More about this can be found in the literature on using capabilities to provide/implement effect systems. For example: - "Capabilities: Effects for Free": http

More about this can be found in the literature on using capabilities to provide/implement effect systems. For example: - "Capabilities: Effects for Free": https://www.cs.cmu.edu/~aldrich/papers/effects-icfem2018.pdf https://www.cs.cmu.edu/~aldrich/papers/effects-icfem2018.pdf - "Effects as Capabilities: Effect Handlers and Lightweight Effect Polymorphism" https://dl.acm.org/doi/pdf/10.1145/3428194 https://dl.acm.org/doi/pdf/10.1145/3428194 I think this is a quite effective approach and I hope it is used more. In some sense it's just good coding style, which lets you do effect-system-style reasoning in any language.