Repeated block execution

loop { ... } runs its block until break. A break value becomes the result, and a bare break gives nil; the signature is loop(&block: ()) -> any, so narrow the result or declare the local it is stored in. next starts another iteration, discarding its value, and ordinary block results are discarded too. A return leaves the enclosing function, and every control transfer honors ensure clauses.

count = 0
result = loop {
  count += 1
  next if count < 3
  break count * 10
}
result # 30

The block receives no arguments. Calls reject positional arguments and keywords, and loop without a block is a compile error (V0304). Script functions can shadow the global helper under the usual name-resolution rules.

loop is a direct call target and cannot be read as a value. Its native frame holds the block and call roots for the duration of execution, charges work on every iteration and uses the recursion limit. Discarded results are released before the next block call; retained results continue consuming the memory budget. Cancellation and exhausted limits remain uncatchable and prevent subsequent rescue or ensure effects.

A { after a call starts its block, so a block’s first statement never reads as a hash entry: loop { break :done } breaks with the symbol.