[thechao]

There is a fairly straightforward generalization of the 'axis' concept to allow graph traversal: 'GPath'. (You have to add an annotation for a traversal kind, and an identifier for a property map.) XPath can be straightforwardly desugared to GPath. I implemented this years ago for an EDG IPR[1] back-end, hooked up a number of 'standard queries' over C++ to Todd Veldhuizen's live OpenGL force-directed graph-viewer [2], and watched EDG compile code---pretty wild stuff watching expressions 'bloom', and classes 'become referenced', etc.

[1] https://parasol.tamu.edu/pivot/ [2] http://ubietylab.net