-/* LOOP outputs a transformation that is executed only on the
- first pass through the loop. On this trip, it initializes for
- the first pass by resetting the pass number, setting up the
- indexing clause, and testing the LOOP IF clause. If the loop
- is not to be entered at all, it jumps forward just past the
- END LOOP transformation; otherwise, it continues to the
- transformation following LOOP.
-
- END LOOP outputs a transformation that executes at the end of
- each trip through the loop. It checks the END LOOP IF clause,
- then updates the pass number, increments the indexing clause,
- and tests the LOOP IF clause. If another pass through the
- loop is due, it jumps backward to just after the LOOP
- transformation; otherwise, it continues to the transformation
- following END LOOP. */
-