Expressions

Expressions are used in XSL Transformations (XSLT) for the following purposes.

• Selecting nodes for processing.
• Specifying conditions for different ways of processing a node.
• Generating text to be inserted in the result tree.

Expressions occur as the value of certain attributes on XSLT-defined elements and within curly braces in attribute value templates.

Expression evaluation occurs with respect to a context. In XSLT, an outermost expression (that is, an expression that is not part of another expression) gets its context as follows.

• The context node comes from the current node.
• The context position comes from the position of the current node in the current node list; the first position is 1.
• The context size comes from the size of the current node list.
• The variable bindings are the bindings in scope on the element that has the attribute in which the expression occurs.
• The set of namespace declarations are those in scope on the element that has the attribute in which the expression occurs.
• The function library consists of those found at XPath Functions and any functions defined by a binding mechanism such as addObject Method or the msxsl:script Element. Calling a function with no corresponding binding is an error.

See Also

Patterns