# loop loop

## Function
`loop` is a reserved compatibility form for an unconditional infinite loop. New code can also use `for {}` to express an infinite loop.

## Syntax
```bt
loop {
    if condition {
        break
    }
}

loop:label {
    continue:label
}
```

## Example
```bt
i = 0
loop {
    if i >= 3 {
        break
    }
    println i
    i += 1
}
```

## Notes
- It is recommended to use `for {}` first for new codes, and `loop` will continue to be compatible.
- `loop` usually must be matched with `break` in the loop body, otherwise the program will keep running.
- `continue` will skip the subsequent statements of this round and go directly to the next round.
- The `loop` statement itself returns `empty`.