FOXpath - an expression language for selecting files and folders

A new expression language (FOXpath, short for folder XPath) enables XPath-like addressing of files and folders in a file system. The first version of the language is a modified copy of XPath 3.0, with node navigation removed and file system navigation added. The language is based on the data model XDM 3.0, without assuming any modifications of the model. In a second step, the language was merged back into XPath 3.0, resulting in FOXpath 3.0, which is a superset of XPath 3.0. The new expression language supports node navigation, file system navigation and a free combination of both functionalities within a single path expression. A reference implementation is described, and the possibility of extending the new functionality beyond file systems is discussed.