hpush -- like 'push' for a hash

hpush.pm

package hpush;

use base 'Exporter';
our @EXPORT = ('hpush');

use strict;
use warnings;

sub hpush (\%@) {
    my $h = shift;
    foreach (@_) {
	$h->{$_} = 1;
    }
}

1;

output.log

$ perl test.pl 
1
1,2,3
1,2,3,5
$ 

test.pl

use strict;
use warnings;

use hpush;

my %h = ();

hpush %h, 1;
print join(',', sort keys %h), "\n";

hpush %h, 2, 3;
print join(',', sort keys %h), "\n";

hpush %h, 1,3,5;
print join(',', sort keys %h), "\n";