Handlers/demo/Demo.pm

$DB::single = 1;

package Demo;
$VERSION = '1.00';
use Attribute::Handlers;
no warnings 'redefine';

sub Demo : ATTR(SCALAR) {
    my ($package, $symbol, $referent, $attr, $data, $phase) = @_;
    $data = '<undef>' unless defined $data;
    print STDERR 'Scalar $', *{$symbol}{NAME},
             " ($referent) was ascribed ${attr}\n",
             "with data ($data)\nin phase $phase\n";
};

sub This : ATTR(SCALAR) {
    print STDERR "This at ",
             join(":", map { defined() ? $_ : "" } caller(1)),
             "\n";
}

sub Demo : ATTR(HASH) {
    my ($package, $symbol, $referent, $attr, $data) = @_;
    $data = '<undef>' unless defined $data;
    print STDERR 'Hash %', *{$symbol}{NAME},
             " ($referent) was ascribed ${attr} with data ($data)\n";
};

sub Demo : ATTR(CODE) {
    my ($package, $symbol, $referent, $attr, $data) = @_;
    $data = '<undef>' unless defined $data;
    print STDERR 'Sub &', *{$symbol}{NAME},
             " ($referent) was ascribed ${attr} with data ($data)\n";
};

sub Multi : ATTR {
    my ($package, $symbol, $referent, $attr, $data) = @_;
    $data = '<undef>' unless defined $data;
    print STDERR ref($referent), ' ', *{$symbol}{NAME},
             " ($referent) was ascribed ${attr} with data ($data)\n";
};

sub ExplMulti : ATTR(ANY) {
    my ($package, $symbol, $referent, $attr, $data) = @_;
    $data = '<undef>' unless defined $data;
    print STDERR ref($referent), ' ', *{$symbol}{NAME},
             " ($referent) was ascribed ${attr} with data ($data)\n";
};

1;