Attribute Types in ViewPoint DSL Project

I could not find a way to define my own type and assign it to an attribute of another class. Could you please help on how to achieve it?
My current data file is as below. There is an error in the line where I say Z type X. I’m just defining my meta model the same way as I would do in xtext. What do you suggest ? {
Class Scenario {
Z type X
Class X
The way I see it now is to do the following. Is it the only way though?
Associations: Z contains [0,*] X

Indeed, based on what I know, you should use the associations.
It will also help you when defining the UI: I don’t think custom type attribute will be supported, while basic type attributes and associations are well supported.
Do you see any drawbacks in using associations instead of attribute definition in your case?

Hello Aurélien,
Thanks for the reply. I think associations are sufficient. In fact, based on the UML implications, all the attributes (non-primitives mostly) are better to be shown by association classes (if they have their own state within the domain). However, in terms of supporting different types of modellers who have have experienced XText, UML, SysMl, or other types of (meta-)modelling, it would be good to allow users use their own classes as custom types.