不要滥造正则表达式

对于常见的问题，其实早有人写好通用模式，做成漂亮的Regex::Common 模块放在CPAN上。

Regexp::Common::balanced
Provides regexes for strings with balanced parenthesized delimiters.
Regexp::Common::comment
Provides regexes for comments of various languages (43 languages currently).
Regexp::Common::delimited
Provides regexes for delimited strings.
Regexp::Common::lingua
Provides regexes for palindromes.
Regexp::Common::list
Provides regexes for lists.
Regexp::Common::net
Provides regexes for IPv4 addresses and MAC addresses.
Regexp::Common::number
Provides regexes for numbers (integers and reals).
Regexp::Common::profanity
Provides regexes for profanity.
Regexp::Common::whitespace
Provides regexes for leading and trailing whitespace.
Regexp::Common::zip
Provides regexes for zip codes.