package Jan99;

sub new { bless({ on=>1 }, shift) }
sub log { my $self=shift; $self->{on}=shift if @_; return $self->{on}; }
sub shell { my $self=shift; $self->{on}=shift if @_; return $self->{on}; }

package Besser;
sub new { bless({ log_on => 1, shell_on => 1 }, shift) }
sub log { my $self=shift; $self->{log_on}=shift if @_; return $self->{log_on}; }
sub shell { my $self=shift; $self->{shell_on}=shift if @_; return $self->{shell_on}; }

package main;
use 5.14.0;

sub show {
    my $t = shift;
    say "Log: ", $t->log(), ", Shell: ", $t->shell();
}

sub test {
    my $t = shift;
    say "Original: "; show($t);
    say "Setting log(0)"; $t->log(0); show $t;
    say "Setting shell(1)"; $t->shell(1); show $t;
    say "Setting log(1)"; $t->log(1); show $t;
}

say "Testing Jan99"; test(Jan99->new());
say "Testing Besser"; test(Besser->new());