Implement new optional parameters syntax in the vm (issue 4290).

Implement new optional parameters syntax in the vm (issue 4290).
Provide --reject_named_argument_as_positional flag to ease transition to new
syntax (default is false).
Add tests.
Committed: https://code.google.com/p/dart/source/detail?r=12004

[hausner, 2012-09-07 00:23:29]

LGTM. Thank you for keeping the new and old code so nicely separated.

https://chromiumcodereview.appspot.com/10910119/diff/1/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://chromiumcodereview.appspot.com/10910119/diff/1/runtime/vm/object.cc#n...
runtime/vm/object.cc:3910: ASSERT(value >= 0);
I believe optional positional and optional named parameters are mutually
exclusive, correct? I could not see a place where we assert that that's the case
(other than the parser rejecting a function that has both.)

https://chromiumcodereview.appspot.com/10910119/diff/1/tests/language/positio...
File tests/language/positional_parameters_type_test.dart (right):

https://chromiumcodereview.appspot.com/10910119/diff/1/tests/language/positio...
tests/language/positional_parameters_type_test.dart:16: void
acceptFunNumOptBool(void funNumOptBool(num num, [bool b])) { };
Should this be num n instead of num num. Same comment for the next few
signatures.

[regis, 2012-09-07 01:11:33]

Thank you, Sir!

https://chromiumcodereview.appspot.com/10910119/diff/1/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://chromiumcodereview.appspot.com/10910119/diff/1/runtime/vm/object.cc#n...
runtime/vm/object.cc:3910: ASSERT(value >= 0);
On 2012/09/07 00:23:29, hausner wrote:
> I believe optional positional and optional named parameters are mutually
> exclusive, correct? I could not see a place where we assert that that's the
case
> (other than the parser rejecting a function that has both.)

Good point. I added an assert here and below.

https://chromiumcodereview.appspot.com/10910119/diff/1/tests/language/positio...
File tests/language/positional_parameters_type_test.dart (right):

https://chromiumcodereview.appspot.com/10910119/diff/1/tests/language/positio...
tests/language/positional_parameters_type_test.dart:16: void
acceptFunNumOptBool(void funNumOptBool(num num, [bool b])) { };
On 2012/09/07 00:23:29, hausner wrote:
> Should this be num n instead of num num. Same comment for the next few
> signatures.

Done here and in other tests.