Hi Maurizio, hi all,
The code below doesn't compile but I think it should.
[lambda.javac] ReducerBug.java:17: error: bad operand types for binary
operator '+'
[lambda.javac] int result = reduce(l, 0, #{ e, v -> e + v});
[lambda.javac] ^
[lambda.javac] first type: Integer
[lambda.javac] second type: V
[lambda.javac] where V is a type-variable:
[lambda.javac] V extends Object declared in interface Reducer
[lambda.javac] 1 error
I don't understand why V (which is a type variable of the interface) can
be propagated
in the body of the lambda thus I think it's a bug.
Rémi
public class ReducerBug {
interface Reducer<E, V> {
public V reduce(E element, V value);
}
private static <E> int reduce(Iterable<? extends E> iterable, int
initialValue, Reducer<? super E, Integer> reducer) {
int value = initialValue;
for(E e: iterable) {
value = reducer.reduce(e, value);
}
return value;
}
public static void main(String[] args) {
java.util.List<Integer> l = java.util.Arrays.asList(1, 2, 3);
int result = reduce(l, 0, #{ e, v -> e + v});
System.out.println(result);
}
}