Support non-const instance field initializers.

Support non-const instance field initializers.
Committed: https://code.google.com/p/dart/source/detail?r=11305

[kasperl, 2012-08-24 05:57:05]

Please add some tests for this new feature. At least we need to test (1) the
evaluation order -- also when it comes to the implicit super constructor call,
(2) side-effects when we have multiple assignments to the same field.

[ngeoffray, 2012-08-24 11:26:02]

Turns out the initial patch did not handle well initialization order and was
dropping some side-effect code.

The code is now fixed and I added a test. PTAL

[karlklose, 2012-08-24 11:46:22]

https://chromiumcodereview.appspot.com/10873033/diff/6001/lib/compiler/implem...
File lib/compiler/implementation/resolver.dart (right):

https://chromiumcodereview.appspot.com/10873033/diff/6001/lib/compiler/implem...
lib/compiler/implementation/resolver.dart:933: inInstanceContext =
(element.isInstanceMember() && !element.isField())
Please add a comment explaining why 'fields are not resolved in an instance
context'.

[kasperl, 2012-08-24 11:50:22]

LGTM, but I think you might be able to improve the readability of the tests.

https://chromiumcodereview.appspot.com/10873033/diff/6001/lib/compiler/implem...
File lib/compiler/implementation/elements/elements.dart (right):

https://chromiumcodereview.appspot.com/10873033/diff/6001/lib/compiler/implem...
lib/compiler/implementation/elements/elements.dart:1306: for (Element element in
classElement.localMembers.reverse()) {
Add a comment that explain why the order is important.

https://chromiumcodereview.appspot.com/10873033/diff/6001/tests/language/fiel...
File tests/language/field_initialization_order_test.dart (right):

https://chromiumcodereview.appspot.com/10873033/diff/6001/tests/language/fiel...
tests/language/field_initialization_order_test.dart:6: int counter = 0;
Counting is fun, but when you're dealing with order it might be better to use a
stringbuffer and add different markers. Maybe something like:

class Mark {
  static StringBuffer buffer;
  Mark(String op) {
    buffer.add("${op}.");
  }
}

String do(callback) {
  Mark.buffer = new StringBuffer();
  callback();
  return Mark.buffer.toString();
}

and then: 

class OneField {
  var a = new Mark("a");
  OneField();
  OneField.init() : a = new Mark("ai");
}

and then the tests:

main() {
  Expect.equals("a.", do(() => new OneField()));
  Expect.equals("a.ai.", do(() => new OneField.init()));
  ...
}

[ngeoffray, 2012-08-24 13:01:41]

Thank you Kasper and Karl.

https://chromiumcodereview.appspot.com/10873033/diff/6001/lib/compiler/implem...
File lib/compiler/implementation/elements/elements.dart (right):

https://chromiumcodereview.appspot.com/10873033/diff/6001/lib/compiler/implem...
lib/compiler/implementation/elements/elements.dart:1306: for (Element element in
classElement.localMembers.reverse()) {
On 2012/08/24 11:50:23, kasperl wrote:
> Add a comment that explain why the order is important.

Done.

https://chromiumcodereview.appspot.com/10873033/diff/6001/lib/compiler/implem...
File lib/compiler/implementation/resolver.dart (right):

https://chromiumcodereview.appspot.com/10873033/diff/6001/lib/compiler/implem...
lib/compiler/implementation/resolver.dart:933: inInstanceContext =
(element.isInstanceMember() && !element.isField())
On 2012/08/24 11:46:22, karlklose wrote:
> Please add a comment explaining why 'fields are not resolved in an instance
> context'.

Done.

https://chromiumcodereview.appspot.com/10873033/diff/6001/tests/language/fiel...
File tests/language/field_initialization_order_test.dart (right):

https://chromiumcodereview.appspot.com/10873033/diff/6001/tests/language/fiel...
tests/language/field_initialization_order_test.dart:6: int counter = 0;
On 2012/08/24 11:50:23, kasperl wrote:
> Counting is fun, but when you're dealing with order it might be better to use
a
> stringbuffer and add different markers. Maybe something like:
> 
> class Mark {
>   static StringBuffer buffer;
>   Mark(String op) {
>     buffer.add("${op}.");
>   }
> }
> 
> String do(callback) {
>   Mark.buffer = new StringBuffer();
>   callback();
>   return Mark.buffer.toString();
> }
> 
> and then: 
> 
> class OneField {
>   var a = new Mark("a");
>   OneField();
>   OneField.init() : a = new Mark("ai");
> }
> 
> and then the tests:
> 
> main() {
>   Expect.equals("a.", do(() => new OneField()));
>   Expect.equals("a.ai.", do(() => new OneField.init()));
>   ...
> }

Thanks for the suggestion. Done.