This does not work for some strings.

$string = "(1,2,3,<4,5,6>),more";
my @line = split(/,(?![\w,]+[>)])/, $string);

print Dumper(\@line);
[download]

produces

$VAR1 = [
          '(1',
          '2',
          '3',
          '<4,5,6>)',
          'more'
        ];
[download]

The problem is any commented comma that is followed by an opening delimiter before a closing delimiter. I suspect it is not possible to generalize the solution without counting the delimiters.