repeat-statement=

  --+-----------------------+--> REPEAT --------------------+
    +-> <beginning-label>: -+                               |
  +----------------------------<----------------------------+
  +-+-> compound-use-statement --+--> UNTIL --> predicate --+
    +-------------<--------------+                          |
  +----------------------------<----------------------------+
  +---> END REPEAT --+--------------------+----------------->
                     +-> <ending-label> --+