the class list would be rendered by looking up the teacher's name. a rendering can be cached with a timestamp (it was valid as of this time) and then the most recent render can be stored. by setting a dirty flag whenever data changes, you can update dependencies when they are fetched and then memoize the results.
You still need consistent object identities to do that, which are then tantamount to mutability (they are equivalent with equivalent problems related to consistency, and similar solutions).
Comments
the class list would be rendered by looking up the teacher's name. a rendering can be cached with a timestamp (it was valid as of this time) and then the most recent render can be stored. by setting a dirty flag whenever data changes, you can update dependencies when they are fetched and then memoize the results.
You still need consistent object identities to do that, which are then tantamount to mutability (they are equivalent with equivalent problems related to consistency, and similar solutions).
can you elaborate?