A C++ reader brings habits from RAII, overload sets, templates, references, optional values, exceptions, and object hierarchies. That helps with ownership stories, value categories, and compile-time abstractions, but the Musi page asks a narrower question: what contract should this module and package boundaries example make visible?
#include "option.hpp"
auto default_gate() -> Option<int>;let option := import "@std/option";
export let defaultGate : option.Option[Int] := option.someOf[Int](1);Reading Headers, Modules, and Packages from C++17
On the Musi side, Musi imports bring named module values into scope, so package boundaries stay visible where code uses them. Read the shared example through C++17 eyes: keep the useful instinct, then let Musi name shape, behavior, absence, and outside work in separate places.
False friend
Do not rebuild a source-language global namespace, header include pile, or barrel file when one import names the owner. For a C++ reader, the trap is turning every Musi value into a class-shaped design; Musi class is closer to a concept or trait than a C++ class; records/data store shape, instances satisfy behavior.
When this pays off
Use modules when billing, routing, text, option, runtime, or encoding code has an owner worth naming. The C++17 instinct still helps here: Keep the C++ habit of asking which operation is generic and which value owns shape.