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Returns the uppercase or lowercase equivalent of char if char is a letter; otherwise returns char. These procedures return a character char2 such that
(char-ci=?
char char2)
.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,
char->digit
returns#f
.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,
digit->char
returns#f
.(digit->char 8) => #\8 (digit->char 14 16) => #\E