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https://issues.apache.org/jira/browse/TINKERPOP-3184?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18016811#comment-18016811
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Taylor Riggan commented on TINKERPOP-3184:
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How is this different from the current support of using from() or to() as a
modulator for path()?
Example graph:
{{g.addV('Person').property('name','John').as('a').}}
{{ addV('Place').property('city','New York').as('b').}}
{{ addV('Thing').property('type','car').as('c').}}
{{ addE('visited').from('a').to('b').}}
{{ addE('has').from('b').to('c')}}
Query:
{{g.V().hasLabel('Person','name','John').}}
{{ outE('visited').inV().as('start').}}
{{ outE('has').inV().}}
{{ path().from('start').by(label)}}
Result:
{{path[Place, has, Thing]}}
> Please allow the path() step to take an optional from and to label
> ------------------------------------------------------------------
>
> Key: TINKERPOP-3184
> URL: https://issues.apache.org/jira/browse/TINKERPOP-3184
> Project: TinkerPop
> Issue Type: Wish
> Affects Versions: 3.7.4
> Reporter: Martin Häusler
> Priority: Major
>
> Hello,
> I am once again dealing with paths. I noticed that it is currently possible
> to do the following:
> {code:java}
> traversal().V()
> // ... navigation...
> .path()
> .unfold()
> {code}
> ... which is very neat. I was wondering if I can also get the path between a
> label and the current vertex. Turns out, I can:
> {code:java}
> traversal().V()
> // ... navigation ...
> .as("from")
> // ... navigation...
> .flatMap ( t-> t.path().subPath("from", null).iterator())
> {code}
> That is very useful! But it's a shame that the functionality is locked behind
> a lambda expression, which is not available in all scenarios. Moreover,
> gremlin optimizes away the path information tracking if no "path()" step is
> used in the query, so the lambda solution always requires some additional
> artificial steps on top.
> My proposal would be to add the following overload to the "path()" method:
> {code:java}
> public default GraphTraversal<S, Path> path(String fromLabel, String toLabel)
> {code}
> ... which behaves exactly like the lambda above. Both "fromLabel" and
> "toLabel" should accept NULL (same as "subPath(...)") which means start/end
> of the path respectively. Therefore calling "path()" would be the same as
> "path(null, null)".
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