Work towards https://github.com/dart-lang/language/issues/2
The feature is well-specified at the issue, but I will also follow
up with a specification to check into the language repo.
This change implements the feature more-or-less from front to back
(because the back is very close to the front in this case :P; no
"backend" work in the VM, etc). Digit separators are made available
via a new experiment, `digit-separators`.
Care is taken to report a single error when an underscore appears in
an unexpected position (see new `separators_error_test.dart`).
Three test files are added:
* `separators_test.dart` is run with the experiment enabled, and has
no compile-time errors.
* `separators_error_test.dart` is run with the experiment enabled, and
has many compile-time errors.
* `separators_error_no_experiment_test.dart` is run with the
experiment _disabled_.
Change-Id: I7f1b1305d28b708b5ddf83f26188cd6e9ce3dd58
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/365181
Commit-Queue: Samuel Rawlins <srawlins@google.com>
Reviewed-by: Lasse Nielsen <lrn@google.com>
Reviewed-by: Kevin Moore <kevmoo@google.com>
Reviewed-by: Jens Johansen <jensj@google.com>
Sam Rawlins
5e8ee77772