Change default args forStyle/SingleLineBlockParams

[jessieay]

Why:

• This cop enforces block args of a and e by default
• This suggestion causes an "Uncommunicative Variable Name" error from
  Reek
• Source: https://github.com/troessner/reek/blob/master/docs/Uncommunicative-Variable-Name.md
• I tend to agree with Reek on this one. I like expressive variables.
• New default arg names: acc and elem per bbatsov#3601 (comment)

[bbatsov]

I tend to agree with you on this one. But I do feel that a better solution would be to simply make the names configurable (and by default to change them to something like acc and elem maybe). The idea of the rule the cop enforces was that using common short names in short blocks keeps them understandable while preserving horizontal space. We can definitely do better, though.

[bbatsov]

And after I said this I saw the cop is already configurable and one can change the defaults.

[jessieay]

@bbatsov Thanks for taking a look.

The reason I think this cop should not be enabled by default is that I find it unexpected for a style library to dictate variable names . Adding naming guidelines is more common, but actually saying "this variable should be a" rarely makes sense, in my opinion.

If you think we should continue to make this cop enabled by default, what do you think about changing the default args from a and e to accumulator and element so that Rubocop's default config is compatible with Reek?

[bbatsov]

If you think we should continue to make this cop enabled by default, what do you think about changing the default args from a and e to accumulator and element so that Rubocop's default config is compatible with Reek?

I'm fine with changing the defaults, but given the line length constraint I'd say "acc" and "elem" might be better names - still understandable and not that long.

Btw, there's a reason why RuboCop doesn't implement this particular check - it's really hard to figure out of something is a bad name - if you're dealing with points x and y are perfectly reasonable even though they are single character. That said, maybe we should add such a cop and see what feedback we'd get from our users.

[jessieay]

Ok @bbatsov thanks for the feedback -- updated per your suggestion.

I think it would be better not to have requirements for variable names at all, but I think this is a good incremental improvement.

[bbatsov]

The building is failing, because now there are offenses in RuboCop's own code.

[jessieay]

@bbatsov thanks for letting me know! fixed