package Foo;

use strict;
use overload '""' => \&interp;

sub new {
    my $class = shift;
    bless {
        str => $_[0],
        re  => qr/^$_[0]$/,
    }, $class;
}

sub as_string {
    $_[0]->{str};
}

sub re {
    $_[0]->{re};
}

sub interp {
    my $self = shift;
    my $condition = 1;
        # 1 if called in qr{} context
        # 0 otherwise
    $condition ? $self->re : $self->as_string;
}
1;

##</code><code>##

use Foo;

my $r = Foo->new( '[aeiou]+\\d+' );
my $super_re = qr/[A-Z]+$r/;

print <<OUT;
r     = /$r/
super = /$super_re/
OUT

for( @ARGV ) {
    my $match = ($_ =~ /$r/) ? 1 : 0;
    print "$_ match=$match\n";
}

##</code><code>##

r     = /(?-xism:^[aeiou]+\d+$)/
super = /(?-xism:[A-Z]+[aeiou]+\d+)/

##</code><code>##

r     = /(?-xism:^[aeiou]+\d+$)/
super = /(?-xism:[A-Z]+(?-xism:^[aeiou]+\d+$))/