Developing your own 'language' with the help of GOP is only needed if it is a very specific language you need. Project Management can probably be implemented on top of BPM. Since the latter is much simpler, I would look at that first
I think there is possibility to map process node types to project node types. For example:
task in process -> task in project
state -> milestone
SubProcess -> SubProject
May be another meaning for jPDL nodes should be sufficient.
Another issue is how to handle changes in the project plan.
Project plan is
A->B->C (token is on node B)
would change to
and when token should be. and different questions.
I will try to specify different tests for such as changes in the project plan.
Main difference is, that project has mainly only one instance.
If the project is done several times could it be established as process?
Could project plan grow to the process graph?
I do not understand your A->B... stuff. Maybe if you put it in [ c o d e ] tags (without spaces) it will be readable, use preview to check that).
Besides that, I would hope the way you carry out projects is fairly the same, not reinvent new was to do it each time ;-)