Recommend single indent, not double indent

[hadley]

Fixes #215

Does this correctly capture what you said in the discussion?

[lionel-]

That might be one of the few formatting settings we would implement in Ark for legacy formatting: an option between function-style if it fits (legacy), or single-indent style everywhere ("modern"). Another very similar option would be call-indent style versus single-indent style for function calls, the former matching the RStudio default setting and the latter matching the tidyverse style.

But if we're bold enough, I now think the default / enforced style should be single-indent style to match JS/TS and Rust styling.

[DavisVaughan]

Yea so the "legacy" formatter option logic would be:

• Legacy
  • If it fits, don't break the arguments over multiple lines at all, else
  • If it fits, use function-style line breaks, else
  • Fall back to single-indent line breaks
• Modern
  • If it fits, don't break the arguments over multiple lines at all, else
  • Fall back to single-indent line breaks

I think that Modern (or whatever we call it) would probably result in less code diffs in the long term, at the cost of one big set of upfront diffs as it changes existing function-style -> single-indent style everywhere. I think I'll probably end up preferring this.

Maybe the style guide should just not set a preference between these two styles right now? We can add a preference back in as we feel out the formatter.

[DavisVaughan]

Yea so the "legacy" formatter option logic would be:

• Legacy
  • If it fits, don't break the arguments over multiple lines at all, else
  • If it fits, use function-style line breaks, else
  • Fall back to single-indent line breaks
• Modern
  • If it fits, don't break the arguments over multiple lines at all, else
  • Fall back to single-indent line breaks

I think that Modern (or whatever we call it) would probably result in less code diffs in the long term, at the cost of one big set of upfront diffs as it changes existing function-style -> single-indent style everywhere. I think I'll probably end up preferring this.

Maybe the style guide should just not set a preference between these two styles right now? We can add a preference back in as we feel out the formatter.

[hadley]

It's great that you prefer the single-indent style now that I've finally shifted to liking the function indent style.

[hadley]

It's worth another look now. I also added some advice on S7.

[MichaelChirico]

FWIW we use the term hanging_indent_style in {lintr}:

https://lintr.r-lib.org/reference/indentation_linter.html

[hadley]

Oh yeah I like that better.

[DavisVaughan]

Suggested change

	There are two options if the function name and definition can't fit on a single line. In both cases, each argument goes on its own; the difference is how deep you indent it and where you put `)` and `{`:
	There are two options if the function name and definition can't fit on a single line. In both cases, each argument goes on its own line; the difference is how deep you indent it and where you put `)` and `{`:

[DavisVaughan]

Did you mean to add # Bad? It's currently just another option right? (Same with # Good above)?

i.e. while i feel like we are starting to prefer single-indent, im not sure we are all in on it enough for the style guide to recommend that function-indent is # Bad

[hadley]

Oops, no I meant to write good.