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That doesn’t answer the question. By “validate”, I mean “prove to yourself that the regular expression is correct”. Much like with program code, you can’t do that by only testing it. You need to understand what the expression actually says.


Testing something is the best way to prove that it behaves correctly in all the cases you can think of. Relying on your own (fallible) understanding is dangerous.

Of course, there may be cases you didn't think of where it behaves incorrectly. But if that's true, you're just as likely to forget those cases when studying the expression to see "what it actually says". If you have tests, fixing a broken case (once you discover it) is easy to do without breaking the existing cases you care about.

So for me, getting an AI to write a regex, and writing some tests for it (possibly with AI help) is a reasonable way to work.


I don’t believe this is true. That’s why we do mathematical proofs, instead of only testing all the cases one can think of. It’s important to sanity-check one’s understanding with tests, but mere black-box testing is no substitute for the understanding.


Code is not perfect like math imho

libraries some times make weird choices

in theory theory and practice are the same, in practice not really

in the context of regex, you have to know which dialect and programming language version of regex you’re targeting for example. its not really universal how all libs/languages works

thus the need to test




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