19 - Regexp::Common

my $number   = qr/[+-]?(?-\d|[.]\d)\d*)?:[.]\d*)?(?:[Ee][+-]?\d+)?/;

my $comment  = qr/(?s)/\/(?:\/[^\n]\n|\*.*?\*\/)/;

my $http     = qr/(?ix)https?://(?:[^:]+(?::[^@]+)?(?:[a-z0-9]
                 (?:[a-z0-9]+-[a-z0-9])*\.)+(?:[a-z0-9](?:[a-z0-9]+
                 |-[a-z0-9])*)(?::\d+)?(?:/\S*)?(?=[.>'"\s]|$)/;

my $string   = qr/'[^'\\]*(?:\\.[^'\\]*)*'/;


use Regexp::Common;
my $number  = $RE{num}{real};

my $comment = $RE{comment}{'C++'};

my $http    = $RE{net}{url}{http};

my $string  = $RE{delimited}{-delim=>q{"}};