- char-alphabetic? charprocedure
- char-numeric? charprocedure
- char-whitespace? charprocedure
- char-upper-case? letterprocedure
- char-lower-case? letterprocedure
These procedures return #t if their arguments are alphabetic, numeric, whitespace, upper case, or lower case characters, respectively, otherwise they return #f. The following remarks, which are specific to the ASCII character set, are intended only as a guide: The alphabetic characters are the 52 upper and lower case letters. The numeric characters are the ten decimal digits. The whitespace characters are space, tab, line feed, form feed, and carriage return.