groovy-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Jesper Steen Møller <jes...@selskabet.org>
Subject Lambda vs. Closure (was: [VOTE] Apache Groovy Roadmap)
Date Tue, 07 Feb 2017 15:09:57 GMT
(changing the subject so we don't disrupt the main discussion)

Not quite 😔

The changes in Java to support Lambdas are much deeper than just how the Metafactory is invokedynamic'ed,
as it changes how type inference and overload resolution is done. Same as with the issues
we discussed a while back around method references: Supporting Java8 semantics in the Groovy
compiler is a very big task, as we just don't have the type information available.

I would much rather suggest supporting the lambda syntax with groovy semantics, but add warnings
if we detect that the code may rely on Java lambda semantics. For instance, we could warn
the user if the lambda referred to 'this' or 'super' directly.

-Jesper

> On 7 Feb 2017, at 16.00, Daniel Sun <realbluesun@hotmail.com> wrote:
> 
> Hi Jochen,
> 
>  
> 
> That’s great!
> 
> Paul and Graeme are both afraid of future breaking changes of groovy’s lambda expression,
which is currently based on closure. If we could generate *real* lambda bytecode for LambdaExpression,
groovy’s lambda expression will behave same with Java8’s at runtime😊
> 
>  
> 
> Cheers,
> 
> Daniel.Sun
> 
>  
> 
> 发件人: [hidden email] <x-msg://12/user/SendEmail.jtp?type=node&node=5738477&i=0>
> 发送时间: 2017年2月7日 22:23
> 收件人: [hidden email] <x-msg://12/user/SendEmail.jtp?type=node&node=5738477&i=1>
> 主题: Re: [VOTE] Apache Groovy Roadmap
> 
>  
> 
> 
> 
> On 07.02.2017 14:44, Daniel Sun wrote: 
> > Hi Cédric, 
> > 
> >       It seems that too many choices are a annoying problem, but I 
> > believe we can conquer it sooner or later ;) 
> >       BTW, is it possible to keep groovy' lambda expression as it 
> > is(i.e. groovy closure with lambda syntax) but generate *real* lambda 
> > bytecode for 
> > it(https://github.com/apache/groovy/blob/parrot/src/main/org/codehaus/groovy/ast/expr/LambdaExpression.java
<https://github.com/apache/groovy/blob/parrot/src/main/org/codehaus/groovy/ast/expr/LambdaExpression.java>)?

> 
> sure, you should make a visitLambdaExpression similar to 
> visitClosureExpression and change our visitors 
> 
> bye Jochen 
> 
> 
> If you reply to this email, your message will be added to the discussion below:
> http://groovy.329449.n5.nabble.com/VOTE-Apache-Groovy-Roadmap-tp5738250p5738471.html
<http://groovy.329449.n5.nabble.com/VOTE-Apache-Groovy-Roadmap-tp5738250p5738471.html>
> To unsubscribe from [VOTE] Apache Groovy Roadmap, click here <applewebdata://B43F076E-4CE3-48E5-BE21-FA7C074BC8FF>.
> NAML <http://groovy.329449.n5.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&id=instant_html%21nabble%3Aemail.naml&base=nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&breadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml>
> View this message in context: 答复: [VOTE] Apache Groovy Roadmap <http://groovy.329449.n5.nabble.com/VOTE-Apache-Groovy-Roadmap-tp5738250p5738477.html>
> Sent from the Groovy Dev mailing list archive <http://groovy.329449.n5.nabble.com/Groovy-Dev-f372993.html>
at Nabble.com.


Mime
View raw message