It sounds it is a problem but I feel it can be solved with engineering and mathematics. Not saying it would be easy though.
Couldn't you separate the storage of the refcounts from the objects and use a map to get at them?
As for the identities between types being different.
To create an subinterpreter that can marshall between subinterpreters without copying the data structures requires a different data structure that is safe to use from any interpreter. We need to decouple the book keeping data structures from the underlying data.
We can regenerate book keeping data structures during a .send or .receive
Maintaining identity equivalence is an interesting problem. I think it's a more fundamental problem that probably has mathematical solutions.
If we think of objects as being a vector in mathematical space. We have pointers between vectors in this memory space.
For a data structure to be position independent. We need some way of intending references to be global. But we don't want to introduce a layer of indirection on the reference of object relationships. That would be slower. Could use an atomic counter to ensure that identifiers are globally unique.
Don't want to serialize the access to global types.
It sounds to me it is a many-to-many to many-to-many problem. Which even databases don't solve very well.
Couldn't you separate the storage of the refcounts from the objects and use a map to get at them?
As for the identities between types being different.
To create an subinterpreter that can marshall between subinterpreters without copying the data structures requires a different data structure that is safe to use from any interpreter. We need to decouple the book keeping data structures from the underlying data.
We can regenerate book keeping data structures during a .send or .receive
Maintaining identity equivalence is an interesting problem. I think it's a more fundamental problem that probably has mathematical solutions.
If we think of objects as being a vector in mathematical space. We have pointers between vectors in this memory space.
For a data structure to be position independent. We need some way of intending references to be global. But we don't want to introduce a layer of indirection on the reference of object relationships. That would be slower. Could use an atomic counter to ensure that identifiers are globally unique.
Don't want to serialize the access to global types.
It sounds to me it is a many-to-many to many-to-many problem. Which even databases don't solve very well.