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Posted to issues@flink.apache.org by "Till Rohrmann (JIRA)" <ji...@apache.org> on 2016/03/01 12:36:18 UTC
[jira] [Updated] (FLINK-3557) Scala DataStream fold method should
take fold function in secondary parameter list
[ https://issues.apache.org/jira/browse/FLINK-3557?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Till Rohrmann updated FLINK-3557:
---------------------------------
Description:
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.
was:
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: (String, Int), v: (String, Int)) => (acc._1 + v._1, acc._2 + v._2) }
{code}
These changes are API breaking.
> 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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