that's great so far. One of the features of EVL is "Out-of-the-box integration with the EMF validation framework and GMF"..Since I'mn using an combined EMF/GMF Editor and the meta model constraint is only part of the EMF Editor (for this classes, there are no eugenia annotations in the emf file, but I'm still using Eugenia to generate both editors). I'm wondering if EVL also works in the EMF Editor or is just applicable for the gmf editor??
These errors come from EMF itself as your model doesn't seem to be conforming to the cardinalities specified in its metamodel (e.g. a VariationElement is required to have a Remove, a ConcreteProperty etc as the minimum cardinality of its respective references is 1). To make these errors go away I'd suggest that you set the cardinalities of these references to 0..1 instead.
The class looks correct. Could you please double-check that the namespaceURI in your constraintBinding extension matches that of your root Ecore package? If it does, please send me a copy of your project at email@example.com and I'll investigate.
The namespaceURI should be /org.model.variability/model/pld.ecore (the same as the uri of your package). You can use the browse button next to the markerType field in plugin.xml to find the correct marker type.
Your plugin.xml looks fine but unfortunately I'm not able to run the editor as I'm missing a couple of plugins (de.itemis.xtext.utils.gmf, de.itemis.xtext.utils.jface). Could you please try with a clean GMF editor to see whether it's the interplay with Xtext that's causing this problem?
the interplay with xtext wasn't causing any problems. I had a small misstake in my check sentence, which I didn't noticed all the time. Now it's working as you can see:
But I observed an unexpected (for me) behaviour.
It's necessary to validate from the top of the tree in order to get a correct validation message. After this it doesn't matter in which part of the tree you click on validate, it's working then like expected.
But if you didn't start validating from the top of the tree, you always get a "Validation compledted succesfully" message: