#!/usr/bin/perl
use strict;
use warnings;

my %seen;
for my $file (@ARGV) {
    open(my $fh, '<', $file) or die "Unable to open '$file' for reading: $!";
    while (<$fh>) {
        my ($set) = $_ =~ /^(\w+)/;
        powerset($set);
    }
}
sub powerset {
    my $set = shift @_;
    return if $seen{$set}++;
    print "$set\n";
    powerset($_) for subsets($set);
}

##</code><code>##

sub subsets {
    my $set = shift @_;
    return if length($set) == 1;
    my ($head, $char, $tail) = ($set, '', '');
    my @ret;
    while ($head) {
        $char = chop $head;
        push @ret, $head . $tail;
        $tail = $char . $tail;
    }
    return @ret;
}

##</code><code>##

sub subsets {
    my $set = shift @_;
    return if length($set) == 1;
    my @list = split //, $set;
    my $pos = @list;
    my @ret;
    while ($pos--) {
        push @ret, join '', @list[grep $_ != $pos, 0 .. $#list];
    }
    return @ret;
}

##</code><code>##

# All references to $calls removed

# $limbic_sets = [ ... ]
# foreach my $limbic_set (@$limbic_sets) { ... }

# The above two lines became
open(my $fh, '<', 'phase1.data') or die $!;
while ( <$fh> ) {
    my ($limbic_set) = $_ =~ /^(\w+)/;
    $limbic_set = [ split //, $limbic_set ];
    # ...
}

# removed print "checks set @$limbic_set\n";

# my $format = "%2s" x scalar(@$padded_limbic_set) . " (%d)\n";
# printf($format, (map {defined $_ && $display->{$_} ? $_ : ' '} @$padded_limbic_set), $idx);

# The above 2 lines became
print join '', map {defined $_ && $display->{$_} ? $_ : ''} @$padded_limbic_set;
print "\n";