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https://issues.apache.org/jira/browse/FLINK-3557?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15173883#comment-15173883
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ASF GitHub Bot commented on FLINK-3557:
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Github user tillrohrmann commented on the pull request:
https://github.com/apache/flink/pull/1748#issuecomment-190767633
Will be merging to master and release branch.
> Scala DataStream fold method should take fold function in secondary parameter
> list
> ----------------------------------------------------------------------------------
>
> Key: FLINK-3557
> URL: https://issues.apache.org/jira/browse/FLINK-3557
> Project: Flink
> Issue Type: Improvement
> Components: DataStream API, Scala API
> Affects Versions: 1.0.0
> Reporter: Till Rohrmann
> Assignee: Till Rohrmann
> Priority: Minor
>
> The current Scala DataStream API offers a {{fold}} method. The {{fold}}
> method takes two parameters, the initial value and the fold function.
> However, both parameters are specified in the same parameter list. This makes
> it clumsy to provide a multi-line anonymous function as the fold function
> parameter in Scala. One would have to wrap the function in an additional pair
> of curly braces. This could be avoided by having a second parameter list
> which takes the fold function. This would, additionally, be consistent with
> Scala's collection API.
> Old style
> {code}
> windowedStream.fold(("R:", 0), { (acc: (String, Int), v: (String, Int)) =>
> (acc._1 + v._1, acc._2 + v._2) })
> {code}
> vs. new style
> {code}
> windowedStream.fold(("R:", 0)){ (acc, v) => (acc._1 + v._1, acc._2 + v._2) }
> {code}
> These changes are API breaking.
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