[NTG-context] a string xmlpath in Lua

Hello list, is there a Lua function to get the XML path of an element as a string? \xmlpath typesets the path, I need a similar function for Lua, but the path should be a string to be worked on in Lua. This is the problem originating that question: i must name (give an id to) some anonymous XML elements (read: "without an id attribute"), and their path is a good candidate. To be more precise: when i parse a <table> element, i look for elements representing footnotes, to prepare them with \setnotetext; then the table contents are parsed and the footnotes' markers are typeset with \note[footnote_id]. When there are more footnotes, i need to identify them, to give \note the right footnote id. Thanks, Massi