XPath 3.0 Conformance

Saxon 9.7 implements the XPath 3.0 specification as defined in the Recommendation of 8 April 2014.

The various Saxon editions implement XPath 3.0 capabilities as follows:

• Saxon-HE implements all XPath 3.0 features with the exception of schema awareness and support for higher-order functions.

• Saxon-PE adds support for higher-order functions. Specifically, this means inline function declarations, dynamic function calls, named function items (such as name#1), and functions that take functions as arguments or return functions as their result, for example fn:filter and fn:function-lookup.

• Saxon-EE adds support for schema awareness. This includes the ability to handle source documents that have type annotations resulting from schema validation, and the ability to use user-defined type names for example in an "instance of" expression.

New features in XPath 3.0 include the following:

• String contatenation operator ||

• Simple mapping operator !

• Casting is allowed from a string to a union or list type

• Union types, provided they meet certain rules, can be used as a SequenceType

• Dynamic function call (functions are first class values (items) in the data model)

• Function literals, for example substring#2

• Inline functions, for example function($i) {$i*$i}

• Partial application of functions, for example concat('$', ?)

• Let expressions, for example let $v := expr return f($v)

• EQNames (Q{uri}local) wherever QNames are allowed

In Saxon, maps are implemented (as an extenxion feature) in XPath 3.0 as described in the XSLT 3.0 specification (and XPath 3.1 specification). This is true whether or not the XPath processor is being invoked in an XSLT context. For details see Maps in XPath.

For details of the function library supported, see Functions.