First take on custom call generators.

test/mjsunit/array-push.js

+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Check pushes with various number of arguments.
+(function() {
+  var a = [];
+  for (var i = 0; i < 7; i++) {
+    a = [];
+
+    assertEquals(0, a.push());
+    assertEquals([], a, "after .push()");
+
+    assertEquals(1, a.push(1), "length after .push(1)");
+    assertEquals([1], a, "after .push(1)");
+
+    assertEquals(3, a.push(2, 3), "length after .push(2, 3)");
+    assertEquals([1, 2, 3], a, "after .push(2, 3)");
+
+    assertEquals(6, a.push(4, 5, 6),
+      "length after .push(4, 5, 6)");
+    assertEquals([1, 2, 3, 4, 5, 6], a,
+      "after .push(4, 5, 5)");
+
+    assertEquals(10, a.push(7, 8, 9, 10),
+      "length after .push(7, 8, 9, 10)");
+    assertEquals([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], a,
+      "after .push(7, 8, 9, 10)");
+
+    assertEquals(15, a.push(11, 12, 13, 14, 15),
+      "length after .push(11, 12, 13, 14, 15)");
+    assertEquals([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15], a,
+      "after .push(11, 12, 13, 14, 15)");
+
+    assertEquals(21, a.push(16, 17, 18, 19, 20, 21),
+      "length after .push(16, 17, 18, 19, 20, 21)");
+    assertEquals([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21], a,
+      "after .push(16, 17, 18, 19, 20, 21)");
+
+    assertEquals(28, a.push(22, 23, 24, 25, 26, 27, 28),
+      "length hafter .push(22, 23, 24, 25, 26, 27, 28)");
+    assertEquals([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28], a,
+      "after .push(22, 23, 24, 25, 26, 27, 28)");
+  }
+})();