Add a friendly error message for using a tab as indentation.

Add a friendly error message for using a tab as indentation.

BUG=4813
Committed: https://code.google.com/p/dart/source/detail?r=11644

[Bob Nystrom, 2012-08-30 16:43:51]

Couple of suggestions. After those, LGTM.

https://chromiumcodereview.appspot.com/10886055/diff/1/utils/pub/yaml/parser....
File utils/pub/yaml/parser.dart (right):

https://chromiumcodereview.appspot.com/10886055/diff/1/utils/pub/yaml/parser....
utils/pub/yaml/parser.dart:712: annotateError("\\t is not allowed as indentation
in YAML",
I would use "tab characters" instead of the escape sequence here.

https://chromiumcodereview.appspot.com/10886055/diff/1/utils/pub/yaml/parser....
utils/pub/yaml/parser.dart:723: annotateError("\\t is not allowed as indentation
in YAML", () {
Ditto.

https://chromiumcodereview.appspot.com/10886055/diff/1/utils/tests/pub/yaml_t...
File utils/tests/pub/yaml_test.dart (right):

https://chromiumcodereview.appspot.com/10886055/diff/1/utils/tests/pub/yaml_t...
utils/tests/pub/yaml_test.dart:75: Expect.throws(() => loadYaml('foo:\n\tbar'),
expect(() => loadYaml('foo:\n\tbar'),
    throwsA(contains('\\t is not allowed as indentation'));

https://chromiumcodereview.appspot.com/10886055/diff/1/utils/tests/pub/yaml_t...
utils/tests/pub/yaml_test.dart:84: (e) => !e.toString().contains('\\t is not
allowed as indentation'));
Ditto.

We're trying to phase out all uses of Expect and eventually eliminate it from
corelib.

[nweiz, 2012-08-30 19:19:02]

https://chromiumcodereview.appspot.com/10886055/diff/1/utils/pub/yaml/parser....
File utils/pub/yaml/parser.dart (right):

https://chromiumcodereview.appspot.com/10886055/diff/1/utils/pub/yaml/parser....
utils/pub/yaml/parser.dart:712: annotateError("\\t is not allowed as indentation
in YAML",
On 2012/08/30 16:43:51, Bob Nystrom wrote:
> I would use "tab characters" instead of the escape sequence here.

Done.

https://chromiumcodereview.appspot.com/10886055/diff/1/utils/pub/yaml/parser....
utils/pub/yaml/parser.dart:723: annotateError("\\t is not allowed as indentation
in YAML", () {
On 2012/08/30 16:43:51, Bob Nystrom wrote:
> Ditto.

Done.

https://chromiumcodereview.appspot.com/10886055/diff/1/utils/tests/pub/yaml_t...
File utils/tests/pub/yaml_test.dart (right):

https://chromiumcodereview.appspot.com/10886055/diff/1/utils/tests/pub/yaml_t...
utils/tests/pub/yaml_test.dart:75: Expect.throws(() => loadYaml('foo:\n\tbar'),
On 2012/08/30 16:43:51, Bob Nystrom wrote:
> expect(() => loadYaml('foo:\n\tbar'),
>     throwsA(contains('\\t is not allowed as indentation'));

Done, although just "contains()" doesn't work here, since we're matching against
an exception rather than a string.

https://chromiumcodereview.appspot.com/10886055/diff/1/utils/tests/pub/yaml_t...
utils/tests/pub/yaml_test.dart:84: (e) => !e.toString().contains('\\t is not
allowed as indentation'));
On 2012/08/30 16:43:51, Bob Nystrom wrote:
> Ditto.
> 
> We're trying to phase out all uses of Expect and eventually eliminate it from
> corelib.

Done.