this check '$argv[0] <> "0"' doesn't make much sense here, since 001 is a valid way to represent a positive integer. IMHO the new function is not necessary and I cannot see other uses for this. You can have a local function on firewall_rules_edit.php that checks something like:
```
if (is_numericint($value) && $value[0] != '0' && $value > 0)
```