Ownership capabilities

Z makes consequential ownership operations readable where they occur while inferring lexical lifetimes internally.

Capability	Meaning	Typical use
in	Immutable borrow	Inspect a value without taking ownership
inout	Exclusive mutable borrow	Mutate caller-owned storage
out	Write-only initialization borrow	Let a callee initialize storage
move	Transfer ownership	Hand a move-only value to a new owner
copy	Explicitly duplicate a copyable value	Preserve the source and create an independent value
view	Non-owning projection tied to an owner	Inspect interior storage without copying

struct Counter { count: i32; }

function inspect(in counter: Counter): i32 {
  return counter.count;
}

function increment(inout counter: Counter): void {
  counter.count += 1;
}

let counter = Counter({ count: 0 });
increment(inout counter);

Immutable in is normally inferred at a call site. Writable inout, out, move, and copy remain explicit because they change storage or ownership.

Views

A view borrows part of an owner without retaining or copying it:

function first(in library: Library): view Document {
  return library.documents[0];
}

The compiler prevents the view from outliving or being invalidated by its owner. Current rules are intentionally conservative and grow only when Z can prove a more permissive shape safe.

Deterministic cleanup and shared identity

Move-only values and native resources can define deinit for deterministic cleanup. ARC-managed classes provide shared identity; Weak<T> provides a non-owning reference that must be upgraded before use. Cross-thread shared mutation goes through synchronization such as Mutex<T> or executor isolation, not unrestricted aliases.