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Re: C++ coding style inconsistencies
- From: Martin Liška <mliska at suse dot cz>
- To: gcc at gcc dot gnu dot org
- Date: Tue, 14 Jul 2015 16:31:16 +0200
- Subject: Re: C++ coding style inconsistencies
- Authentication-results: sourceware.org; auth=none
- References: <87vbeblk0y dot fsf at googlemail dot com>
On 06/25/2015 08:28 PM, Richard Sandiford wrote:
> Sorry in advance for inviting a bikeshed discussion, but while making
> the hashing changes that I just committed, I noticed that the C++ification
> has been done in a variety of different styles. I ended up having to follow
> the "do what the surrounding code does" principle that some code bases have,
> but to me that's always seemed like an admission of failure. One of the
> strengths of the GCC code base was always that it was written in a very
> consistent style. Regardless of what you think of that style (I personally
> like it, but I know others don't at all), it was always easy to work on
> a new area of the compiler without having to learn how the surrounding code
> preferred to format things. It would be a shame if we lost that in the
> rush to make everything "more C++".
> The three main inconsistencies I saw were:
> (1) Should inline member functions be implemented inside the class or outside
> the class? If inside, should they be formatted like this:
> foo (args...)
> or like this:
> foo (args...)
> (both have been used).
> The coding standard is pretty clear about this one:
> Define all members outside the class definition. That is, there
> are no function bodies or member initializers inside the class
> But in-class definitions have become very common. Do we want
> to revisit this? Or do we just need more awareness of what the
> rule is supposed to be?
> [Personally I like the rule. The danger with in-class definitions
> is that it becomes very hard to see the interface at a glance.
> It obviously makes things more verbose though.]
> (2) Is there supposed to be a space before a template parameter list?
> I.e. is it:
> foo <bar>
> ? Both are widely used.
> The current coding conventions don't say explicitly, but all the
> examples use the second style. It's also more in keeping with
> convention for function parameters. On the other hand, it could
> be argued that the space in:
> foo <bar, frob>::thing
> makes the binding confusing and looks silly compared to:
> foo<bar, frob>::thing
> But there again, the second one might look like two unrelated
> blobs at first glance.
> (3) Do we allow non-const references to be passed and returned by
> non-operator functions? Some review comments have pushed back
> on that, but some uses have crept in.
> [IMO non-const references are too easy to misread as normal
> In all three cases, whether the answer is A or B is less important
> than whether the answer is the same across the code base.
> If this message does generate any discussion, I'm happy to write up
> the result in the coding conventions and try to make the code base
> consistent with it.
I've got one related question about a class methods. Is there any rule that says
comments related to a function method should be just in declaration or both declaration
and definition? I would welcome to write comments just once :)