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https://issues.apache.org/jira/browse/FLINK-3557?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15173708#comment-15173708
]
ASF GitHub Bot commented on FLINK-3557:
---------------------------------------
Github user tillrohrmann commented on a diff in the pull request:
https://github.com/apache/flink/pull/1748#discussion_r54562674
--- Diff:
flink-streaming-scala/src/test/scala/org/apache/flink/streaming/api/scala/WindowFoldITCase.scala
---
@@ -70,7 +70,7 @@ class WindowFoldITCase extends
StreamingMultipleProgramsTestBase {
source1
.keyBy(0)
.window(TumblingEventTimeWindows.of(Time.of(3,
TimeUnit.MILLISECONDS)))
- .fold(("R:", 0), { (acc: (String, Int), v: (String, Int)) => (acc._1
+ v._1, acc._2 + v._2) })
+ .fold(("R:", 0)){ (acc: (String, Int), v: (String, Int)) => (acc._1
+ v._1, acc._2 + v._2) }
--- End diff --
I have no strong preference here. I didn't introduce them initially because
you also don't insert a space between a function name and the first parameter
list. But if you think that it's better, I'll change it.
> 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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