IN C_DEFINED_OBJECT is default_value as property, which has as explanation that it is mostly used by leafnodes, so, these are the primitive_objects. In the grammar, I cannot find a constraint to use for default_value. I think this is an error, or it is not very well explained how to handle this.
I looked further in the previous version of AOM/ADL, which also has a default_value. I looked at the code from Rong, he always has, on the primitives, a constructor which includes a default_value.
The first constructor has a default_value, but the second hasn't.
But when you look here:
Line 3137 and 3197, both are lines where the constructor of C_DATE is called, Both call the constructor without default_value.
This means, that default_value was in the specs but it was never used in the Java-libs, also not used in all software based on java-libs.
I don't think this is a good situation.
But what to do?
When I look at the current grammar
c_date: ( DATE_CONSTRAINT_PATTERN | date_value | date_list_value | date_interval_value | date_interval_list_value ) assumed_date_value? ;
assumed_date_value: ';' date_value ;
I see the pattern, and in a exclusive or, all the other possible constraints, which are mostly lists. And it ends with assumed_date_value.
So, again, no default_value.
I find this very confusing.
At the moment the grammar doesn't support default values, and noone uses them in any archetypes, either ADL 1.4 or 2. We probably should put it off until a next release. I'll try and address the documentation, which I agree is currently confusing on this.
It is confusing, indeed. Better remove it for the time being, is my opinion, it doesn't look good