use Algorithm::Loops qw( NestedLoops );

my %params = (
  x_pos => [1..10],
  y_pos => [-5..5],
  z_pos => [0..15],
  spin  => [0, 1],
  neato => [1..10],
);

my @keys = keys %params;

NestedLoops(
   [ @params{@keys} ],
   sub { function(map { $keys[$_], $_[$_] } 0..$#keys) }
);

sub function {
   my %args = @_;
   print(join(', ', map { "$_ => $args{$_}" } keys %args), "\n");
}

##</code><code>##

use Algorithm::Loops qw( NestedLoops );

my @params = (
  [1..10],
  [-5..5],
  [0..15],
  [0, 1],
  [1..10],
);

NestedLoops(\@params, \&function);

sub function {
   print(join(', ', @_), "\n");
}