Async/Await feature in Dart 1.8

问题

Is it in the 1.8 release as an experimental feature like enum or is it not? And how can I use it in the Dart Editor? Is there a nice article or example app that can get me started with this?

When it is still an experimental feature what is recommended for pub packages? Is it fine to use that feature in pub packages or not?

回答1:

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';

来源：https://stackoverflow.com/questions/27212220/async-await-feature-in-dart-1-8