package Data::CryptRecord;
BEGIN {
    use strict;
    [ ... ]
    our %ENGINES;
}

sub register { ... } # adds to the %ENGINES hash

# List what's in the hash
sub list_engines {
    my $self = shift;

    my @eng;
    while( my ($k, $v) = each(%ENGINES)){
        push @eng, $v->{'name'};
    }

    return @eng;
}

# Chose a distinct crypt method for this instance
# Lot's of list_engines included for debugging
sub set_engine {
    my ($self, $name) = @_;
    
    $name = uc($name);
    print "Enter set_engine (" . scalar $self->list_engines . ")\n";
    while( my ($k, $v) = each(%ENGINES)){
        next unless(uc($v->{'name'}) eq $name);
        $self->{'enc_type'} = $k;
        print "Exit OK set_engine (" . scalar $self->list_engines . ")\n";
        return 0;
    }
    print "Exit fail set_engine (" . scalar $self->list_engines . ")\n";
    return -1;
}

##</code><code>##

(not shown, at the end of the CTOR)
Blessed List(1)
Enter set_engine(1)
Exit OK set_engine (0)
after set_list (1)
(This is another list_engines called later in the program)

##</code><code>##

export PERLDB_OPTS='TTY=/dev/pts/2'
perl -d ./myprg.pl