#! perl -slw
use strict;

use Algorithm::Loops qw( NestedLoops );

sub nFor(&@) {
    my $cb = shift;
    NestedLoops([ map [ 0..$_-1 ], @_ ], $cb);
}

my @digits = 1 .. 3;

nFor {
    print join '', @digits[ @_ ];
} ( 3 ) x 4;