Ownership and borrowing

Goal

No allocation that a borrow would cover. Shared mutability only when the type system requires it.

Inputs / outputs

• In: a function or type that owns or shares data
• Out: API that takes the least ownership it needs

Reads / writes

• Read: the function and its callers
• Write: none unless a playbook opened the task

Approval

None to drop clones. Stop for approval before adding Arc, Rc, Mutex, RwLock, or RefCell.