loop { block } // infinite loop
while condition { block }
while let pattern = expr { block }
for pattern in expr { block } // expr must implement IntoIterator
continue // jump to the end of the loop body, starting a new iteration if necessary
break // stop the loop
'label: loop { block }
'label: while condition { block }
'label: while let pattern = expr { block }
'label: for pattern in expr { block }
continue 'label // jump to the end of the loop body labelled label, starting a new iteration if necessary
break 'label // stop the loop labelled label