http://www.perlmonks.org?node_id=481151


in reply to Sudoku generator

Instead of 
die "ASSERT( $row, $col )" unless Crd2Index( $row, $col ) < Squared;

[download]
why not use Carp::Assert : 
use Carp::Assert;

...

assert(Crd2Index( $row, $col ) < Squared, 
       "Crd2Index( $row, $col ) < Squared") if DEBUG;

[download]

Also see Gratuitous use of Perl Prototypes

In Section Cool Uses for Perl