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https://issues.apache.org/jira/browse/TINKERPOP-1628?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16448599#comment-16448599
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ASF GitHub Bot commented on TINKERPOP-1628:
-------------------------------------------
Github user spmallette commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/844#discussion_r183485753
--- Diff: docs/src/reference/the-traversal.asciidoc ---
@@ -2338,6 +2338,22 @@
g.V(1).as("a").repeat(out().as("a")).times(2).select(last, "a")
g.V(1).as("a").repeat(out().as("a")).times(2).select(all, "a")
----
+In addition to the previously shown examples, where `select()` was used to
select an element based on a static key, `select()` can also accept a traversal
+that emits a key.
+
+WARNING: Since the key used by `select(<traversal>)` cannot be determined
at compile time, the `TraversalSelectStep` enables full path tracking.
+
+[gremlin-groovy,modern]
+----
+g.withSideEffect("alias", ["marko":"okram"]).V(). <1>
+ values("name").sack(assign). <2>
+ optional(select("alias").select(sack())) <3>
+----
+
+<1> Inject a name alias map and start the traversal from all vertices.
+<2> Select all `name` values and store them as the current traverser's
sack value.
+<3> Optionally select the alias for the current name from the injected map.
+
--- End diff --
please add the two new `select()` methods to the list of "Additional
References" below.
> Implement TraversalSelectStep
> -----------------------------
>
> Key: TINKERPOP-1628
> URL: https://issues.apache.org/jira/browse/TINKERPOP-1628
> Project: TinkerPop
> Issue Type: Improvement
> Components: process
> Affects Versions: 3.3.0
> Reporter: Daniel Kuppitz
> Assignee: Daniel Kuppitz
> Priority: Major
>
> It should be possible to have nested {{select()}} or rather to select dynamic
> keys.
> {noformat}
> gremlin> aliases = ["marko":"okram"]
> gremlin> g.withSideEffect("a", aliases).V().hasLabel("person").
> values("name").as("n").
> optional(select("a").select(select("n")))
> ==>okram
> ==>vadas
> ==>josh
> ==>peter
> {noformat}
> I know there are more steps that could / should allow traversals, but to me
> {{select()}} seems to be the most important one (perhaps because the
> workaround is / can be super expensive).
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