Implement [Generator].prototype.return.

test/mjsunit/harmony/generators.js

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+
+{ // yield in try-catch
+
+  let g = function*() {
+    try {yield 1} catch (error) {assertEquals("caught", error)}
+  };
+
+  assertThrowsEquals(() => g().throw("not caught"), "not caught");
+
+  {
+    let x = g();
+    assertEquals({value: 1, done: false}, x.next());
+    assertEquals({value: undefined, done: true}, x.throw("caught"));
+  }
+
+  {
+    let x = g();
+    assertEquals({value: 1, done: false}, x.next());
+    assertEquals({value: undefined, done: true}, x.next());
+    assertThrowsEquals(() => x.throw("not caught"), "not caught");
+  }
+}
+
+
+{ // yield in try-finally, finally clause performs return
+
+  let g = function*() { try {yield 42} finally {return 13} };
+
+  { // "return" closes at suspendedStart
+    let x = g();
+    assertEquals({value: 666, done: true}, x.return(666));
+    assertEquals({value: undefined, done: true}, x.next(42));
+    assertThrowsEquals(() => x.throw(43), 43);
+    assertEquals({value: 42, done: true}, x.return(42));
+  }
+
+  { // "throw" closes at suspendedStart
+    let x = g();
+    assertThrowsEquals(() => x.throw(666), 666);
+    assertEquals({value: undefined, done: true}, x.next(42));
+    assertEquals({value: 43, done: true}, x.return(43));
+    assertThrowsEquals(() => x.throw(44), 44);
+  }
+
+  { // "next" closes at suspendedYield
+    let x = g();
+    assertEquals({value: 42, done: false}, x.next());
+    assertEquals({value: 13, done: true}, x.next(666));
+    assertEquals({value: undefined, done: true}, x.next(666));
+    assertThrowsEquals(() => x.throw(666), 666);
+  }
+
+  { // "return" closes at suspendedYield
+    let x = g();
+    assertEquals({value: 42, done: false}, x.next());
+    assertEquals({value: 13, done: true}, x.return(666));
+    assertEquals({value: undefined, done: true}, x.next(666));
+    assertEquals({value: 666, done: true}, x.return(666));
+  }
+
+  { // "throw" closes at suspendedYield
+    let x = g();
+    assertEquals({value: 42, done: false}, x.next());
+    assertEquals({value: 13, done: true}, x.throw(666));
+    assertThrowsEquals(() => x.throw(666), 666);
+    assertEquals({value: undefined, done: true}, x.next(666));
+  }
+}
+
+
+{ // yield in try-finally, finally clause doesn't perform return
+
+  let g = function*() { try {yield 42} finally {13} };
+
+  { // "return" closes at suspendedStart
+    let x = g();
+    assertEquals({value: 666, done: true}, x.return(666));
+    assertEquals({value: undefined, done: true}, x.next(42));
+    assertThrowsEquals(() => x.throw(43), 43);
+    assertEquals({value: 42, done: true}, x.return(42));
+  }
+
+  { // "throw" closes at suspendedStart
+    let x = g();
+    assertThrowsEquals(() => x.throw(666), 666);
+    assertEquals({value: undefined, done: true}, x.next(42));
+    assertEquals({value: 43, done: true}, x.return(43));
+    assertThrowsEquals(() => x.throw(44), 44);
+  }
+
+  { // "next" closes at suspendedYield
+    let x = g();
+    assertEquals({value: 42, done: false}, x.next());
+    assertEquals({value: undefined, done: true}, x.next(666));
+    assertEquals({value: undefined, done: true}, x.next(666));
+    assertThrowsEquals(() => x.throw(666), 666);
+    assertEquals({value: 42, done: true}, x.return(42));
+  }
+
+  { // "return" closes at suspendedYield
+    let x = g();
+    assertEquals({value: 42, done: false}, x.next());
+    assertEquals({value: 666, done: true}, x.return(666));
+    assertEquals({value: undefined, done: true}, x.next(666));
+    assertThrowsEquals(() => x.throw(44), 44);
+    assertEquals({value: 42, done: true}, x.return(42));
+  }
+
+  { // "throw" closes at suspendedYield
+    let x = g();
+    assertEquals({value: 42, done: false}, x.next());
+    assertThrowsEquals(() => x.throw(666), 666);
+    assertEquals({value: undefined, done: true}, x.next(666));
+    assertThrowsEquals(() => x.throw(666), 666);
+    assertEquals({value: 42, done: true}, x.return(42));
+  }
+}
+
+
+{ // yield in try-finally, finally yields and performs return
+
+  let g = function*() { try {yield 42} finally {yield 43; return 13} };
+
+  {
+    let x = g();
+    assertEquals({value: 42, done: false}, x.next());
+    assertEquals({value: 43, done: false}, x.return(666));
+    assertEquals({value: 13, done: true}, x.next());
+    assertEquals({value: 666, done: true}, x.return(666));
+  }
+
+  {
+    let x = g();
+    assertEquals({value: 666, done: true}, x.return(666));
+    assertEquals({value: undefined, done: true}, x.next());
+    assertEquals({value: 666, done: true}, x.return(666));
+  }
+}