Validate use of $0 only if it's "simple"

[chriseidhof]

e.g. if it's the first thing that's switched on, or if the closure is really simple (not many tokens).

[jpsim]

👍

[segiddins]

Maybe only allow for single-line closures by default?

[chriseidhof]

Yeah... I often do this pattern:

blablaFunc {
    switch $0 {
        // multiple cases
    }
}

But maybe that's very specific. I guess the important thing is that the $0 is very close to the corresponding opening brace. But having them only in single-line closures is a good first step.

[keith]

I've implemented a rule for this, but it's pretty simple. It just validates that all $0s have a { before them and a } after on the same line. This does mean that it doesn't catch all cases, something like:

foo.map {
     bar.something { $0 }
}

Wouldn't fail, but we feel like most of those cases will be caught by our line length as well. I can submit this upstream if the leniency is alright.

[jpsim]

@keith could you make a PR with your single-line rule? I can't guarantee we'd merge it right away, but it would be a good starting point, at least to stir a conversation.

[keith]

Yep, I'll do that soon.

[keith]

Submitted: #218