Kallen Tu
8bfb683892
This CL enables the primary constructors feature by default in Dart 3.13.
The primary constructors feature is a brevity feature. There are no new semantics, but it allows us to express declarations in a less verbose way.
This feature allows one constructor and a set of instance variables to be specified in the header of a declaration.
Currently a declaration with a constructor and some fields is written as:
```dart
// Current syntax.
class Point {
int x;
int y;
Point(this.x, this.y);
}
```
With a primary constructor, we would write the above as:
```
class Point(var int x, var int y);
```
If a primary constructor needs an initializer list or a body, they can be
specified inside the class using the `this` body syntax:
```dart
class Point(var int x, var int y) {
this : assert(x >= 0) {
print('Point created at $x, $y');
}
}
```
As part of this feature, you can also use the `new` and `factory` keywords to
declare constructors in the class body without repeating the class name:
```dart
class Point {
int x, y;
// Equivalent to Point(this.x, this.y)
new(this.x, this.y);
// Equivalent to Point.origin()
new origin() : x = 0, y = 0;
// Equivalent to factory Point.clone(Point other)
factory clone(Point other) => Point(other.x, other.y);
}
```
To learn more about the feature, check out the feature specification located here: https://github.com/dart-lang/language/blob/main/accepted/future-releases/primary-constructors/feature-specification.md
Tested: Has existing language, CFE, analyzer, analysis server tests.
Bug: https://github.com/dart-lang/sdk/issues/61524
Change-Id: I296f2fcd918b87bf2a1dd00256340759866c2423
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/489241
Reviewed-by: Bob Nystrom <rnystrom@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Reviewed-by: Nicholas Shahan <nshahan@google.com>
Reviewed-by: Michael Thomsen <mit@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Kallen Tu <kallentu@google.com>
Reviewed-by: Ben Konyi <bkonyi@google.com>
84 lines
2.4 KiB
Dart
84 lines
2.4 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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import 'package:compiler/compiler_api.dart' as api;
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import 'package:expect/async_helper.dart';
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import 'package:expect/expect.dart';
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import 'package:compiler/src/util/memory_compiler.dart';
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// Use strict does not allow parameters or locals named "arguments" or "eval".
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const MEMORY_SOURCE_FILES = const {
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'main.dart': '''
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class A {
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final arguments;
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final eval;
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A(this.arguments, this.eval);
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foo(x, y) => this.arguments + this.eval;
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}
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class B {
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foo(arguments, eval) => arguments + eval;
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}
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class C {
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foo(x, y) {
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var arguments, eval;
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arguments = x + y;
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eval = x - y;
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if (arguments < eval) return arguments;
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return eval;
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}
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}
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main() {
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var list = [];
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for (int i = 0; i < 1000; i++) {
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list.add(new A(i, i + 1));
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list.add(new B());
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list.add(new C());
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}
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for (int i = 0; i < list.length; i++) {
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print(list[i].foo(i, i + 1));
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}
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}''',
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};
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main() {
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runTest() async {
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OutputCollector collector = OutputCollector();
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await runCompiler(
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memorySourceFiles: MEMORY_SOURCE_FILES,
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outputProvider: collector,
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);
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String jsOutput = collector.getOutput('', api.OutputType.js)!;
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// Skip comments.
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List<String> lines = jsOutput.split("\n");
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// Filter out any lines unrelated to the code above where dart2js today
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// produces the text "eval" or "arguments"
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// Currently this includes comments, and a few lines in the body of
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// Closure.cspForwardCall and Closure.cspForwardInterceptedCall.
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List<RegExp> filters = [
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RegExp(r' *//'), // skip comments
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RegExp(r'"Intercepted function with no arguments."'),
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RegExp(r'f.apply\(receiverOf\(this\), arguments\)'),
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RegExp(r'Array.prototype.push.apply\(a, arguments\)'),
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];
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String filtered = lines
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.where((String line) => !filters.any((regexp) => regexp.hasMatch(line)))
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.join("\n");
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RegExp re = RegExp(r'[^\w$](arguments|eval)[^\w$]');
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Expect.isFalse(re.hasMatch(filtered));
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}
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asyncTest(() async {
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print('--test from kernel------------------------------------------------');
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await runTest();
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});
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}
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