#! /usr/bin/perl -w

use strict;

sub neighbourhood {
    my $dim = shift;
    my @current = (-1) x $dim;
    my $done = 0;
    return sub {
         return if $done;
         my @res = @current;
         my $i;
         ITER: for ($i = 0; $i < scalar @current; ++$i) {
             if (++$current[$i] > 1 ) {
                 $current[$i] = -1;
             } else {
                 my $not_origin = 0;
                 ($current[$_] != 0 and $not_origin = 1)
                     for @current;
                 redo ITER unless $not_origin;
                 last;
             }
         }
         $done = 1 if $i >= scalar @current;
         return @res;
    }
}

my $iter = neighbourhood( shift || 3 );

while( my @iter = $iter->() ) {
    print "@iter\n";
}

##</code><code>##

#! /usr/bin/perl -w

use strict;

sub neighbourhood {
    my @origin = @_;
    my $dim = scalar @origin;
    my @current = (-1) x $dim;

    my $done = 0;
    return sub {
         return if $done;
         my @res = @current;
         my $i;
         for ($i = 0; $i < scalar @current; ++$i) {
             $res[$i] += $origin[$i];
         }
         ITER: for ($i = 0; $i < scalar @current; ++$i) {
             if (++$current[$i] > 1 ) {
                 $current[$i] = -1;
             } else {
                 my $not_origin = 0;
                 ($current[$_] != 0 and $not_origin = 1)
                     for @current;
                 redo ITER unless $not_origin;
                 last;
             }
         }
         $done = 1 if $i >= scalar @current;
         return @res;
    }
}

@ARGV = (6, 2, -4) unless @ARGV;

my $iter = neighbourhood( @ARGV );
while( my @iter = $iter->() ) {
        print "@iter\n";
}