Use identical or optional for keywords.

Use identical or optional for keywords.

R=johnniwinther@google.com

Committed: https://github.com/dart-lang/sdk/commit/d1a12f985227d427f245282f343af658a266ed21

[ahe, 2017-03-17 11:50:08]

ahe@google.com changed reviewers:
+ johnniwinther@google.com

[Johnni Winther, 2017-03-17 12:03:52]

lgtm

https://codereview.chromium.org/2759643002/diff/1/pkg/front_end/lib/src/fasta...
File pkg/front_end/lib/src/fasta/parser/parser.dart (right):

https://codereview.chromium.org/2759643002/diff/1/pkg/front_end/lib/src/fasta...
pkg/front_end/lib/src/fasta/parser/parser.dart:1: // Copyright (c) 2012, the
Dart project authors.  Please see the AUTHORS file
Add a comment about when and why we use `identical`.

https://codereview.chromium.org/2759643002/diff/1/pkg/front_end/lib/src/fasta...
pkg/front_end/lib/src/fasta/parser/parser.dart:2722: } else if (kind ==
OPEN_SQUARE_BRACKET_TOKEN || optional('[]', token)) {
Why use `optional`? Is it faster? (It doesn't read as well as using
`identical`).

[ahe, 2017-03-17 13:48:27]

Thank you, Johnni!

https://codereview.chromium.org/2759643002/diff/1/pkg/front_end/lib/src/fasta...
File pkg/front_end/lib/src/fasta/parser/parser.dart (right):

https://codereview.chromium.org/2759643002/diff/1/pkg/front_end/lib/src/fasta...
pkg/front_end/lib/src/fasta/parser/parser.dart:1: // Copyright (c) 2012, the
Dart project authors.  Please see the AUTHORS file
On 2017/03/17 12:03:52, Johnni Winther wrote:
> Add a comment about when and why we use `identical`.

I'll update the documentation comment of the Parser class in a follow-up CL.
I've noticed a few things that could use an overhaul.

https://codereview.chromium.org/2759643002/diff/1/pkg/front_end/lib/src/fasta...
pkg/front_end/lib/src/fasta/parser/parser.dart:2722: } else if (kind ==
OPEN_SQUARE_BRACKET_TOKEN || optional('[]', token)) {
On 2017/03/17 12:03:52, Johnni Winther wrote:
> Why use `optional`? Is it faster? (It doesn't read as well as using
> `identical`).

For consistency, I prefer to use "optional" unless there's a lot of tests. The
implementation of "optional" is exactly what you'd expect after converting this
to use identical.

If you have any suggestions for how to make uses of optional easier to read, I
welcome suggestions.

[ahe, 2017-03-17 13:56:09]

Description was changed from

==========
Use identical or optional for keywords.
==========

to

==========
Use identical or optional for keywords.

R=johnniwinther@google.com

Committed:
https://github.com/dart-lang/sdk/commit/d1a12f985227d427f245282f343af658a266ed21
==========

[ahe, 2017-03-17 13:56:10]

Committed patchset #1 (id:1) manually as
d1a12f985227d427f245282f343af658a266ed21 (presubmit successful).