3 ms·

Regexes are easy to test. Bad developers do bad regexes, regardless of whether they used AI.

by mFixman 2y ago

Etherlord87 2y ago
How do you test a regex to be 100% sure it's valid? I don't think it's possible.
- fkyoureadthedoc 2y ago
  True for most things I think
- eutropia 2y ago
  If it's using classical regex, without backtracking or other extensions, a regular expression is isomorphic to a state machine. You can enumerate combinations doing something like this: https://stackoverflow.com/a/1248566 https://stackoverflow.com/a/1248566 kids these days and their lack of exposure to finite automata
  - Etherlord87 2y ago
    - Vehicle steering is easy to test. - How so? I don't think it's possible to test for all cases... - Well, it's easy, assuming a car on a non-branching track, moving with a constant speed and without any realistic external influences on it, you can simply calculate the distance traveled using the formula s = v/t. Ah, I wish I'd stop running into fools not knowing Newton's first law of motion... - ??? Are you well?
    - loamaa 2y ago
      I understand you want to refute/diminish the parent comment on finite automata, but I think you are providing a straw man argument. The parent comment does provide an interesting, factual statement. I don't believe finite state automata are at all close in complexity to real-world self-driving car systems (or even a portion thereof). Your closing statement is also dismissive and unconstructive. I believe finite state modeling is used at NASA, A google search brings up a few references (that I'm probably not qualified to speak to), and I also remember hearing/reading a lecture on how they use them to make completely verifiable programs but can't find the exact one at the moment.
      - Etherlord87 2y ago
        I wasn't making a strawman, I was making a parody of his strawman. I thought it's obvious, since I was making an analogy, and it was an analogy to his argument.
    - eutropia 2y ago
      I should have been more clear perhaps: many regexes are capable of being verified with 100% certainty: https://en.m.wikipedia.org/wiki/Thompson%27s_construction https://en.m.wikipedia.org/wiki/Thompson%27s_construction But not all regexes (eg, those using PCRE extensions afaik) are amenable to such a treatment. Those you just tend to hope they work.
- spurgu 2y ago
  Aren't you asking how to create software without bugs?
  - Etherlord87 2y ago
    Well regex isn't Turing-complete, so it's not exactly an analysis of a program. You could reason about regex, about tokens, then describe them in a way that satisfies the specification, but theorizing like this is exactly opposite to "simple" - it would be so much harder than just learning regex. So stating that testing regex is simple is just bs. The author later confirms he is a bullshitter by his follow-up...

Regexes are easy to test. Bad developers do bad regexes, regardless of whether they used AI.

Etherlord87 2y ago

How do you test a regex to be 100% sure it's valid? I don't think it's possible.

fkyoureadthedoc 2y ago
True for most things I think
eutropia 2y ago
If it's using classical regex, without backtracking or other extensions, a regular expression is isomorphic to a state machine. You can enumerate combinations doing something like this: https://stackoverflow.com/a/1248566 https://stackoverflow.com/a/1248566 kids these days and their lack of exposure to finite automata
- Etherlord87 2y ago
  - Vehicle steering is easy to test. - How so? I don't think it's possible to test for all cases... - Well, it's easy, assuming a car on a non-branching track, moving with a constant speed and without any realistic external influences on it, you can simply calculate the distance traveled using the formula s = v/t. Ah, I wish I'd stop running into fools not knowing Newton's first law of motion... - ??? Are you well?
  - loamaa 2y ago
    I understand you want to refute/diminish the parent comment on finite automata, but I think you are providing a straw man argument. The parent comment does provide an interesting, factual statement. I don't believe finite state automata are at all close in complexity to real-world self-driving car systems (or even a portion thereof). Your closing statement is also dismissive and unconstructive. I believe finite state modeling is used at NASA, A google search brings up a few references (that I'm probably not qualified to speak to), and I also remember hearing/reading a lecture on how they use them to make completely verifiable programs but can't find the exact one at the moment.
    - Etherlord87 2y ago
      I wasn't making a strawman, I was making a parody of his strawman. I thought it's obvious, since I was making an analogy, and it was an analogy to his argument.
  - eutropia 2y ago
    I should have been more clear perhaps: many regexes are capable of being verified with 100% certainty: https://en.m.wikipedia.org/wiki/Thompson%27s_construction https://en.m.wikipedia.org/wiki/Thompson%27s_construction But not all regexes (eg, those using PCRE extensions afaik) are amenable to such a treatment. Those you just tend to hope they work.
spurgu 2y ago
Aren't you asking how to create software without bugs?
- Etherlord87 2y ago
  Well regex isn't Turing-complete, so it's not exactly an analysis of a program. You could reason about regex, about tokens, then describe them in a way that satisfies the specification, but theorizing like this is exactly opposite to "simple" - it would be so much harder than just learning regex. So stating that testing regex is simple is just bs. The author later confirms he is a bullshitter by his follow-up...