   PERFORM
   ~~~~~~~
    [ { [ WITH TEST { BEFORE } ] { VARYING-Clause                 } } ]
      {        ~~~~ { ~~~~~~ }   { UNTIL conditional-expression-1 } }
      {             { AFTER  }     ~~~~~                            }
      {               ~~~~~                                         }
      { UNTIL EXIT|FOREVER                                          }
      { ~~~~~ ~~~~ ~~~~~~~                                          }
      { { literal-1    } TIMES                                      }
      { { identifier-1 } ~~~~~                                      }

      imperative-statement-1

 [ END-PERFORM ]
   ~~~~~~~~~~~