in reply to Multi-dimensional constants

I would recommend trying `Readonly'.

use Readonly; Readonly my @readonly => (['book', 'pen', 'pencil'], ['bat', 'ball', 'glove'], ['snake', 'rat', 'rabbit']); print $readonly[0][0], "\n"; $readonly[0][0] = "comicbook"; 1;

Outputs the following:
book
Modification of a read-only value attempted at ./readonly.pl line 11
Plus you should be able to fill in the array at runtime so that should give you more flexibility.