Clarification on multiline defs about elixir_style_guide HOT 3 OPEN

Given that the formatter enforces blank lines between multiline defs, the style conventions could be reworded as:

1. Don't separate single-line defs of the same function with blank lines.
2. If you have more than one multiline def of the same function, don't use single-line style at all.

The first rule seems like a sensible style suggestion. The second one I'm unsure about. I can imagine (like you suggest) a recursive function with a series of single-line defs, followed by two multi-line defs, followed by another series of single-line defs, etc. Re-writing them as all as multiline just to follow this style rule wouldn't seem sensible.

Does anyone have strong opinions about the multiple-function-defs rule?

See #39 and #116

from elixir_style_guide.

from elixir_style_guide.

Looking again at the multiple-function-defs rule, it was introduced in #39 in order to close #23, but the stated rationale of "not mixing single-line and multi-line for more than one multi-line def" was accepted without discussion.

I think we can agree on the rule to remove blank lines between single-line defs and add them between multi-line defs:

def some_function(nil), do: {:error, "No Value"}
-
def some_function([]), do: :ok
+
def some_function([first | rest]) do
  some_function(rest)
end

But if we were to add another multi-line def, do we really need to re-write everything to be multi-line? Any small benefit to readability I think is outweighed by the downsides of having to re-write perfectly fine single-line defs, which would complicate the commit diff (and any time you re-write something you could introduce bugs or regressions).

I would propose dropping the multiple-function-defs rule since it seems unnecessarily difficult to understand, use, and maintain the style.

from elixir_style_guide.