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https://issues.apache.org/jira/browse/TINKERPOP-968?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15128230#comment-15128230
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Daniel Kuppitz commented on TINKERPOP-968:
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I'm fine with the addition of an {{optional()}} method that is implemented as
{{coalesce(traversal, identity)}}.
{code}
public default <E2> GraphTraversal<S, E2> optional(final Traversal<?, E2>
optionalTraversal) {
return this.coalesce(optionalTraversal, __.identity());
}
{code}
> Add first class support for an optional traversal
> -------------------------------------------------
>
> Key: TINKERPOP-968
> URL: https://issues.apache.org/jira/browse/TINKERPOP-968
> Project: TinkerPop
> Issue Type: Improvement
> Components: process
> Affects Versions: 3.1.0-incubating
> Reporter: pieter martin
>
> Both SparQL and Cypher use the "Optional" keyword to indicate an optional
> traversal. SQL uses the "left join".
> Gremlin has no first class support for an optional traversal. It can be
> achieved with the choose step but it is verbose, unintuitive and not what the
> choose step is intended for.
> The benefits of optional traversals are many. In particular it makes it
> trivial to load complete subgraphs/trees with one easy to read intuitive
> gremlin statement.
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