Enforcing a 80-character line length rule?

[jarodmeng]

Is it possible to enforce a rule to limit code to 80 character per line? styler currently doesn't seem to do that. The closest issue I can find is #118, but it's not clear if that option is available.

[lorenzwalthert]

Thanks for having consulted open issues first. #118 is an edge case as far as indention goes and not quite what you are referring to. The task of splitting lines of code with more than 80 characters is non-trivial as it is not a-priori clear at which position lines should be split. I think this may also not follow a general and abstract rule (as the other styling rules) but is best done manually and decided on a case-to-case basis. Therefore, this feature is currently no supported in styler and will probably no be so in the near future. We suggest to use the packages lintr to detect lines with more than 80 characters and rearrange manually.

Edit: I think we aim to support this in the long run.

[krlmlr]

I'm working on (finally!) releasing utf8, this means we could release styler soon. After this I think we could start thinking about that 80-character rule, because editing code from "wide" to "long" takes quite a lot of time (measured in seconds, but still). I'd like to suggest to do it at the level of function calls and arithmetic expressions first:

• If a single-line function call hits the 80-character boundary, add a line break after the opening paren, and proceed with usual rules.
• If an arithmetic expression is too wide, add line breaks after lowest-prio operators (i.e., the + in 1 * 2 + 3 * 4)

Maybe start with only function calls -- if we add a set of rules after all other rules (because we need to be sure about the width), and then do only reindention of function call arguments?

[jarodmeng]

Thanks for the reply! I agree that it's not easy to implement such a rule. @krlmlr 's suggestion looks good to me.

[lorenzwalthert]

So do you @krlmlr suggest to take the 80 character limit from the (raw) unstyled expression, right?

[krlmlr]

No, that would be after styling, when we know the final width -- we'd just add linebreaks but not change much otherwise.

[lorenzwalthert]

Issues that can't be resolved soonish will be closed and labelled "Status: Postponed".

[lorenzwalthert]

Reference: #65.