Support named constants, or imports? about cedar HOT 1 OPEN

Thanks for submitting this request! I've tagged this requires-RFC because it would be a substantial change to the language which we wouldn't make without careful planning.

I think you're actually asking for a restricted version of the macro mechanism proposed in cedar-policy/rfcs#61. We're not actively considering that proposal at the moment, but we haven't rejected it completely either. Definitely restart discussion there if that proposal sounds useful. You could also write a fresh RFC proposing a more limited version of macros that work for you, potential avoiding some of the thornier issues identified in general macros.

Depending on your exact use case, we might be able to suggest a nicer alternative. In your example, the uuid appears in the principal constraint. If it only occurs there (or in the resource constraint), then you may be able to use policy templates as a safe alternative to find-and-replace. E.g., given a template permit(principal in ?principal, ...); the Cedar sdk provides a method to construct a template-linked-policy by replacing ?principal with a particular entity uid. If templates don't quite meet your needs, you could restart discussion on some extension to templates we previously considered but decided not to accept: templates groups, and template slots in policy conditions.

from cedar.