Don't use regular expressions in Loader.

Don't use regular expressions in Loader.

This is based on https://codereview.chromium.org/1325053002. It also
avoids redundant parsing where possible.

Closes #12

R=rnystrom@google.com

Committed: https://github.com/dart-lang/yaml/commit/445e54eeed61e281968a33f10e6781914c533be5

[Bob Nystrom, 2015-09-02 23:13:14]

https://codereview.chromium.org/1329763002/diff/1/lib/src/scanner.dart
File lib/src/scanner.dart (right):

https://codereview.chromium.org/1329763002/diff/1/lib/src/scanner.dart#newcod...
lib/src/scanner.dart:295: : _scanner = new SpanScanner(source, sourceUrl:
sourceUrl);
Do you need to merge in that previous change?

https://codereview.chromium.org/1329763002/diff/1/pubspec.yaml
File pubspec.yaml (right):

https://codereview.chromium.org/1329763002/diff/1/pubspec.yaml#newcode14
pubspec.yaml:14: sdk: '>=1.12.0 <2.0.0'
I worry this is too restrictive for consumers of the package. Maybe hold off on
null-aware operators until 1.13 and more people have had time to upgrade to
1.12?

[nweiz, 2015-09-02 23:37:56]

Code review changes

[nweiz, 2015-09-02 23:38:00]

https://codereview.chromium.org/1329763002/diff/1/lib/src/scanner.dart
File lib/src/scanner.dart (right):

https://codereview.chromium.org/1329763002/diff/1/lib/src/scanner.dart#newcod...
lib/src/scanner.dart:295: : _scanner = new SpanScanner(source, sourceUrl:
sourceUrl);
On 2015/09/02 23:13:14, Bob Nystrom wrote:
> Do you need to merge in that previous change?

Oops!

https://codereview.chromium.org/1329763002/diff/1/pubspec.yaml
File pubspec.yaml (right):

https://codereview.chromium.org/1329763002/diff/1/pubspec.yaml#newcode14
pubspec.yaml:14: sdk: '>=1.12.0 <2.0.0'
On 2015/09/02 23:13:14, Bob Nystrom wrote:
> I worry this is too restrictive for consumers of the package. Maybe hold off
on
> null-aware operators until 1.13 and more people have had time to upgrade to
> 1.12?

I agree when making API changes, but we aren't doing that here, nor do we plan
to in the near future. This isn't likely to cause version lock, and I don't feel
bad about telling users to use the latest SDK for the best performance.

[Bob Nystrom, 2015-09-03 00:49:57]

lgtm

[nweiz, 2015-09-03 01:02:07]

Committed patchset #2 (id:20001) manually as
445e54eeed61e281968a33f10e6781914c533be5 (presubmit successful).