Update 2
The most recent nightly build also supports async*
void main() {
generate().listen((i) => print(i));
}
Stream<int> generate () async* {
int i = 0;
for(int i = 0; i < 100; i++) {
yield ++i;
}
}
Update
yield
and yield*
in a method marked sync*
(returning an Iterable) are already supported in 1.9.0-edge.43534
void main() {
var x = concat([0, 1, 2, 3, 4], [5, 6, 7, 8, 9]);
// x is an Iterable which iterates over the values 1 to 9
print(x);
}
// A method marked `sync*` returns an `Iterable`
concat(Iterable left, Iterable right) sync* {
yield* left;
yield* right;
}
void main() {
print(filter([0, 1, 2, 3, 4, 5], (x) => x.isEven));
}
filter(ss, p) sync* {
for (var s in ss) {
if (p(s)) yield s;
}
}
async*
generator functions (returning a Stream) are not yet supported.
Original
Basic support is already available.
See https://www.dartlang.org/articles/await-async/ for more details.
main() async {
// await
print(await foo());
try {
print(await fooThrows());
} catch(e) {
print(e);
}
// await for
var stream = new Stream.fromIterable([1,2,3,4,5]);
await for (var e in stream) {
print(e);
}
}
foo() async => 42;
fooThrows() async => throw 'Anything';