- char-set:whitespaceconstant
The ASCII whitespace characters are line feed, horizontal tabulation, vertical tabulation, form feed, carriage return, and space. These are also exactly the characters recognised by the Posix isspace() procedure.
For Unicode, a character is whitespace if it has a White_Space property.
Some Unicode whitespace characters:
1680 OGHAM SPACE MARK Zs 2028 LINE SEPARATOR Zl 2029 PARAGRAPH SEPARATOR Zp