[LLVMdev] RFC: variable names

[Sean Silva]

On Mon, Oct 13, 2014 at 5:09 PM, Jim Grosbach <grosbach at apple.com> wrote:

>
> On Oct 13, 2014, at 4:31 PM, Chandler Carruth <chandlerc at google.com>
> wrote:
>
>
> On Mon, Oct 13, 2014 at 4:14 PM, Chandler Carruth <chandlerc at google.com>
> wrote:
>
>> 1. Initialisms. It's common in Clang code (also in LLVM?) to use
>>> initialisms as variable names. This doesn't really seem to work for names
>>> that start with a lower case letter.
>>>
>>
>> I think wee at least need a good answer to this.
>>
>
> As I really suspect this is the most important point to address, let me
> make an attempt:
>
> Variable names are *either* initialisms, written as all caps, or terms
> written in lower case and separated by underscores. For the purposes of
> variable naming "terms" can include words but also extremely common and
> recognizable abbreviations within LLVM such as "rhs", "lhs", or "gep".
> These types of terms should not be written as initialisms but as words. For
> example, you might write "LE" or "lhs_expr" for the Left-hand Expression,
> but not "LHSE" or "LHS_expr".
>
> While I'm trying to avoid it, this has the advantage of leaving a large
> number of initialisms in the existing code base as "stylish".
>
>
> I'm not really happy with this rule, but it is the least disruptive and
> most consistent I can come up with. I would also be happy encouraging
> people to not use initialisms excessively or if confusing. I think the
> current codebase uses them more than is helpful.
>
>
> This makes sense to me. I think it strikes a good balance between updating
> our conventions to be better and also reflecting common in-practice usage
> patterns.
>

This convention sounds like it would cause people to have to be constantly
asking themselves "is this common enough to be an initialism-as-word or
not?". The thing that started this conversation was someone complaining
about going between codebases that they weren't sure whether to capitalize;
now that person will have to get a feel for the local initialism-as-word's,
which is a much greater burden than just the naming convention.

-- Sean Silva


>
> FWIW, I think that having different naming conventions for data members
> and local variables has become essentially untenable with lambdas and
> capture.
>
>
> Can you elaborate a bit more on this? Maybe an example or two.
>
> I’m very supportive of the general direction of all of this. Glad to see
> the general consensus developing.
>
> -Jim
>
>
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