Allow trailing comma in parameter and argument lists.

Allow trailing comma in parameter and argument lists.

R=hausner@google.com

Committed: https://github.com/dart-lang/sdk/commit/6a4af257ccabf9d7874eed13857296cf3e4f3a62
Committed: https://github.com/dart-lang/sdk/commit/bee9ab8e7b00bb6d015ccbde0e06b57b3df9f024

[Lasse Reichstein Nielsen, 2016-06-22 08:03:19]

lrn@google.com changed reviewers:
+ hausner@google.com

[hausner, 2016-06-22 17:50:25]

Missing in the CL is the handling of the optional comma when "skipping"
expressions. (See relevant SkipXXX() functions.)

As I have expressed to floitsch, I wish we would update the spec first and
publish it, then make the changes in all platforms (including dart2js and
analyzer and other tools that people use). The spec change for this is not
checked in yet.

https://codereview.chromium.org/1991043004/diff/1/runtime/vm/parser.cc
File runtime/vm/parser.cc (right):

https://codereview.chromium.org/1991043004/diff/1/runtime/vm/parser.cc#newcod...
runtime/vm/parser.cc:2038: if (CurrentToken() == terminator) {
You are allowing an empty list of optional positional or named arguments with
this. In other words, you would allow a formal parameter list like this:

foo(a, [])

Which is probably not what you intended. On the other hand, I don't have a
authoritative spec.

https://codereview.chromium.org/1991043004/diff/1/runtime/vm/parser.cc#newcod...
runtime/vm/parser.cc:11130: if (LookaheadToken(1) != Token::kRPAREN) {
This special case for the empty argument list is no longer necessary with your
change. The new check you added will handle it correctly.

[Lasse Reichstein Nielsen, 2016-06-24 11:43:04]

Fixed empty optionals case.

I'm not sure there is a SkipFormalParameterList function. The
SkipFunctionLiteral function calls ParseFormalParameterList to skip the
parameters.

The SkipActualParameters seems to already accept a trailing comma.

https://codereview.chromium.org/1991043004/diff/1/runtime/vm/parser.cc
File runtime/vm/parser.cc (right):

https://codereview.chromium.org/1991043004/diff/1/runtime/vm/parser.cc#newcod...
runtime/vm/parser.cc:2038: if (CurrentToken() == terminator) {
Good point. 
Curiously, it's only an empty named block that gets accepted, something must be
catching the empty positional one elsewhere.

https://codereview.chromium.org/1991043004/diff/1/runtime/vm/parser.cc#newcod...
runtime/vm/parser.cc:11130: if (LookaheadToken(1) != Token::kRPAREN) {
True. It won't when I add code to prevent the empty optional parameter list,
though.

[hausner, 2016-06-25 04:08:31]

LGTM.

My concern about updating the other parsers (dart2js, analyzer, dartfmt)
remains.

[Lasse Reichstein Nielsen, 2016-07-04 10:51:11]

Description was changed from

==========
Allow trailing comma in parameter and argument lists.
==========

to

==========
Allow trailing comma in parameter and argument lists.

R=hausner@google.com

Committed:
https://github.com/dart-lang/sdk/commit/6a4af257ccabf9d7874eed13857296cf3e4f3a62
==========

[Lasse Reichstein Nielsen, 2016-07-04 10:51:13]

Committed patchset #3 (id:40001) manually as
6a4af257ccabf9d7874eed13857296cf3e4f3a62 (presubmit successful).

[Lasse Reichstein Nielsen, 2016-07-04 10:51:37]

The spec and test has been landed, so landing this as well.

[Lasse Reichstein Nielsen, 2016-07-04 10:51:38]

The spec and test has been landed, so landing this as well.

[Lasse Reichstein Nielsen, 2016-07-04 11:48:12]

Description was changed from

==========
Allow trailing comma in parameter and argument lists.

R=hausner@google.com

Committed:
https://github.com/dart-lang/sdk/commit/6a4af257ccabf9d7874eed13857296cf3e4f3a62
==========

to

==========
Allow trailing comma in parameter and argument lists.

R=hausner@google.com

Committed:
https://github.com/dart-lang/sdk/commit/6a4af257ccabf9d7874eed13857296cf3e4f3a62
Committed:
https://github.com/dart-lang/sdk/commit/bee9ab8e7b00bb6d015ccbde0e06b57b3df9f024
==========

[Lasse Reichstein Nielsen, 2016-07-04 11:48:13]

Committed patchset #4 (id:60001) manually as
bee9ab8e7b00bb6d015ccbde0e06b57b3df9f024 (presubmit successful).