Change Duration to take proper named optional parameters.

Change Duration to take proper named optional parameters.


R=bak@google.com,lrn@google.com
BUG=

Committed: https://code.google.com/p/dart/source/detail?r=12314

[bakster, 2012-09-13 09:00:01]

LGTM,
  Lars

https://chromiumcodereview.appspot.com/10905255/diff/1/lib/core/duration.dart
File lib/core/duration.dart (right):

https://chromiumcodereview.appspot.com/10905255/diff/1/lib/core/duration.dart...
lib/core/duration.dart:20: int milliseconds});
It would be great to have the default values listed in this interface.

https://chromiumcodereview.appspot.com/10905255/diff/1/pkg/unittest/test_case...
File pkg/unittest/test_case.dart (right):

https://chromiumcodereview.appspot.com/10905255/diff/1/pkg/unittest/test_case...
pkg/unittest/test_case.dart:89: runningTime = new Duration(milliseconds: 0);
How about introducing a static or a named constructor:
   Duration.empty
instead of using:
   new Duration() and 
   new new Duration(milliseconds: 0)

[kasperl, 2012-09-13 09:04:46]

https://chromiumcodereview.appspot.com/10905255/diff/1/pkg/unittest/test_case...
File pkg/unittest/test_case.dart (right):

https://chromiumcodereview.appspot.com/10905255/diff/1/pkg/unittest/test_case...
pkg/unittest/test_case.dart:89: runningTime = new Duration(milliseconds: 0);
On 2012/09/13 09:00:01, bakster wrote:
> How about introducing a static or a named constructor:
>    Duration.empty
> instead of using:
>    new Duration() and 
>    new new Duration(milliseconds: 0)

That's fine but that extra constructor will not make it impossible to use new
Duration() or new Duration(milliseconds: 0), right? Unless we start adding some
kind of weird constraint that you have to pass at least one named argument
somehow.

[Lasse Reichstein Nielsen, 2012-09-13 09:30:46]

lgtm

https://chromiumcodereview.appspot.com/10905255/diff/1/pkg/unittest/test_case...
File pkg/unittest/test_case.dart (right):

https://chromiumcodereview.appspot.com/10905255/diff/1/pkg/unittest/test_case...
pkg/unittest/test_case.dart:89: runningTime = new Duration(milliseconds: 0);
Not prevent it, but perhaps it will preempt it by being the better alternative.
E.g.:
 Duration.zero() : this(milliseconds: 0); 
This is more readable, so people will hopefully prefer to use it.

https://chromiumcodereview.appspot.com/10905255/diff/1/runtime/lib/date_patch...
File runtime/lib/date_patch.dart (right):

https://chromiumcodereview.appspot.com/10905255/diff/1/runtime/lib/date_patch...
runtime/lib/date_patch.dart:34: if (isUtc) return new Duration();
If not introducing the zero-duration, be consistent and use milliseconds: 0
here.

[kasperl, 2012-09-13 09:45:49]

https://chromiumcodereview.appspot.com/10905255/diff/1/runtime/lib/date_patch...
File runtime/lib/date_patch.dart (right):

https://chromiumcodereview.appspot.com/10905255/diff/1/runtime/lib/date_patch...
runtime/lib/date_patch.dart:34: if (isUtc) return new Duration();
On 2012/09/13 09:30:46, Lasse Reichstein Nielsen wrote:
> If not introducing the zero-duration, be consistent and use milliseconds: 0
> here.

I'm reluctant to start refactoring these things while I'm still trying to get
through all the code and "upgrade" it to the new optional parameter syntax and
semantics.

This is just the first of a ton of changes to the core libraries that we need to
do to enable the new semantics of positional optional parameters.