Possible bug in sfYamlDumper

[Michael]

I've been seeing some weird results from some particular YAML like:

{ brand: Canon, shop: 3 }

I expect this to be, php array similar to:

array( 'brand' => 'Canon', 'shop' => 3 )

But in fact it turns into, php array similar to:

array( '{ brand' => 'Canon, shop: 3 }' )

On this online parser, I get the expected result:
http://yaml-online-parser.appspot.com/?yaml=%7B+brand%3A+Canon%2C+shop%3A+3+%7D&type=json

Is this a bug, or are { } constructs not allowed to be the 'root-
element' of the yaml?