ahe@google.com
10f43e1304
Review URL: https://chromiumcodereview.appspot.com//10829416 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@10943 260f80e4-7a28-3924-810f-c04153c831b5
138 lines
3.7 KiB
Dart
138 lines
3.7 KiB
Dart
// Copyright (c) 2011, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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class A {
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int value;
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A(this.value);
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void set(int value) { this.value = value; }
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int get() => value;
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int operator[](int index) => value + index;
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void operator[]=(int index, int newValue) { value += -index + newValue; }
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void test(int expected) {
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Expect.equals(expected, value);
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}
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Function limp(int n) {
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if (n == 0) return set;
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return () => limp(n - 1);
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}
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A get self => this;
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A operator+(A other) {
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this.value += other.value;
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return this;
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}
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}
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class Box {
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A value;
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Box(this.value);
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A operator[](int pos) => value;
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void operator[]=(int pos, A a) { value = a; }
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A get x => value;
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void set x(A a) { value = a; }
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}
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// Subset of grammar being tested.
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//
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// expression:
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// assignableExpression assignmentOperator expression
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// | conditionalExpression cascadeSection*
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// ;
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// expressionWithoutCascade:
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// assignableExpression assignmentOperator expressionWithoutCascade
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// | conditionalExpression
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// ;
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// expressionList:
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// expression (',' expression)*
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// ;
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// assignableExpression:
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// primary (arguments* assignableSelector)+
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// | super assignableSelector
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// | identifier
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// ;
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// conditionalExpression:
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// logicalOrExpression ('?' expressionWithoutCascade ':' expressionWithoutCascade)?
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// ;
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// primary:
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// thisExpression
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// | super assignableSelector
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// | functionExpression
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// | literal
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// | identifier
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// | newExpression
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// | constObjectExpression
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// | '(' expression ')'
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// ;
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// assignableSelector:
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// '[' expression ']'
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// | '.' identifier
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// ;
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//
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// In words:
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// An assignableExpression is either a variable or something ending in
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// [expression] or .identifier.
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main() {
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A a = new A(42);
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A original = a;
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A b = new A(87);
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fa() => a;
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Box box = new Box(a);
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// Different expressions on the left-hand side of '..'.
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// conditionalExpression >> postfixExpression > primary selector*
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Expect.equals(a, a..set(37)..get());
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a.test(37);
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Expect.equals(a, fa()..set(42)..get());
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a.test(42);
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Expect.equals(a, box.x..set(37)..get());
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a.test(37);
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// '..' binds to 'b + a', i.e., to the 'b' object, not to 'a'.
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Expect.equals(b, b + a..test(124)..set(117)..get());
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b.test(117);
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a.test(37);
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// expression :: conditionalExpression cascadeSection
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// and conditionalExpression ends in expressionWithoutCascade.
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// I.e., '..' binds to the entire condition expression, not to 'b'.
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(a.value == 37) ? a : b..set(42);
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a.test(42);
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// This binds .. to 'a', not 'c=a', and performs assignment after reading
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// c.get().
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A c = new A(21);
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c = a..set(c.get()); // FAILING.
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Expect.equals(a, c);
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Expect.equals(original, a);
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a.test(21); // Fails as 42 if above is parsed as (c = a)..set(c.get()).
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// Should be parsed as (box..x = (c = a))..x.test(21).
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c = null;
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box..x = c = a..x.test(21);
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c.test(21);
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// Other variants
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c = null;
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box..x = c = (a..test(21))..x.test(21);
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c.test(21);
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c = null;
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box..x = (c = a..test(21))..x.test(21);
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c.test(21);
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// Should work the same:
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(a..set(42))..test(42);
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a..set(21)..test(21);
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c = null;
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Box originalBox = box;
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// Should parse as:
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// box = (box..x = (a.value == 21 ? b : c)..x.test(117));
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box = box..x = a.value == 21 ? b : c..x.test(117);
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Expect.equals(originalBox, box);
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Expect.equals(box.value, b);
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// New cascades are allowed inside an expressionWithoutCascade if properly
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// delimited.
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box..x = (a..set(42)..test(42))..x.test(42);
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}
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