Thank you for your reply,
I already read the thread you linked before posting.
I knew the existence of the __xmiID__ attribute, and I'm asking if there's something like __baseClass__ for access the base_Class identifier.
I'm sorry for being not much clear.
some attributes do not appear on the content assist.
For example if I have a UML!Class, the attribute __xmiID__ doesn't come out when I crtl+space on an object of type UML!Class, but if I use it, it works.
I'm asking if there's something analog for the base_Classifier attribute.
Just one general comment: from experience, when developing a model transformation, I would advice you to always have the corresponding metamodel(s) opened into an appropriate Model Browser as your "reference documentation/guide".
The content assist is just an extra-facility to gain time when writing down the actual transformation code.
It's kinda hard for UML2 profiles as you tend to think of them as extensions but they are actually metamodels, stereotypes being meta-classes.
If you use one single profile you can probably use it as the metamodel instead of UML2, as they include the UML2 metamodel.
Not sure if this will work for the ATL content assist though.