Implement for-await-of statement. (#3946)

AsyncIteratorClose has not supported yet.

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com

tests/jerry/es.next/for-await-of.js

@@ -0,0 +1,198 @@
+// Copyright JS Foundation and other contributors, http://js.foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+function check_syntax_error (code)
+{
+  try {
+    eval (code);
+    assert (false);
+  } catch (e) {
+    assert (e instanceof SyntaxError);
+  }
+}
+
+check_syntax_error ("for await (a of b)");
+check_syntax_error ("async function f() { for await (a in b) ; }");
+check_syntax_error ("async function f() { for await ( ; ; ) ; }");
+check_syntax_error ("async function f() { for await (let a = 0; a < 4; a++) ; }");
+
+var successCount = 0;
+
+// Test 1
+
+var promise1 = Promise.resolve("Resolved");
+
+var asyncIter1 = {
+  [Symbol.asyncIterator]() {
+    var idx = 0;
+
+    function next() {
+      idx++;
+      if (idx == 1) {
+        return { value:"Val", done: false }
+      } else if (idx == 2) {
+        return { value:promise1, done: false }
+      } else if (idx == 3) {
+        return { value:4.5, done: false }
+      }
+      return { value:promise1, done: true }
+    }
+
+    successCount++
+    return { next }
+  }
+}
+
+function checkAsyncIter1(v, idx)
+{
+  if (idx === 1) {
+    assert(v === "Val")
+  } else if (idx === 2) {
+    assert(v === promise1)
+  } else if (idx === 3) {
+    assert(v === 4.5)
+  } else {
+    assert(false)
+  }
+}
+
+async function f1a() {
+  var idx = 0;
+  for await (var v of asyncIter1) {
+    checkAsyncIter1(v, ++idx);
+    successCount++;
+  }
+  successCount++;
+}
+
+f1a()
+
+async function f1b() {
+  await promise1
+
+  var idx = 0;
+  for await (var v of asyncIter1) {
+    checkAsyncIter1(v, ++idx);
+    successCount++;
+  }
+  successCount++;
+}
+
+f1b()
+
+async function *f1c() {
+  var idx = 0;
+  for await (var v of asyncIter1) {
+    checkAsyncIter1(v, ++idx);
+    successCount++;
+  }
+  successCount++;
+}
+
+f1c().next()
+
+async function *f1d() {
+  await promise1
+
+  var idx = 0;
+  for await (var v of asyncIter1) {
+    checkAsyncIter1(v, ++idx);
+    successCount++;
+  }
+  successCount++;
+}
+
+f1d().next()
+
+// Test 2
+
+var state2 = 0
+var promise2 = Promise.reject("Rejected");
+
+var asyncIter2 = {
+  [Symbol.asyncIterator]() {
+    var idx = 0;
+    assert(++state2 === 1)
+
+    function next() {
+      idx++;
+      if (idx == 1) {
+        assert(++state2 === 2)
+        return { value:"Str", done: false }
+      } else if (idx == 2) {
+        assert(++state2 === 4)
+        return { value:promise2, done: false }
+      } else if (idx == 3) {
+        assert(++state2 === 6)
+        return { value:-3.5, done: false }
+      }
+      assert(++state2 === 8)
+      return { value:promise2, done: true }
+    }
+
+    successCount++
+    return { next }
+  }
+}
+
+function checkAsyncIter2(v, idx)
+{
+  if (idx === 1) {
+    assert(v === "Str")
+  } else if (idx === 2) {
+    assert(v === promise2)
+  } else if (idx === 3) {
+    assert(v === -3.5)
+  } else {
+    assert(false)
+  }
+}
+
+async function *f2a() {
+  var idx = 0;
+  for await (var v of asyncIter2) {
+    checkAsyncIter2(v, ++idx)
+    yield v
+  }
+  successCount++;
+}
+
+async function f2b() {
+  var idx = 0;
+  var g = f2a();
+  var v;
+
+  while (true) {
+    v = await g.next()
+
+    if (v.done) {
+      break;
+    }
+
+    checkAsyncIter2(v.value, ++idx)
+    ++state2
+    assert(state2 === 3 || state2 === 5 || state2 === 7)
+  }
+
+  successCount++;
+}
+
+f2b();
+
+// END
+
+function __checkAsync() {
+  assert(state2 === 8)
+  assert(successCount === 23)
+}