Note: Although character objects can represent all of Unicode, the model of alphabetic case used covers only ASCII letters, which means that case-insensitive comparisons and case conversions are incorrect for non-ASCII letters. This will eventually be fixed.
If char is a character representing a digit in the given radix, returns the corresponding integer value. If you specify radix (which must be an exact integer between 2 and 36 inclusive), the conversion is done in that base, otherwise it is done in base 10. If char doesn't represent a digit in base radix,
Note that this procedure is insensitive to the alphabetic case of char.(char->digit #\8) => 8 (char->digit #\e 16) => 14 (char->digit #\e) => #f
Returns a character that represents digit in the radix given by radix. Radix must be an exact integer between 2 and 36 (inclusive), and defaults to 10. Digit, which must be an exact non-negative integer, should be less than radix; if digit is greater than or equal to radix,
#f.(digit->char 8) => #\8 (digit->char 14 16) => #\E