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From Daniel Sun <realblue...@hotmail.com>
Subject [VOTE]About the implementation of lambda expression
Date Tue, 07 Feb 2017 16:20:11 GMT
Hi all,

      Jesper and I discussed the *real* lambda expression(i.e. Java8's
lambda expression) just now. As Jesper found, Java8's lambda expression is
implemented in Java as an invokedynamic call which makes use of a bootstrap
method calling into a class called the LambdaMetafactory
(https://docs.oracle.com/javase/8/docs/api/java/lang/invoke/LambdaMetafactory.html).
and puts the body of the lambda expression into a hidden method on the
class. The LambdaMetafactory sets up the magic class which holds any escaped
variables and implements the functional interface. To work, it requires
EXACT type information,* so it's only possible to do this in static
compilation*.

      Current lambda expression is based on closure, so it can work well in
the default mode and static compilation mode. But if we want the *real*
lambda expression, it will be only available in the static compilation
mode(as above said). When developers does not enable static compilation, we
provide them lambda expression based on closure or provide no lambda
expression at all? I prefer the universal version of lambda expression, i.e.
lambda expression based on closure with some warning(such as changing the
delegation strategy of 'this' is forbidden, reference:
http://groovy-lang.org/closures.html#_delegation_strategy)

- [ ] A, lambda expression based on closure with warning(or error prompt)
- [ ] B, *real* lambda expression is available *in the static compilation
mode* while lambda expression based on closure is available *in the default
mode*
- [ ] C, *real* lambda expression is only available *in the static
compilation mode* while *no lambda expression* is available *in the default
mode*

P.S. My vote is A

Cheers,
Daniel.Sun



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