Style: no empty newlines at start or end of functions

[tkelman]

These were the few outliers style-wise that looked like this. Mostly from @carlobaldassi.

[amitmurthy]

Can we formalize this with an appropriate addition to https://github.com/JuliaLang/julia/blob/master/CONTRIBUTING.md#general-formatting-guidelines-for-julia-code-contributions

[nalimilan]

+1, we need to make the style guide more detailed.

[tkelman]

Sure, if there's agreement on this point then it's just a matter of how to phrase the guideline.

[amitmurthy]

Since source files are being changed to follow this style, may as well make it a guideline. I am fine with it.

[nalimilan]

See #15439.

[andreasnoack]

I think it can be useful for readability to have a newline in the beginning of a function when the signature is long. Is there a problem with allowing this? E.g. in terms of readability of diffs or something similar? Or is it mainly a matter of taste?

[tkelman]

Consistency. And it wastes space in a way that doesn't clarify anything in my opinion.

[tbreloff]

Personally, I like a space when the function can be broken up cleanly, or if there's a comment on the first line:

function nospace()
  dosomethingshort()
  dosomethingshort()
end

function yesspace()

  # first do this
  this()

  # then that
  that()

  # finally other
  other()

end

[tkelman]

This isn't unique to function definitions, any block opener/closer where you would typically indent the contents, having an empty newline right after the block opener or right before the end is redundant with the indentation and visually decouples the start and end of the block from its contents. It sticks out and doesn't look right to me. I'm all for whitespace between multiple steps, but before-start or after-finished don't count - that's what the function and the end are for.

[amitmurthy]

I concur with Tony on the consistency part, not just in a single file, but with rest of the codebase. Formalizing this as a preferred guideline (and not as a rule) would help. As Andreas points out, exceptions to the guideline could very well be long function signatures which wrap lines, where a newline would help with readability.

[nalimilan]

+1 for consistency as well.

[samoconnor]

Please don't delete blank lines in cases like this where the author has clearly taken some care to use whitespace to delineate functional blocks.

[tkelman]

This makes the code less readable, as it detaches the contents of the function from the surrounding blocks that denote where the function starts and ends. a consistent policy is better than an inconsistent one, even if aesthetic judgements about it differ between contributors.