Used to construct arbitrary sequences. It may select any sequence of nodes and/or atomic values, and essentially adds these to the result sequence.
Available in XSLT 2.0 and later versions. Available in all Saxon editions.
- Category: instruction
- Content: sequence-constructor
- Permitted parent elements: any XSLT element whose content model is sequence-constructor; any literal result element
- Specifies the input. Mandatory attribute in XSLT 2.0, but in XSLT 3.0 (and implemented since Saxon 9.5) the input may be specified either by a
selectattribute, or by the enclosed sequence constructor.
xsl:sequence element may be used to produce any sequence of nodes and/or atomic values. These are included in the result sequence directly. Unlike
xsl:copy-of, no copy is made.
The most common use is to return a result from a function (see Example 1).
There are two other interesting usage scenarios. The first is copying atomic values into a tree (see Example 2). The second, more important, is constructing a sequence-valued variable (see Example 3). A variable is sequence-valued if the variable binding element (e.g.
xsl:variable) has non-empty content, an as attribute, and no
If nodes are constructed within a sequence-valued variable, they will be parentless. See Example 4 for an example of a sequence-valued variable containing parentless nodes.
Returning a result from a function:
<xsl:function name="f:increment" as="xs:integer"> <xsl:param name="in" as="xs:integer"/> <xsl:sequence select="$in + 1"/> </xsl:function>
Copying atomic values into a tree:
<e> <xsl:sequence select="1 to 5"/> <br/> <xsl:sequence select="6 to 10"/> </e>
This produces the output
<e>1 2 3 4 5<br/>6 7 8 9 10</e>.
Constructing a sequence-valued variable:
<xsl:variable name="seq" as="xs:integer *"> <xsl:for-each select="1 to 5">> <xsl:sequence select=". * ."/> </xsl:for-each/> </xsl:variable>
This produces the sequence (
1, 4, 9, 16, 25) as the value of the variable.
Creating a variable whose value is a sequence of three parentless attributes:
<xsl:variable name="seq" as="attribute() *"> <xsl:attribute name="a">10</xsl:attribute> <xsl:attribute name="b">20</xsl:attribute> <xsl:attribute name="a">30</xsl:attribute> </xsl:variable>
It is quite legitimate to have two attributes in the sequence with the same name; there is no conflict until an attempt is made to add them both to the same element. The attributes can be added to an element by using
<xsl:copy-of select="$seq"/> within an
xsl:element instruction or within a literal result element. At this stage the usual rule applies: if there are duplicate attributes, the last one wins.