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Re: Why is that in JDK8: value used in lambda expression shuld be effectively final?

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On 05/01/13 09:50, Saxo wrote:
> Am Freitag, 4. Januar 2013 22:32:38 UTC+1 schrieb Steven Simpson:
>> On 03/01/13 14:45, Saxo wrote:
>>
>> I'm still interested in seeing an example that you would normally write
>> with free variables, demonstrating that lambdas are inadequate for the
>> things you'd like to do.
> Groovy:
>
> def list = [1, 2, 3]
> def sum = 0
> list.each { sum += it }
> println(sum)
>
> Kotlin:
>
> val list = arrayListOf(1, 2, 3)
> var sum = 0;
> list.forEach { i -> sum += i }
> println(sum)
>
> Scala:
>
> val list = List(1, 2, 3)
> var sum = 0        	
> list.foreach(sum += _)
> println(sum)

Sorry, but aren't these the same example that you originally gave, just 
in different languages?  I'm looking for different examples, perhaps 
expressed in a Java-like language with the features you were hoping for.


> Apparently, JDK8 lambdas can be assigned to a Runnable.

...if they take no arguments, returning nothing, and throw no checked 
exceptions.  Java lambdas don't have their own special function types, 
and have to be associated with a SAM type as soon as they are 
expressed.  Type inference is expected to make this implicit in most cases.

-- 
ss at comp dot lancs dot ac dot uk

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Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? jeti789@web.de - 2013-01-02 07:08 -0800
  Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? jeti789@web.de - 2013-01-02 07:52 -0800
  Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Steven Simpson <ss@domain.invalid> - 2013-01-02 17:33 +0000
    Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Saxo <jeti789@web.de> - 2013-01-02 11:31 -0800
      Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Lew <lewbloch@gmail.com> - 2013-01-02 12:52 -0800
        Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-01-02 20:58 -0400
          Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Lew <lewbloch@gmail.com> - 2013-01-02 17:40 -0800
            Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-01-03 20:43 -0400
        Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Saxo <jeti789@web.de> - 2013-01-02 23:44 -0800
          Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Patricia Shanahan <pats@acm.org> - 2013-01-03 07:57 -0800
            Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Lew <lewbloch@gmail.com> - 2013-01-03 13:22 -0800
              Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Patricia Shanahan <pats@acm.org> - 2013-01-03 16:14 -0800
      Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Steven Simpson <ss@domain.invalid> - 2013-01-02 21:46 +0000
        Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Lew <lewbloch@gmail.com> - 2013-01-02 17:35 -0800
        Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Saxo <jeti789@web.de> - 2013-01-03 02:13 -0800
          Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Saxo <jeti789@web.de> - 2013-01-03 06:45 -0800
            Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Steven Simpson <ss@domain.invalid> - 2013-01-04 21:32 +0000
              Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-04 14:38 -0800
                Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Steven Simpson <ss@domain.invalid> - 2013-01-04 23:45 +0000
                Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-04 17:24 -0800
                Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Steven Simpson <ss@domain.invalid> - 2013-01-05 13:20 +0000
              Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Saxo <jeti789@web.de> - 2013-01-05 01:50 -0800
                Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Steven Simpson <ss@domain.invalid> - 2013-01-05 11:21 +0000
                Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Saxo <jeti789@web.de> - 2013-01-05 04:27 -0800
                Re: Why is that in JDK8: value used in lambda expression shuld be effectively final? Steven Simpson <ss@domain.invalid> - 2013-01-05 12:58 +0000

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