notes about MOF and UML

I just read an old post(MOF 4 layers) about the mapping between UML and MOF. However, I'd like to post my idea about UML mapping to MOF 4 layers.

As a reminder, MOF 4 layers structure from that post is pasted here.
* Level M0: User Object Layer (Instances)
* Level M1: Model (Domain Specific Language)
* Level M2: Meta-Model (Schema description Language)
* Level M3: Meta-Meta-Model (The Schema of the Schema)
And here is an architecture image about MOF:



The basic thinking is think of each layer as instantiation of the layer above. So I think it works this way:

* Layer M0: specific instances of model diagrams, e.g. a book named "UML distilled"

* Layer M1: UML model diagrams we drawed when we do modeling, e.g. e-bookshop class diagrams and use case diagrams. Actually it is the equivalent of C source file.

* Layer M2: UML meta model, e.g. model element specified in UML, class, interface, association, generalization,property,method, component and so on. It is the equivalent of C syntax.

* Layer M3: UML meta meta model, maybe its basic model elements is entity and relationship. It is the equivalent of syntax definition specification like EBNF.