A draft Erlang Enhancement Proposal (EEP) introduces application-scoped function visibility at the BEAM level. Two new module attributes are proposed: -app/1 to declare an application domain, and -app_export/1 to mark functions as internal to that domain. Functions listed in -app_export/1 remain exported but the BEAM runtime restricts calls to them from modules in the same app domain only — cross-domain calls raise a badappcall error. The goal is to make internal APIs explicit and enforceable without new syntax changes, complementing existing EEP 5 and EEP 67 with runtime rather than static enforcement. The author seeks community feedback on attribute naming, derivation strategy, runtime enforcement desirability, error shape, and VM/JIT performance impact.
