Hi MaxKlokan,

why does the following code give the warnings below

From the documentation:

“If you put two contiguous tilde characters "~~" anywhere into a line, the line will be repeated until all the fields on the line are exhausted, i.e. undefined.”

In your example, it prints the first line without problem. For the second line, the last field is undefined (shift @a returns undefined). For the third line, all the fields return undefined, so it stops repeating the line.

I am not sure if this would help, but you could try something like:

#!/usr/bin/perl
use strict;
use warnings;
my @a = qw/one two three four five six seven /;
$~ = "TEST";
print "---+++---\n";
my ($a1, $a2, $a3);
while (@a) {
  $a1 = shift @a || "empty";
  $a2 = shift @a || "empty";
  $a3 = shift @a || "empty";
  write;
}
print "---------\n";
format TEST =
a: @* @* @*
   $a1, $a2, $a3
.
[download]

Output:

---+++---
a: one two three
a: four five six
a: seven empty empty
---------
[download]

Cheers,

lin0

PS: I do not get any warning running your code with Perl 5.8.7