It seems to me that validating on the AST would be a lot cleaner/saner (if int(ipv4addr) > 256: err), and generally allow for much better error messages; especi

It seems to me that validating on the AST would be a lot cleaner/saner (if int(ipv4addr) > 256: err), and generally allow for much better error messages; especially since you'll be doing almost all your validations on the AST anyways. It would ofc also be more useful in future parsing too (similar structure, but not ipv4), but thats a much more minor and rarer benefit