my ($row,$col) = ('a',0);
my $total_cols = $table->get_col_count();

$table->map_cell( sub {
   my $old = shift;

   $col++;
   my $new = qq|<input type="text" name="_$row$col" value="$old">|;

   $row++ and $col = 0 unless $col % $total_cols;
   return $new;
});