I'm completely stunned that you'd suggest not
using regexes for parsing. They might be hard to get "right", but I assure you, getting the same effect with ord
is going to be a struggle you don't want to pursue.
Peer review and a huge number of test cases, especially those culled from real-world experience, can help make your validation routine more robust. For example, check through your current database and make sure everything passes before unleashing your validator on the Web site. It's really unpleasant to find out that Really Important Customer XYZ can't post their Really Big Order because their part number has a dash in it, and your validator rejects that as invalid.