borrowing

The concept of "borrowing" in Swift is discussed in the context of ownership and memory management. Borrowing a value means asserting that nobody else can consume or mutate it, which is useful when you just want to read a value without altering it. This is a common practice when passing arguments, as it allows you to pass information without additional overhead. However, Swift sometimes needs to defensively copy arguments instead of borrowing them, especially in complex scenarios where it cannot guarantee that the value won't be mutated or consumed elsewhere.

For more details, you can refer to the session "Explore Swift performance" where borrowing is discussed in the context of Swift's ownership system. You can find this discussion in the chapter on Value copying.

Additionally, the session "Consume noncopyable types in Swift" also touches on borrowing in the context of noncopyable types, explaining how borrowing provides read access similar to a let binding. This is covered in the chapter on Noncopyable Types.