This feature has a lot of attributes that let you control the format of the number, and even its value:
valueIf you just want to format the value of an XPath
expression, use this attribute with the expression as
its value. For example, <xsl:number
value="$bat-count"/> would output the value
of the bat-count variable. If
you want to number elements, though, don't use this
attribute.
countAn XPath pattern that selects the nodes that are
counted. For example, if you want your <theorem> and <lemma> tags to be
counted on the same system, you can specify
count="theorem|lemma".
levelThis attribute controls whether we are numbering elements at just one level, or at multiple levels at once (such as an outline that has numbers like “2.3.1.5”). Values are:
single | Only elements at the same level as the current node are counted. |
multiple | Any ancestor nodes that match the count
attribute are included to form a compount
number. For example, if the current node
is the 4th child of the 1st child of the
3rd child of its ancestor nodes that
match the count value,
the generated number will be 3.1.4. |
any | All the preceding and ancestor nodes
that match the count
expression are counted in a single
sequence, and the number output is in
that sequence. |
formatThe value of this attribute is a model for how the formatted number should look. Values include:
"1" | Use Arabic numerals. You can supply
leading zeroes if you like, so a value of
"001" would
fill each number with up to two leading
zeroes. |
"a" | Use lowercase letters. The sequence is a, b, c, ..., z, aa, ab, ... and so on. |
"A" | Use capital letters. |
"i" | Use lowercase Roman numerals. |
"I" | Use uppercase Roman numerals. |
You can also supply trailing punctuation, so
for example format="1:
" would follow each number with a colon
and space.
There are some other attributes, not discussed here, that are useful for non-USA usages. Refer to the XSLT specification for more details.