DouKaku?

#!/usr/local/bin/perl
use strict;
use warnings;
s/(.)/do{no warnings 'syntax';my %c=qw!
< $p--;
> $p++;
+ $d[$p]++;
- $d[$p]--;
. print(chr$d[$p]);
, $d[$p]=getc;
[ while($d[$p]){
] }
!;\%c}->{$1}/egx and print for(<>);