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From Guillaume Laforge <glafo...@gmail.com>
Subject Re: Lambda expression for Groovy 3
Date Tue, 18 Oct 2016 18:21:34 GMT
Is it actually Groovy closures? or "real" Java lambdas?

On Tue, Oct 18, 2016 at 7:42 PM, Jochen Theodorou <blackdrag@gmx.org> wrote:

>
> hah, I knew you can do it ;)
>
> On 18.10.2016 18:34, daniel_sun wrote:
>
>> Jochen, lambda expression is fully supported now :)
>>
>> https://github.com/danielsun1106/groovy-parser/commit/c380e4
>> 230ecef350855b9f56a220411635a7ff87
>>
>> https://github.com/danielsun1106/groovy-parser/blob/master/
>> src/test/resources/core/Lambda_01x.groovy
>>
>>
>> Cheers,
>> Daniel.Sun
>>
>>
>>
>> 在 "Jochen Theodorou [via Groovy]" <ml-node+[hidden email]
>> </user/SendEmail.jtp?type=node&node=5736176&i=0>>,2016年10月18日
00:37
>>
>> 写道:
>>
>>
>>
>>     On 17.10.2016 17:40, daniel_sun wrote:
>>      > Hi all,
>>      >
>>      >        Lambda expression for Groovy has been completed with a
>> little
>>      > limitation, which is due to the existing closure whose parameter
>>     list can be
>>      > ambiguous to lambda expression, e.g. {a -> a} which can be parsed
>>     as a
>>      > lambda expression in a block, but we expect it a closure.
>>
>>     I think that limitation is ok
>>
>>      > In order to
>>      > resolve the ambiguities, the parentheses for parameters is a
>>     must, e.g.
>>      > *Java8* allows parentheses-less parameter for lambda when the
>>     parameter is
>>      > single and without type: e -> e, but *Groovy* only allows
>>     parameter with
>>      > parentheses: (e) -> e.
>>      >
>>      >        *Here are some examples for lambda expression for Groovy:*
>>      > assert 9 == [1, 2, 3].stream().map((e) -> e + 1).reduce(0, (r, e)
>>     -> r + e)
>>
>>     which means you cannot write
>>      > assert 9 == [1, 2, 3].stream().map(e -> e + 1).reduce(0, (r, e)
>>     -> r + e)
>>
>>     which I find not so ok. Here again it would be no problem if it is
>>     recognized as Closure if that is more easy to accomplish.
>>
>>     bye Jochen
>>
>>
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>
>


-- 
Guillaume Laforge
Apache Groovy committer & PMC Vice-President
Developer Advocate @ Google Cloud Platform

Blog: http://glaforge.appspot.com/
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