URI_regexp.rb

/
        ([a-zA-Z][-+.a-zA-Z\d]*):                     (?# 1: scheme)
        (?:
           ((?:[-_.!~*'()a-zA-Z\d;?:@&=+$,]|%[a-fA-F\d]{2})(?:[-_.!~*'()a-zA-Z\d;\/?:@&=+$,\[\]]|%[a-fA-F\d]{2})*)              (?# 2: opaque)
        |
           (?:(?:
             \/\/(?:
                 (?:(?:((?:[-_.!~*'()a-zA-Z\d;:&=+$,]|%[a-fA-F\d]{2})*)@)?  (?# 3: userinfo)
                   (?:((?:(?:(?:[a-zA-Z\d](?:[-a-zA-Z\d]*[a-zA-Z\d])?)\.)*(?:[a-zA-Z](?:[-a-zA-Z\d]*[a-zA-Z\d])?)\.?|\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}|\[(?:(?:[a-fA-F\d]{1,4}:)*(?:[a-fA-F\d]{1,4}|\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})|(?:(?:[a-fA-F\d]{1,4}:)*[a-fA-F\d]{1,4})?::(?:(?:[a-fA-F\d]{1,4}:)*(?:[a-fA-F\d]{1,4}|\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}))?)\]))(?::(\d*))?))?(?# 4: host, 5: port)
               |
                 ((?:[-_.!~*'()a-zA-Z\d$,;:@&=+]|%[a-fA-F\d]{2})+)           (?# 6: registry)
               )
             |
             (?!\/\/))                              (?# XXX: '\/\/' is the mark for hostport)
             (\/(?:[-_.!~*'()a-zA-Z\d:@&=+$,]|%[a-fA-F\d]{2})*(?:;(?:[-_.!~*'()a-zA-Z\d:@&=+$,]|%[a-fA-F\d]{2})*)*(?:\/(?:[-_.!~*'()a-zA-Z\d:@&=+$,]|%[a-fA-F\d]{2})*(?:;(?:[-_.!~*'()a-zA-Z\d:@&=+$,]|%[a-fA-F\d]{2})*)*)*)?              (?# 7: path)
           )(?:\?((?:[-_.!~*'()a-zA-Z\d;\/?:@&=+$,\[\]]|%[a-fA-F\d]{2})*))?           (?# 8: query)
        )
        (?:\#((?:[-_.!~*'()a-zA-Z\d;\/?:@&=+$,\[\]]|%[a-fA-F\d]{2})*))?            (?# 9: fragment)
      /xn

# This regex for URI.
# I want this on T-shirt.