> On Jan 26, 2017, at 11:38 AM, Graydon Hoare <[email protected]> wrote:
>
>
>> On Jan 26, 2017, at 2:07 AM, Andrew Trick via swift-dev
>> <[email protected]> wrote:
>>
>> Before I pull in a large PR that "accidentally" reformats a bunch of code, I
>> want to get feedback on how Swift compiler devs plan to use `clang-format`.
>> (BTW, here's the PR https://github.com/apple/swift/pull/6922).
>>
>> During the code review, I ran `git clang-format` as part of being a good
>> citizen. There's only one problem with the tool. It rewraps long boolean
>> expressions, hiding those unsightly operators at the end of lines (after all
>> who wants to see those?).
>>
>> if (some_expression->with_calls() ||
>> another_expression->with(nested_calls()) &&
>> an_even_longer_expression->making_your_eyes->glaze_over())
>>
>> I don't get involved in style wars, but this is not a style change, it's an
>> objective code quality degradation. It's a demonstrably bug-prone thing to
>> do. It's hurt me too many times in the past, and I'm not happy using a
>> formatting tool that injects future bugs and harms code comprehension.
>
> It's funny you'd mention this! I often format code that way, not out of any
> great love of it, but from muscle-memory of living under an old coding
> guideline somewhere in the distant past claiming that the ugliness of
> trailing unfinished-binops draws the eye to them and makes the user pay
> attention. Doug Crockford recommends this style; but of course Don Knuth
> agrees with you. I don't feel strongly about them as such, but I feel ...
> anti-strongly, I guess? Like changing that one thing isn't worth a
> cross-codebase rewrite / merge collision.
I’m not sure who’s recommending what. The above style obscures operators. Does
anyone disagree with that? A lot of code has been written in that way; I think
because developers value aesthetics over clarity, or just don’t think about it.
I care because when something doesn’t stand out, my brain fills in the gaps
with whatever it expects. For me, that leads to a bunch of silly logic errors.
I need to see it this way:
if (some_expression->with_calls()
|| another_expression->with(nested_calls())
&& an_even_longer_expression->making_your_eyes->glaze_over())
The need for parens now stands out. Sorry this isn’t a good example. Nested
expressions would make it much more compelling.
That’s the coding convention we use for Swift code (at least in the stdlib).
The compiler C++ code is just a hodge-podge.
If anyone actually thinks trailing operators are a good idea for our code base,
I won’t argue, but I’ve never heard that argument.
BTW- I’m not interested at all in doing a mass reformatting or forcing a
convention on people. I just don’t want to apply clang-format to every line of
code I touch without knowing what settings to use.
-Andy
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