Sure, you can get by with one global by using the empty first place in the global @l.

#!/usr/bin/perl -w -p
s/^(\*+)/
# use only one global by using empty first place in @l
my $n = length($1);
$n < $l[0] ? @l[$n+1..$#l] = (0)x($#l-$n) : 0;
$l[$n]++;
$l[0] = $n;
join(".",@l[1..$n]);
/e;
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Christian Lemburg
Brainbench MVP for Perl
http://www.brainbench.com