Scanner/parser support for DEP 9 (null-aware operators).

Scanner/parser support for DEP 9 (null-aware operators).

This adds scanner and parser support for the operators '?.', '??', and
'??='.

Support is not yet enabled--it is only turned on during the unit tests
for the new tokens and AST's.

R=brianwilkerson@google.com

Committed: https://code.google.com/p/dart/source/detail?r=44770

[Paul Berry, 2015-03-27 22:07:58]

paulberry@google.com changed reviewers:
+ brianwilkerson@google.com

[Brian Wilkerson, 2015-03-27 22:56:37]

LGTM!

https://codereview.chromium.org/1043583002/diff/1/pkg/analyzer/test/generated...
File pkg/analyzer/test/generated/parser_test.dart (right):

https://codereview.chromium.org/1043583002/diff/1/pkg/analyzer/test/generated...
pkg/analyzer/test/generated/parser_test.dart:4856:
expect(propertyAccess.operator.type, TokenType.PERIOD);
I generally prefer to leave in the explicit tests for null values
("expect(propertyAccess.operator, isNotNull);") because I find it easier to
debug problems, but it's your call (and might not be as true with unittest as it
was with JUnit).

[Paul Berry, 2015-03-28 02:25:09]

https://codereview.chromium.org/1043583002/diff/1/pkg/analyzer/test/generated...
File pkg/analyzer/test/generated/parser_test.dart (right):

https://codereview.chromium.org/1043583002/diff/1/pkg/analyzer/test/generated...
pkg/analyzer/test/generated/parser_test.dart:4856:
expect(propertyAccess.operator.type, TokenType.PERIOD);
On 2015/03/27 22:56:37, Brian Wilkerson wrote:
> I generally prefer to leave in the explicit tests for null values
> ("expect(propertyAccess.operator, isNotNull);") because I find it easier to
> debug problems, but it's your call (and might not be as true with unittest as
it
> was with JUnit).

Done.

[Paul Berry, 2015-03-28 02:25:46]

Committed patchset #1 (id:1) manually as 44770 (presubmit successful).