sub new {
        my $proto = shift;
        my $class = ref($proto) || $proto;
        my $self  = {};
        bless ($self, $class);
        return $self;
}

##</code><code>##

sub file {
        my $self = shift;
        if (@_) {
                $self->{file} = shift;
        }
}

##</code><code>##

sub _common {
        my $self = shift;
        (my $key = (caller(1))[3]) =~ s/.*:://;

        if (@_) {
                $self->{$key} = shift;
        }
        else {
                $self->{$key}->($self) if defined $self->{$key};
        }
}

##</code><code>##

sub _common {
        my $self = shift;
        my $key  = shift;
# ...

##</code><code>##

sub pre {
        my $self = shift;
        $self->_common(pre => @_);
}
# etc.

##</code><code>##

        $self->pre();
        open my $fh, '<', $self->{file} or croak "could not open $self->{file}: $!";
        while (my $record = <$fh>) {
                chomp $record;
                $self->{record} = $record;
                $self->loop();
                $self->{hash}{ $self->{key} } = $self->{value};
                ++$self->{count};
        }
        $self->post();

##</code><code>##

                my %data = $self->loop();
                @{$self->{hash}{keys %data}} = values %data;
                $count += scalar keys %data;