Make YamlException inherit from SpanFormatException.

Make YamlException inherit from SpanFormatException.

R=rnystrom@google.com

Committed: https://code.google.com/p/dart/source/detail?r=37618

[Bob Nystrom, 2014-06-19 23:31:04]

https://codereview.chromium.org/342943006/diff/1/pkg/yaml/lib/src/yaml_except...
File pkg/yaml/lib/src/yaml_exception.dart (right):

https://codereview.chromium.org/342943006/diff/1/pkg/yaml/lib/src/yaml_except...
pkg/yaml/lib/src/yaml_exception.dart:10: class YamlException extends
SpanFormatException {
I'm generally hesitant to inherit across package boundaries. Inheritance is just
about the tightest coupling possible, so it can set you up for pain.

Would it work to have YamlException contain a SpanFormatException?

[nweiz, 2014-06-19 23:47:52]

https://codereview.chromium.org/342943006/diff/1/pkg/yaml/lib/src/yaml_except...
File pkg/yaml/lib/src/yaml_exception.dart (right):

https://codereview.chromium.org/342943006/diff/1/pkg/yaml/lib/src/yaml_except...
pkg/yaml/lib/src/yaml_exception.dart:10: class YamlException extends
SpanFormatException {
On 2014/06/19 23:31:04, Bob Nystrom wrote:
> I'm generally hesitant to inherit across package boundaries. Inheritance is
just
> about the tightest coupling possible, so it can set you up for pain.
> 
> Would it work to have YamlException contain a SpanFormatException?

The point of SpanException and SpanFormatException is for other packages to
inherit them. For example, it's important that applications (such as Pub) can do

    if (error is SpanException) {
      print(error.toString(useColor: true))
    }

in their top-level error handling.

[Bob Nystrom, 2014-06-20 17:22:54]

OK, LGTM.

[nweiz, 2014-06-23 21:07:06]

Committed patchset #1 manually as r37618 (presubmit successful).