#! perl -slw
use strict;

sub nFor(&@) {
    my $code = shift;
    die "First argument must be a code ref" unless ref( $code ) eq 'CO
+DE';
    my @limits = @_;

    my @indices = ( 0 ) x @limits;

    for( my $i = $#limits; $i >= 0; ) {
        $i = $#limits;
        $code->( @indices ), ++$indices[ $i ]
            while $indices[ $i ] < $limits[ $i ];
        $i = $#limits;
        $indices[ $i ] = 0, ++$indices[ --$i ]
            while $i >= 0 and $indices[ $i ] == $limits[ $i ];
    }
}

my @a = 'a'..'z';
my @a3;
nFor{
    push @a3, [ @a[ @_ ] ];
} ( scalar @a ) x 3;

my @b = 0 .. 9;
my @b2;
nFor{
    push @b2, [ @b[ @_ ] ];
} ( scalar @b ) x 2;

nFor {
    print join '-', @{ $a3[ $_[0] ] }, @{ $b2[ $_[1] ] };
} scalar @a3, scalar @b2;

__END__
C:\test>965138 | wc -l
1757600

C:\test>965138
a-a-a-0-0
a-a-a-0-1
a-a-a-0-2
a-a-a-0-3
...
z-z-z-9-6
z-z-z-9-7
z-z-z-9-8
z-z-z-9-9
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