attribute attribute-name (of element-expression)? indexer
You can access the value of an XML or SGML attribute using the
Attribute references are always treated as string expressions, even if the attribute was declared in the SGML document to be of type NUMBER. However, string expressions which contain a valid representation of a decimal number can be used anywhere where a numeric expression is permitted, so this interpretation places no restriction on the use of attributes.
Attributes can always be further identified by following the attribute name with an element qualifier.
external-data-entity rule, unqualified attributes are data attributes; in other
contexts, they are attributes of the current element.
An item-based indexer can be used if the attribute was declared as a list-valued attribute. However,
unlike shelves, for which the
lastmost value is selected unless indicated otherwise, attributes do not
have a default selected value: if no indexer is specified, the whole attribute value is either tested
or is output as a single unit.
Attribute references provide the attribute value unmodified, except for:
delimiterdeclaration (which is, by default, a single space) to separate the tokens of a list-value attribute.
translate rule processing is not performed on the value of an attribute when it is
referenced using the
attribute herald. This contrasts with references to an attribute value using
the "%v" modifier.
Attempting to access an
attribute will cause an error:
#current(and no previous occurrence of an element named in the same declaration gave the attribute a value).
When using an element-expression the programmer should be aware that:
of elementqualifier is usually not needed, since, in most contexts, unqualified attributes are assumed to be attributes of the current element. In
external-data-entityrules, however, attributes by default are assumed to be data attributes. In that context, the
of elementqualifier is significant.
of open elementqualifiers refer to the specified ancestor that was most recently opened (the one the fewest "generations" removed from the current element).
of open elementqualifiers can list several element names.
In the header and body of an
external-data-entity rule, all unqualified references to attributes
actually refer to data attributes of the external entity being processed. In all other rules, they refer to
element attributes (attributes of element start tags).
Unqualified references to attributes inside functions always refer to element attributes. In order to refer to
the data attributes of an external entity being processed, the qualifier
of entity must be
Element qualifiers can themselves be qualified.
attribute "indent" of ancestor ("numlist" | "bullist" | "deflist")
Specifically, this line of code refers to the
indent attribute of a containing
deflist, whichever comes first, searching outwards
from the current element. Note that an error would result if the first element encountered did not have a value
specified for the
The following example illustrates how element qualifiers can be used with attribute references. By using the
of ancestor, this line of code refers to the
date attribute of an
enclosing element whose name is
attribute "date" of ancestor "change"