UMLR — UML Super 2.1.2: section 18.3.2

In the semantics section the spec says

“When the extension is required, then the cardinality on the extension stereotype is “1.” The role names are provided using the following rule: The name of the role of the extended metaclass is: ‘base_’ extendedMetaclassName The name of the role of the extension stereotype is: ‘extension$_’ stereotypeName.”

I have two issues with this. This first is that in all example that follows – the extension role names don’t have a dollar in them and so are inconsistent with the spec.

Secondly, I think this should say that these are the default names if the modeller doesn’t provide any. In fact later on in the Presentation Options section of 18.3.8, the spec says:

“If the extension end is given a name, this name can be used in lieu of the stereotype name within the pair of guillemets when the stereotype is applied to a model element.”