bug#24389: [PATCH] Support completion of classes and IDs in CSS mode

[Stefan Monnier]

>> The definition of those global variables seems to be missing.
>> IIUC they should be in css-mode.el, so their name should start with
>> "css-" I think (tho I agree that it's debatable).
> Hm, is it wrong to let them stay void, and then check whether they're
> bound in each buffer we visit?

What'd be the benefit?  You do want to `defvar' them in order to give
them a doctring (which means that if you want them void you have to do
extra gymnastic), and giving them a good default value means you can
call them without having to check the value beforehand (and that also
means you can use `add-function' on it).

> I ran som benchmarks to assess whether the expensive buffer-hash cache
> is worth it, results follow below.

`buffer-hash` is only a problem in large buffers.  But you can use
buffer-text-modified-tick to get a much quicker test (only important in
large buffers).  And you might not even need to test
buffer-text-modified-tick because you can often just flush the (relevant
part of) the cache(s) from an after-change-functions or from
syntax-propertize or ...

> +      (with-current-buffer buf
> +        (when (boundp extractor)
> +          (funcall (symbol-value extractor)))))

You don't need the boundp test here, AFAICT.


        Stefan