Expressions
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4/8/2010
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 name space 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; it is an error for an expression to include a call to any other function.