Recommit changing List.skip/take/revert returns Iterable and remove mappedBy.

tests/corelib/list_map_test.dart

+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+
+main() {
+  testOperations();
+}
+
+class ThrowMarker {
+  const ThrowMarker();
+  String toString() => "<<THROWS>>";
+}
+
+void testOperations() {
+  // Comparison lists.
+  List l = const [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+  List r = const [10, 9, 8, 7, 6, 5, 4, 3, 2, 1];
+  // Function that reverses l and r lists when used to map.
+  int rev(x) => 11 - x;
+  // A base list that starts out like l, but isn't const.
+  Iterable base = l.map((x) => x).toList();
+
+  Iterable reversed = l.map(rev);
+
+  Expect.listEquals(r, l.map(rev).toList());
+  Expect.listEquals(l, l.map(rev).map(rev).toList());
+  for (int i = 0; i < r.length; i++) {
+    Expect.equals(r[i], reversed.elementAt(i));
+  }
+  Expect.equals(4, base.indexOf(5));
+  Expect.equals(5, reversed.toList().indexOf(5));
+
+  // Reversed followed by combinations of skip and take.
+  List subr = [8, 7, 6, 5, 4, 3];
+  Expect.listEquals(subr, reversed.skip(2).take(6).toList());
+  Expect.listEquals(subr, reversed.take(8).skip(2).toList());
+  Expect.listEquals(subr,
+      reversed.toList().reversed.skip(2).take(6).toList().reversed.toList());
+  Expect.listEquals(subr,
+      reversed.toList().reversed.take(8).skip(2).toList().reversed.toList());
+  Expect.listEquals(subr,
+      reversed.take(8).toList().reversed.take(6).toList().reversed.toList());
+  Expect.listEquals(subr,
+      reversed.toList().reversed.take(8).toList().reversed.take(6).toList());
+  Expect.listEquals(subr,
+      reversed.toList().reversed.skip(2).toList().reversed.skip(2).toList());
+  Expect.listEquals(subr,
+      reversed.skip(2).toList().reversed.skip(2).toList().reversed.toList());
+
+
+  void testList(List list) {
+    var throws = const ThrowMarker();
+    List mappedList = new List(list.length);
+    for (int i = 0; i < list.length; i++) {
+      mappedList[i] = rev(list[i]);
+    }
+    Iterable reversed = list.map(rev);
+
+    void testEquals(v1, v2, path) {
+      if (v1 is Iterable) {
+        Iterator i1 = v1.iterator;
+        Iterator i2 = v2.iterator;
+        int index = 0;
+        while (i1.moveNext()) {
+          Expect.isTrue(i2.moveNext(),
+              "Too few actual values. Expected[$index] == ${i1.current}");
+          testEquals(i1.current, i2.current, "$path[$index]");
+          index++;
+        }
+        if (i2.moveNext()) {
+          Expect.fail(
+              "Too many actual values. Actual[$index] == ${i2.current}");
+        }
+      } else {
+        Expect.equals(v1, v2, path);
+      }
+    }
+
+    void testOp(operation(Iterable mappedList), name) {
+      var expect;
+      try {
+        expect = operation(mappedList);
+      } catch (e) {
+        expect = throws;
+      }
+      var actual;
+      try {
+        actual = operation(reversed);
+      } catch (e) {
+        actual = throws;
+      }
+      testEquals(expect, actual, "$name: $list");
+    }
+    testOp((i) => i.first, "first");
+    testOp((i) => i.last, "last");
+    testOp((i) => i.single, "single");
+    testOp((i) => i.firstMatching((n) => false), "firstMatching<false");
+    testOp((i) => i.firstMatching((n) => n < 10), "firstMatching<10");
+    testOp((i) => i.firstMatching((n) => n < 5), "firstMatching<5");
+    testOp((i) => i.firstMatching((n) => true), "firstMatching<true");
+    testOp((i) => i.lastMatching((n) => false), "lastMatching<false");
+    testOp((i) => i.lastMatching((n) => n < 5), "lastMatching<5");
+    testOp((i) => i.lastMatching((n) => n < 10), "lastMatching<10");
+    testOp((i) => i.lastMatching((n) => true), "lastMatching<true");
+    testOp((i) => i.singleMatching((n) => false), "singleMatching<false");
+    testOp((i) => i.singleMatching((n) => n < 5), "singelMatching<5");
+    testOp((i) => i.singleMatching((n) => n < 10), "singelMatching<10");
+    testOp((i) => i.singleMatching((n) => true), "singleMatching<true");
+    testOp((i) => i.contains(5), "contains(5)");
+    testOp((i) => i.contains(10), "contains(10)");
+    testOp((i) => i.any((n) => n < 5), "any<5");
+    testOp((i) => i.any((n) => n < 10), "any<10");
+    testOp((i) => i.every((n) => n < 5), "every<5");
+    testOp((i) => i.every((n) => n < 10), "every<10");
+    testOp((i) => i.max(), "max");
+    testOp((i) => i.min(), "min");
+    testOp((i) => i.reduce(0, (a, b) => a + b), "reduce-sum");
+    testOp((i) => i.join("-"), "join-");
+    testOp((i) => i.join(""), "join");
+    testOp((i) => i.join(), "join-null");
+    testOp((i) => i.map((n) => n * 2), "map*2");
+    testOp((i) => i.where((n) => n < 5), "where<5");
+    testOp((i) => i.where((n) => n < 10), "where<10");
+    testOp((i) => i.expand((n) => []), "expand[]");
+    testOp((i) => i.expand((n) => [n]), "expand[n]");
+    testOp((i) => i.expand((n) => [n, n]), "expand[n, n]");
+    testOp((i) => i.take(0), "take(0)");
+    testOp((i) => i.take(5), "take(5)");
+    testOp((i) => i.take(10), "take(10)");
+    testOp((i) => i.take(15), "take(15)");
+    testOp((i) => i.skip(0), "skip(0)");
+    testOp((i) => i.skip(5), "skip(5)");
+    testOp((i) => i.skip(10), "skip(10)");
+    testOp((i) => i.skip(15), "skip(15)");
+    testOp((i) => i.takeWhile((n) => false), "takeWhile(t)");
+    testOp((i) => i.takeWhile((n) => n < 5), "takeWhile(n<5)");
+    testOp((i) => i.takeWhile((n) => n > 5), "takeWhile(n>5)");
+    testOp((i) => i.takeWhile((n) => true), "takeWhile(f)");
+    testOp((i) => i.skipWhile((n) => false), "skipWhile(t)");
+    testOp((i) => i.skipWhile((n) => n < 5), "skipWhile(n<5)");
+    testOp((i) => i.skipWhile((n) => n > 5), "skipWhile(n>5)");
+    testOp((i) => i.skipWhile((n) => true), "skipWhile(f)");
+  }
+
+  // Combinations of lists with 0, 1 and more elements.
+  testList([]);
+  testList([0]);
+  testList([10]);
+  testList([0, 1]);
+  testList([0, 10]);
+  testList([10, 11]);
+  testList([0, 5, 10]);
+  testList([10, 5, 0]);
+  testList([0, 1, 2, 3]);
+  testList([3, 4, 5, 6]);
+  testList([10, 11, 12, 13]);
+  testList(l);
+  testList(r);
+  testList(base);
+
+  // Reverse const list.
+  Expect.listEquals(r, l.map(rev).toList());
+}