The Lexical Class function returns the class number for char. If char is a string, this function uses the first character in the string. If char is a number, this function interprets it as the ASCII value of a character.
The class number is a number that corresponds to the lexical class. Refer to the ASCII Codes table for the numbers that correspond to each character.
||Extended characters (codes 128 through 255)
||Non-displayable ASCII characters (codes 0 to 31 excluding 9 through 13)
||White space characters: Space, Tab, Carriage Return, Form Feed, Newline, and Vertical Tab (codes 32, 9, 13, 12, 10, and 11, respectively)
||Digits 0 through 9
||Uppercase characters A through Z
||Lowercase characters a through z
||All printable ASCII non-alphanumeric characters
||More info to come.