# ! perl -slw
use strict;

sub nForS(&$@) {
    my $code = shift;    die "First argument must be a code ref"   unless ref( $code ) eq 'CODE';
    my $aref = shift;    die "second argument must be an array ref" unless ref( $aref ) eq 'ARRAY';

    my @limits = @_;

    our @indices; local *indices = $aref;

    @indices = ( 0 ) x @limits unless @indices;

    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 @state;
my $n = 10;
nForS{ print "@_\n"; last unless --$n } \@state, 3, 6, 9;

print "First 10 permutations; enter to see the rest"; <STDIN>;

nForS{ print "@_\n"; } \@state, 3, 6, 9;

##</code><code>##

C:\test>junk
0 0 0
0 0 1
0 0 2
0 0 3
0 0 4
0 0 5
0 0 6
0 0 7
0 0 8
0 1 0
First 10 permutations; enter to see the rest
0 1 0
0 1 1
0 1 2
0 1 3
...
2 5 6
2 5 7
2 5 8

##</code><code>##

# ! perl -slw
use strict;

sub nForS(&$@) {
    my $code = shift;    die "First argument must be a code ref"   unless ref( $code ) eq 'CODE';
    my $aref = shift;    die "Second argument must be an array ref" unless ref( $aref ) eq 'ARRAY';

    my @limits = @_;

    our @indices; local *indices = $aref;

    @indices = ( 0 ) x @limits unless @indices;

    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 @state;

my @alpha =  'a'..'z';
my @nums = 10 .. 20;
my @rands = map rand, 1 .. 10;

my $n = 23;
nForS{
    print "$alpha[ $_[0] ] $nums[ $_[1] ] $rands[ $_[2] ] \n";
    last unless --$n;
} \@state, 26, 11, 10;

print "First 23 perms; enter to continue"; <STDIN>;

nForS{
    print "$alpha[ $_[0] ] $nums[ $_[1] ] $rands[ $_[2] ] \n";
} \@state, 26, 11, 10;

__DATA__
C:\test>junk
a 10 0.69268798828125
a 10 0.297698974609375
a 10 0.94830322265625
a 10 0.024749755859375
a 10 0.934661865234375
a 10 0.614898681640625
a 10 0.361328125
a 10 0.20947265625
a 10 0.556488037109375
a 10 0.879547119140625
a 11 0.69268798828125
a 11 0.297698974609375
a 11 0.94830322265625
a 11 0.024749755859375
a 11 0.934661865234375
a 11 0.614898681640625
a 11 0.361328125
a 11 0.20947265625
a 11 0.556488037109375
a 11 0.879547119140625
a 12 0.69268798828125
a 12 0.297698974609375
a 12 0.94830322265625
First 23 perms; enter to continue
a 12 0.94830322265625
a 12 0.024749755859375
a 12 0.934661865234375
a 12 0.614898681640625
a 12 0.361328125
a 12 0.20947265625
a 12 0.556488037109375
...