It is hard to imagine why this specific problem would have its own solution.

The problem can be generalized into something worth solving. Assume we want to divide a list on break points. I will present an iterator solution.

#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;

sub gen_divider {
    my %opt = @_;
    my $is_break = $opt{detect_break};

    my ($curr, @list);

    return sub {
        for (@_) {
            if (! defined $curr || $is_break->($_, $curr)) {
                push @list, [$_];
                $curr = $_;
            }
            else {
                push @{$list[-1]}, $_;
            }
        }
        return \@list;
    };
}

my $break_point = sub {
    my ($item_to_test, $prev_break_point) = @_;
    return $item_to_test ne $prev_break_point;
};

my $divide = gen_divider(detect_break => $break_point);

for (split //, "ZBBBCZZ") {
    $divide->($_);
}

my $list = $divide->();
print Dumper($list);
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