L'operatore di trasferimento

Passing to an owned parameter usually makes a copy. But if you are done with the original, copying is wasteful. You can move it instead. 🚚

Mojo's transfer operator is the caret ^ sigil. You place it after a value to hand its ownership over instead of duplicating it.

Add ^ when calling a function with an owned parameter. The value transfers in, and no copy is made.

After a transfer, the source variable is no longer valid. Mojo ends its lifetime, so you cannot accidentally use the moved value.

Try to read a variable after moving it and the compiler rejects your code. This check stops use-after-move bugs before they run.

A move just transfers ownership of the existing data. There is no deep copy, which matters a lot for big strings, lists, or buffers.

Without ^ Mojo copies into an owned parameter; with ^ it moves. You decide based on whether you still need the original.

The caret also works between variables. Writing one var from another with ^ moves the value rather than copying it across.

The transfer operator is the natural partner of owned parameters. Together they express giving a value away cleanly and cheaply.

Moves give you C-like efficiency while the compiler guarantees you never touch a value after handing it off. That is safe and fast.

borrowed, inout, owned, and the ^ transfer together let you control exactly how data flows through your program, with no surprises.

Let us check what the ^ operator does to the source.

The ^ transfer operator moves a value instead of copying it, ending the source's life. Paired with owned, it makes giving data away fast and safe. 🎯