19.5 | Module `Char`: character operations

    val code : char -> int

> Return the ASCII code of the argument.

    val chr: int -> char

> Return the character with the given ASCII code. Raise `Invalid_argument "Char.chr"` if the argument is outside the range 0--255.

    val escaped : char -> string

> Return a string representing the given character, with special characters escaped following the lexical conventions of Objective Caml.

    val lowercase: char -> char
    val uppercase: char -> char

> Convert the given character to its equivalent lowercase or uppercase character, respectively.