I am not sure what exactly you are trying to do there, but the code below works for me. This is all explained in perlfunc (look for format and write) and perlform.

use strict;
use warnings;
use Diagnostics;

my @test = qw( A B C );

write;


format STDOUT =
@<< ~ Test@< = @<
@test
.
[download]

If you are not sure where to get the documentation, see How to RTFM

<cite>Just a tongue-tied, twisted, earth-bound misfit. -- Pink Floyd</cite>