lotabout/fuzzy-matcher

Is there a particular reason why the fuzzing methods return an `Option`?

mainrs opened this issue · 5 comments

mainrs commented

It seems quite unintuitive. I am not familiar with fuzzing internals but from a user perspective, it makes more sense to me that the methods would always return a score. A score of 0 would just mean that the two terms do not match at all.

bausano commented

Looking at the tests it is a bit surprising that these would return None.

mainrs commented

Especially because the other two tests before return Some(0). Maybe it's a relict from the earlier days of the library?

I just think it's easier to work with if it simply returns a usize. And if it's zero, there were no matches. Doesn't matter if the input was ASCII and the pattern was a Chinese character or empty. The current behaviour just doesn't seem to be consistent in all cases.

lotabout commented

@SirWindfield The fuzzy matching algorithm has penalties. The score might be 0 or even negative.

As for these cases:

assert_eq!(Some(0), matcher.fuzzy_match("abcdefaghi", ""));
assert_eq!(None, matcher.fuzzy_match("", "a"));

Note that the semantic of a fuzzy matching is match(choice, pattern), so

  • for match("abcdefaghi", ""), The pattern "" could be "found" in choice, thus returning Some with some score.
  • for match("", "a") The pattern "a" could not be found in choice "", thus returning None
  • 👍2
mainrs commented

thanks for taking your time and explaining the reason behind the return type.