DEFINE
  islower == ord 109.5 - abs 13 <;
  isupper == ord 77.5 - abs 13 <;
  tolower == [[isupper] [32 +] [] ifte] map;
  toupper == [[islower] [32 -] [] ifte] map.

"alphaBETA" tolower.
"alphaBETA" toupper.