seq_1    1    33    gene
seq_1    1    20    exon
seq_1    21    27    exon
seq_1    28    33    exon
seq_2    1    80    gene
seq_2    1    80    exon
seq_3    1    55    gene
seq_3    1    30    exon
seq_3    31    50    exon

##</code><code>##

use Tie::File;

tie my @data, 'Tie::File', "datafile";
print "Rec$_\n$data[$_]\n\n" for (0..$#data);

##</code><code>##

Rec1
seq_1    1    33    gene
seq_1    1    20    part
seq_1    21    27    part
seq_1    28    33    part

Rec2
seq_2    1    80    gene
seq_2    1    80    part

Rec3
seq_3    1    55    gene
seq_3    1    30    part
seq_3    31    50    part

##</code><code>##

sub _read_record {
  my $self = shift;
  my $rec;
  { local $/ = $self->{recsep};
    my $fh = $self->{fh};
    $rec = <$fh>;
  }

## Rest of the subroutine...

}

##</code><code>##

sub get_next_rec
  {
    my $self = shift;
    local $/ = $self->{recsep};
    my $fh = $self->{fh};
    $rec = <$fh>;
  }

sub _read_record {
  my $self = shift;

  my $rec = $self->get_next_rec();

## Rest of the subroutine...

}

##</code><code>##

package Tie::File::GFF;

use strict;
use warnings;
use base "Tie::File";

sub get_next_rec
  {

  ## Any way of reading records of a file, for example:

    my $self = shift;
    my $fh = $self->{fh};
    return undef if (eof $fh);
    my ($last_seen,$last_pos,$rec);
    while (<$fh>){
      my @f = split /\t/;
      $last_seen = $f[0] if (! defined $last_seen);
      if ($f[0] eq $last_seen){
    $rec.=$_;
    $last_pos = int (tell $fh);
    return $rec if (eof $fh);
    next;
      } else {
    seek $fh, $last_pos, 0;
    return $rec;
      }
    }
  }

1;

##</code><code>##

use Tie::File::GFF;

tie my @data, 'Tie::File::GFF', "datafile";
print "Rec$_\n$data[$_]\n\n" for (0..$#data);

##</code><code>##

Rec1
seq_1    1    33    gene
seq_1    1    20    part
seq_1    21    27    part
seq_1    28    33    part

Rec2
seq_2    1    80    gene
seq_2    1    80    part

Rec3
seq_3    1    55    gene
seq_3    1    30    part
seq_3    31    50    part

##</code><code>##

sub get_next_rec
  {
    my $self = shift;
    local $/ = $self->{recsep};
    my $fh = $self->{fh};
    $rec = <$fh>;
  }

sub _read_record {
  my $self = shift;

  $self =~ /^(.+)=/;
  my $_caller_pack = $1;
  my $rec;
  if ($_caller_pack ne __PACKAGE__){
    $rec = $self->get_next_rec();
  } else

  { local $/ = $self->{recsep};
    my $fh = $self->{fh};
    $rec = <$fh>;
  }

## Rest of the sub

}