How to use multiple union step in gremlin query?

Question

I want to convert following cypher query in gremlin but facing issue while using union.

match d=(s:Group{id:123})<-[r:Member_Of*]-(p:Person) with d,
RELATIONSHIPS(d) as rels
WHERE NONE(rel in rels WHERE EXISTS(rel.`Ceased On`))
return *

UNION

match d=(s:Group{id:123})<-[r:Member_Of*]-(p:Group)-[r1:
Member_Of*]->(c:Group) with d,
RELATIONSHIPS(d) as rels
WHERE NONE(rel in rels WHERE EXISTS(rel.`Ceased On`))
return *

UNION

match d=(c:Group{id:123})-[r:Member_Of*]->(p:Group) with d,
RELATIONSHIPS(d) as rels
WHERE NONE(rel in rels WHERE EXISTS(rel.`Ceased On`))
return *

UNION

match d=(s:Group{id:123})<-[r:Member_Of*]-(p:Group)<-[r1:
Member_Of*]-(c:Person) with d,
RELATIONSHIPS(d) as rels
where NONE(rel in rels WHERE EXISTS(rel.`Ceased On`))
return *

In above cypher query, source vertex is Group, which has id '123', so for incoming and outgoing edge, I have created following gremlin query.

g.V().hasLabel('Group').has('id',123)
 union(
   __.inE('Member_Of').values('Name'), 
   __.outE('Member_Of').values('Name'))
.path()  

Now I have to traverse incoming edge for the vertex, which is incoming vertex for source vertex in above query, where I am confused with union syntax.

Please help, Thanks :)

Answer 1

Following is the total replacement of cypher query with gremlin query.

g.V().has('Group','id',123). //source vertex 
      union(
           //Following represent incoming Member_Of edge towards source vertex from Person Node, untill the last node in the chain
          repeat(inE('Member_Of').outV()).until(hasLabel('Person')),
          //Following represent incoming Member_Of edge from Group to source vertex and edge outwards from same Group, untill the last node in the chain
          repeat(inE('Member_Of').outV().hasLabel('Group').simplePath()).until(inE().count().is(0)).
              repeat(outE('Member_Of').inV().hasLabel('Group').simplePath()).until(inE().count().is(0)),
          //Following represent outgoing Member_Of edge from source vertex to another Group node, untill the last node in the chain
          repeat(outE('Member_Of').inV().hasLabel('Group').simplePath()).until(outE().count().is(0)),
          //Following represent incoming Member_Of edge from Group to source vertex and incoming edge from person to Group untill the last node in the chain
          repeat(inE('Member_Of').outV().hasLabel('Group').simplePath()).until(inE().count().is(0)).
              repeat(inE('Member_Of').outV().hasLabel('Person').simplePath()).until(inE().count().is(0))
      ).
      path().by(elementMap())