Broken XPath queries

[bbonf]

We've received two queries from Aleksei that don't work at all (but they do work with Gretel4):

//node[@cat="inf" and not(@rel="vc" and ../node[@pt="ww" and @rel="hd"]/@lemma="zullen") and not(@rel="cnj" and ../node[node[@rel="vc"]] and ../../node[@pt="ww" and @rel="hd"]/@lemma="zullen") and ((@rel="cnj" and ../../node[@pt="ww" and @rel="hd"] and not(../../@cat="smain" or ../../@cat="sv1")) or (../node[@pt="ww" and @rel="hd"] and not(../@cat="smain" or ../@cat="sv1"))) and node[@rel="svp" and @pt="vz"] and node[@rel="hd" and @pt="ww" and number(@begin) > ../node[@rel="svp" and @pt="vz"]/number(@end) and not(@begin = ancestor::node/node[@lemma="te"]/@end)] and node[@rel="hd" and @pt="ww"]]

//node[not(@cat="smain" or @cat="sv1") and not(@cat="inf" and @rel="vc" and ../node[@pt="ww" and @rel="hd"]/@lemma="zullen") and not(@cat="inf" and @rel="cnj" and ../node[node[@rel="vc"]] and ../../node[@pt="ww" and @rel="hd"]/@lemma="zullen") and not(@cat="ppart" and @rel="vc") and not(@cat="ppart" and @rel="cnj" and ../node[node[@rel="vc"]]) and node[@rel="hd" and @pt="ww"] and node[@cat="pp" and number(@begin) < ../node[@pt="ww" and @rel="hd"]/number(@begin) and node[@rel="hd"]] and not(node[@cat="pp" and number(@end) > ../node[@pt="ww" and @rel="hd"]/number(@end)])]

[bbonf]

This is failing because lxml doesn't like these XPath expressions, see https://github.com/UUDigitalHumanitieslab/gretel-django/blob/develop/backend/search/basex_search.py#L19

[bbonf]

A possible workaround is to let "advanced users" skip the validation step

[bbonf]

Consider https://github.com/ekaats/xpyth_parser for validation