Accessing non-final local variables from a lambda expression

[Lawrence Kesteloot]

> In BGGA, CfJ, and other languages with lambdas, one could write it
> simply like this
>
> <T> Iterable<T> everyOther(Iterable<T> input) {
>    boolean flag = true;
>    return filter(input, (T t)->(flag ^= true));
> }
>
> But project lambda forbids access to mutable local variables from the
> enclosing scope.

<T> Iterable<T> everyOther(Iterable<T> input) {
   final boolean[] flag = new boolean[] { true };
   return filter(input, (T t)->(flag[0] ^= true));
}

It's not beautiful, but not the end of the world either. And the
performance is comparable, since in any case you have to create and
dereference some heap object.

Lawrence