Wire up Optional() for Gremlin API


#1

It looks like much of the code already exists, and the iterator is used for the MQL API already. I started looking at what would be required, but my brain is melting a little trying to onboard all the logic.

From: https://github.com/cayleygraph/cayley/issues/311


#2

Reopened, as it has a concrete implementation plan.


#3

#4