>>-LOWER(string-+----------------------------+--)--------------><
+--,--+-----+--+-----------+-+
+--n--+ +--,length--+
Example 7.56. Builtin function LOWER
lower("Albert Einstein") -> "albert einstein"
lower("ABCDEF", 4) -> "ABCdef"
lower("ABCDEF", 3, 2) -> "ABcdEF"