- 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. Specifically, they must return #t when applied to characters with the Unicode properties Alphabetic, Numeric_Type=Decimal, White_Space, Uppercase, and Lowercase respectively, and #f when applied to any other Unicode characters. Note that many Unicode characters are alphabetic but neither upper nor lower case.