XSL element attribute-set

Named Attribute Sets

<attribute-set>
  name = qname
  use-attribute-sets = qnames
Model: attribute*
</attribute-set>

The xsl:attribute-set element defines a named set of attributes. The name attribute specifies the name of the attribute set. The value of the name attribute is a QName, which is expanded as described in qname. The content of the xsl:attribute-set element consists of zero or more xsl:attribute elements that specify the attributes in the set.

Attribute sets are used by specifying a use-attribute-sets attribute on xsl:element, xsl:copy (see copying) or xsl:attribute-set elements. The value of the use-attribute-sets attribute is a whitespace-separated list of names of attribute sets. Each name is specified as a QName, which is expanded as described in qname. Specifying a use-attribute-sets attribute is equivalent to adding xsl:attribute elements for each of the attributes in each of the named attribute sets to the beginning of the content of the element with the use-attribute-sets attribute, in the same order in which the names of the attribute sets are specified in the use-attribute-sets attribute. It is an error if use of use-attribute-sets attributes on xsl:attribute-set elements causes an attribute set to directly or indirectly use itself.

Attribute sets can also be used by specifying an xsl:use-attribute-sets attribute on a literal result element. The value of the xsl:use-attribute-sets attribute is a whitespace-separated list of names of attribute sets. The xsl:use-attribute-sets attribute has the same effect as the use-attribute-sets attribute on xsl:element with the additional rule that attributes specified on the literal result element itself are treated as if they were specified by xsl:attribute elements before any actual xsl:attribute elements but after any xsl:attribute elements implied by the xsl:use-attribute-sets attribute. Thus, for a literal result element, attributes from attribute sets named in an xsl:use-attribute-sets attribute will be added first, in the order listed in the attribute; next, attributes specified on the literal result element will be added; finally, any attributes specified by xsl:attribute elements will be added. Since adding an attribute to an element replaces any existing attribute of that element with the same name, this means that attributes specified in attribute sets can be overridden by attributes specified on the literal result element itself.

The template within each xsl:attribute element in an xsl:attribute-set element is instantiated each time the attribute set is used; it is instantiated using the same current node and current node list as is used for instantiating the element bearing the use-attribute-sets or xsl:use-attribute-sets attribute. However, it is the position in the stylesheet of the xsl:attribute element rather than of the element bearing the use-attribute-sets or xsl:use-attribute-sets attribute that determines which variable bindings are visible (see variables); thus, only variables and parameters declared by top-level xsl:variable and xsl:param elements are visible.

The following example creates a named attribute set title-style and uses it in a template rule.

<xsl:template match="chapter/heading">
  <fo:block quadding="start" xsl:use-attribute-sets="title-style">
    <xsl:apply-templates/>
  </fo:block>
</xsl:template>

<xsl:attribute-set name="title-style">
  <xsl:attribute name="font-size">12pt</xsl:attribute>
  <xsl:attribute name="font-weight">bold</xsl:attribute>
</xsl:attribute-set>

Multiple definitions of an attribute set with the same expanded-name are merged. An attribute from a definition that has higher import precedence takes precedence over an attribute from a definition that has lower import precedence. It is an error if there are two attribute sets that have the same expanded-name and equal import precedence and that both contain the same attribute, unless there is a definition of the attribute set with higher import precedence that also contains the attribute. An XSLT processor may signal the error; if it does not signal the error, it must recover by choosing from amongst the definitions that specify the attribute that have the highest import precedence the one that was specified last in the stylesheet. Where the attributes in an attribute set were specified is relevant only in merging the attributes into the attribute set; it makes no difference when the attribute set is used.