Why didn't anyone ever let me know that these posix classes existed ?

POSIX	Description	ASCII	Unicode	Shorthand	Java
[:alnum:]	Alphanumeric characters	[a-zA-Z0-9]	[\p{L&}\p{Nd}]		\p{Alnum}
[:alpha:]	Alphabetic characters	[a-zA-Z]	\p{L&}		\p{Alpha}
[:ascii:]	ASCII characters	[\x00-\x7F]	\p{InBasicLatin}		\p{ASCII}
[:blank:]	Space and tab	[ \t]	[\p{Zs}\t]	\h	\p{Blank}
[:cntrl:]	Control characters	[\x00-\x1F\x7F]	\p{Cc}		\p{Cntrl}
[:digit:]	Digits	[0-9]	\p{Nd}	\d	\p{Digit}
[:graph:]	Visible characters (i.e. anything except spaces, control characters, etc.)	[\x21-\x7E]	[^\p{Z}\p{C}]		\p{Graph}
[:lower:]	Lowercase letters	[a-z]	\p{Ll}		\p{Lower}
[:print:]	Visible characters and spaces (i.e. anything except control characters, etc.)	[\x20-\x7E]	\P{C}		\p{Print}
[:punct:]	Punctuation and symbols.	[!"#$%&'()*+,	[\p{P}\p{S}]		\p{Punct}
		\-./:;<=>?@
		[\\\]^_`{\|}~]
[:space:]	All whitespace characters, including line breaks	[ \t\r\n\v\f]	[\p{Z}\t\r\n\v\f]	\s	\p{Space}
[:upper:]	Uppercase letters	[A-Z]	\p{Lu}		\p{Upper}
[:word:]	Word characters (letters, numbers and underscores)	[A-Za-z0-9_]	[\p{L}\p{N}\p{Pc}]	\w
[:xdigit:]	Hexadecimal digits	[A-Fa-f0-9]	[A-Fa-f0-9]		\p{XDigit}

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