I found this post, namely, this Gremlin query at the end of the post:
g.V.as('all').out.in.as('parents').optional('all').except('parents')
This query finds all orphaned nodes (or at least it should). I need to do this in Cayley (google's Golang graph database) but it doesn't work with Cayley's version of Gremlin (which is not truly Gremlin). Since there are various commands that are missing from Cayley's version I am unable to run the query against a Cayley graph. How would I go about writing a query that find all orphaned nodes like this with Cayley-gremlin's limited set of commands? Is it possible?