| // 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. |
| |
| // @dart = 2.9 |
| |
| 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); |
| } |