That does look promising and stirs curiosity. But while you are at it, could you not - at least, in principle - do it exactly the other way around - rather than define representations of flatMap() as /, etc., define a translation of / into flatMap(), etc - in short, a compilation of XPath into your low-level, streaming API expressions? Per mainstream, Java people are using a JAXB compilation step in their build processes anyway, adding an XPath compilation step would not hurt at all, and safety is at its maximum, as is expressiveness.