Explanation of values about complexity

[joshuaclayton]

@pylipp that's a great question and one that I don't quite know the answer to yet. The algorithm we use is one very quickly hacked together that correlated with what we were seeing generally from rubycritic from one of our moderately large internal Rails codebases (~100kloc).

When I run the tool, I'm doing a numeric sort complexity | sort -n --reverse | head -n 20 to get a sense of where to focus within new codebases. There might be too strong a correlation with file length – and the algorithm can be adjusted if that's the case.

If the score of a file is < 100, it's likely it's going to be easy to grok. Again, this is an approximation tool, and not one that interprets files. I don't expect that to change anytime soon.

I did break apart scoring to use the visitor pattern as a way to encourage other algorithms/approaches be used. I would imagine this could be configurable on a per-file-type basis eventually, or score differently for files that don't "roll back up" like Haskell or Elm versus Ruby or Elixir.

The current algorithm: 7fb66a2#diff-0e83e34ba12421d41f8a2e93ca67eff995ef8511c656b50a56e45fc9167d8abe

The current scoring structure that uses the scoring visitor:

complexity/src/scoring.rs

Lines 14 to 40 in 4112cda

	pub fn score<V: ScoreVisitor>(visitor: &mut V, input: &[usize]) -> f32 {
	let line_length = input.len();
	visitor.visit_line_length(line_length);
	let mut previous_line_whitespace = None;
	for current_whitespace in input {
	match previous_line_whitespace {
	None => {
	visitor.visit_first_line(*current_whitespace);
	}
	Some(previous_whitespace) => {
	if previous_whitespace < *current_whitespace {
	visitor.visit_indent(*current_whitespace);
	} else if previous_whitespace == *current_whitespace {
	visitor.visit_same(*current_whitespace);
	} else {
	visitor.visit_dedent(*current_whitespace);
	}
	}
	}
	previous_line_whitespace = Some(*current_whitespace);
	}
	visitor.score()
	}

The current written-out way to read the current scoring algorithm: 7fb66a2#diff-12b7e19d8f3e5e1cf0dbe75aff102362944bb1cf00c4634b2aec22fe393c16e9R115-R133