#!/usr/bin/perl

use strict;
use warnings;

my ($date, $reference, $rep_line);

my $format = q/format REP_TOP =
@<<<<<<<<<<<<<<< @>>>>>>>>>>>>>>
$date, $reference
.
/;
eval $format;

$format = q/format REP =
^<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< ~~
$rep_line
.
/;
eval $format;

$date = "11/11/2011";
$reference = "REF123";

open my $fh, ">", "/tmp/test.txt" or die "$!\n";

$fh->format_name("REP");
$fh->format_top_name("REP_TOP");
$fh->autoflush(1);
$fh->format_lines_per_page(10);

for (@ARGV) {
    $rep_line = $_;
    write $fh;
}

##</code><code>##

$ perl testformat.pl 0 1 " " 2 3 " " 4 5;
$ cat /tmp/test.txt
11/11/2011                REF123
0
1
2
3
4
5

##</code><code>##

$ perl testformat.pl 0 1 " " 2 3 " " 4 5;
$ cat /tmp/test.txt
11/11/2011                REF123
0
1

2
3

4
5