Migrate language block 46 - canonical_const ... char_escape.

tests/language_strong/cascade_precedence_test.dart

-// Copyright (c) 2011, 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.
-
-import "package:expect/expect.dart";
-
-class A {
-  int value;
-  A(this.value);
-  void set(int value) {
-    this.value = value;
-  }
-
-  int get() => value;
-  int operator [](int index) => value + index;
-  void operator []=(int index, int newValue) {
-    value += -index + newValue;
-  }
-
-  void test(int expected) {
-    Expect.equals(expected, value);
-  }
-
-  Function limp(int n) {
-    if (n == 0) return set;
-    return () => limp(n - 1);
-  }
-
-  A get self => this;
-  A operator +(A other) {
-    this.value += other.value;
-    return this;
-  }
-}
-
-class Box {
-  A value;
-  Box(this.value);
-  A operator [](int pos) => value;
-  void operator []=(int pos, A a) {
-    value = a;
-  }
-
-  A get x => value;
-  void set x(A a) {
-    value = a;
-  }
-}
-
-// Subset of grammar being tested.
-//
-// expression:
-//       assignableExpression assignmentOperator expression
-//     | conditionalExpression cascadeSection*
-//     ;
-// expressionWithoutCascade:
-//       assignableExpression assignmentOperator expressionWithoutCascade
-//     | conditionalExpression
-//     ;
-// expressionList:
-//       expression (',' expression)*
-//     ;
-// assignableExpression:
-//       primary (arguments* assignableSelector)+
-//     | super assignableSelector
-//     | identifier
-//     ;
-// conditionalExpression:
-//     logicalOrExpression ('?' expressionWithoutCascade ':' expressionWithoutCascade)?
-//     ;
-// primary:
-//       thisExpression
-//     | super assignableSelector
-//     | functionExpression
-//     | literal
-//     | identifier
-//     | newExpression
-//     | constObjectExpression
-//     | '(' expression ')'
-//     ;
-// assignableSelector:
-//       '[' expression ']'
-//     | '.' identifier
-//     ;
-//
-// In words:
-//  An assignableExpression is either a variable or something ending in
-//  [expression] or .identifier.
-
-main() {
-  A a = new A(42);
-  A original = a;
-  A b = new A(87);
-  fa() => a;
-  Box box = new Box(a);
-  // Different expressions on the left-hand side of '..'.
-  //  conditionalExpression >> postfixExpression > primary selector*
-  Expect.equals(
-      a,
-      a
-        ..set(37)
-        ..get());
-  a.test(37);
-  Expect.equals(
-      a,
-      fa()
-        ..set(42)
-        ..get());
-  a.test(42);
-  Expect.equals(
-      a,
-      box.x
-        ..set(37)
-        ..get());
-  a.test(37);
-  // '..' binds to 'b + a', i.e., to the 'b' object, not to 'a'.
-  Expect.equals(
-      b,
-      b + a
-        ..test(124)
-        ..set(117)
-        ..get());
-  b.test(117);
-  a.test(37);
-
-  // expression :: conditionalExpression cascadeSection
-  // and conditionalExpression ends in expressionWithoutCascade.
-  // I.e., '..' binds to the entire condition expression, not to 'b'.
-  (a.value == 37) ? a : b
-    ..set(42);
-  a.test(42);
-
-  // This binds .. to 'a', not 'c=a', and performs assignment after reading
-  // c.get().
-  A c = new A(21);
-  c = a..set(c.get()); // FAILING.
-  Expect.equals(a, c);
-  Expect.equals(original, a);
-  a.test(21); // Fails as 42 if above is parsed as (c = a)..set(c.get()).
-
-  // Should be parsed as (box..x = (c = a))..x.test(21).
-  c = null;
-  box
-    ..x = c = a
-    ..x.test(21);
-  c.test(21);
-  // Other variants
-  c = null;
-  box
-    ..x = c = (a..test(21))
-    ..x.test(21);
-  c.test(21);
-
-  c = null;
-  box
-    ..x = (c = a..test(21))
-    ..x.test(21);
-  c.test(21);
-
-  // Should work the same:
-  (a..set(42))..test(42);
-  a
-    ..set(21)
-    ..test(21);
-
-  c = null;
-  Box originalBox = box;
-  // Should parse as:
-  // box = (box..x = (a.value == 21 ? b : c)..x.test(117));
-  box = box
-    ..x = a.value == 21 ? b : c
-    ..x.test(117);
-  Expect.equals(originalBox, box);
-  Expect.equals(box.value, b);
-
-  // New cascades are allowed inside an expressionWithoutCascade if properly
-  // delimited.
-  box
-    ..x = (a
-      ..set(42)
-      ..test(42))
-    ..x.test(42);
-}