The new YAML data representation is great.
But I think the https://plantuml.com/yaml page should note that only a subset of YAML is supported.
The unsupported features I've noticed are:
- Node anchors and references give an error
- Flow style (embedded JSON) interprets as a string
- Literal(|)/Folded(>) blocks give an error
As a result, some of the examples in http://en.wikipedia.org/wiki/YAML don't work in PlantUML.
In fact the PlantUML implementation is closer to StrictYAML which also doesn't like some of these YAML features (e.g. see https://hitchdev.com/strictyaml/why/node-anchors-and-references-removed/) - which might be a better specification to aim for.
Another issue is that they still give the error message "Your data does not sound like JSON data" - should that read YAML data?