XPath/XQuery base-uri function


Returns the base URI of a node.


) as xs:anyURI?
$arg as node()?
) as xs:anyURI?


The zero-argument form of this function is deterministic, context-dependent, and focus-dependent.
The one-argument form of this function is deterministic, context-independent, and focus-independent.


The zero-argument version of the function returns the base URI of the context node: it is equivalent to calling fn:base-uri(.).

The single-argument version of the function behaves as follows:

  1. If $arg is the empty sequence, the function returns the empty sequence.
  2. Otherwise, the function returns the value of the dm:base-uri accessor applied to the node $arg. This accessor is defined, for each kind of node, in the XDM specification (See ).
As explained in XDM, document, element and processing-instruction nodes have a base-uri property which may be empty. The base-uri property for all other node kinds is the empty sequence. The dm:base-uri accessor returns the base-uri property of a node if it exists and is non-empty; otherwise it returns the result of applying the dm:base-uri accessor to its parent, recursively. If the node does not have a parent, or if the recursive ascent up the ancestor chain encounters a parentless node whose base-uri property is empty, the empty sequence is returned. In the case of namespace nodes, however, the result is always an empty sequence — it does not depend on the base URI of the parent element.

See also fn:static-base-uri.

Error Conditions

The following errors may be raised when $arg is omitted:

If the context item is absent, dynamic error

If the context item is not a node, type error .