YPath, ZPath?

Dear colleagues,

the navigation model of XPath - navigation viewed as a sequence of steps, a step viewed as a combination of navigation axis, node test and optional predicates  - enables the expression of item selection in a clear, concise and very readable way. But I do not think that the basic principles of the navigation model depend on XML trees, rather, that variations of the XPath model could be designed for other kinds of tree-structured information.

Yet the only attempt to do so which I am aware of is JSONPath.

I would be interested in learning about other approaches to apply XPath-like navigation to non-XML structures - can you help me discover them?

And do you have thoughts about why one should not - or should - attempt such approaches?

With kind regards,

Hans-Juergen