It's a big ugly, but you can use select and $~ to change the format for a given filehandle. See perlform for more info. In the meantime, here is a brief example:

use strict;
use warnings;

open( my $outfh, '>', 'temp.txt' ) or die $!;

my ( $var1, $var2 ) = ( 'one', 'two' );

my $oldfilehandle = select $outfh;
$~ = "FORMAT1";
select $oldfilehandle;
write $outfh;

$oldfilehandle = select $outfh;
$~ = "FORMAT2";
select $oldfilehandle;
write $outfh;

$oldfilehandle = select $outfh;
$~ = "FORMAT1";
select $oldfilehandle;
write $outfh;


format FORMAT1 =
    @<<<<<   @<<<<<
    $var1,   $var2
.

format FORMAT2 =
    @<<<<<XXX@<<<<<
    $var2,   $var1
.

close $outfh;
[download]

    one      two
    two   XXXone
    one      two
[download]

This is exactly what I wanted! I read perlform, but didn't understand it. Your example it so much clearer!

Thanks!

Just select the format you like assigning to $~. Example:

#!/usr/bin/perl

our(@l,$c);
while(@l = getpwent) {
    $~ = $c++ % 2 ? 'foo' : 'bar';
    write;
}

format foo =
left @<<<<<<<<<<<< @<<<<<<<<<<<<
$l[0],$l[7]
.
format bar =
right @>>>>>>>>>>> @>>>>>>>>>>>>
$l[0],$l[7]
.
[download]

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

I kind of doubt you can do what you asked for. The replacement for that in perl 6 is also available in perl 5 with Perl6::Form.