loop

loop creates an unconditional infinite loop. It runs until a break exits it. Prefer loop over while true — it states the intent directly and cannot be mistaken for a condition that might change.

loop {
    let input = ReadLine();
    if input == "quit" { break; }
    Process(input);
}

Labels

A loop can be given a label so that break and continue target a specific outer loop when loops are nested. A label is a name followed by : before the loop:

outer: loop {
    loop {
        if ShouldStop() { break outer; }
        if ShouldSkip() { continue outer; }
        Step();
    }
    // never reached after `break outer`
}

break outer exits the labeled loop entirely. continue outer skips to the next iteration of the labeled loop. Without a label, break and continue always act on the innermost loop.

Labels work on any loop — loop, while, and for — not only on loop.

See Also

• break / continue — exiting and skipping iterations
• while — looping while a condition holds