Hello again, Dmitry, and sorry for the late response.

On Fri, Mar 11, 2016 at 2:25 AM, Dmitry Gutov <dgutov@yandex.ru> wrote:
> I see. Is there anything in particular this approach is buying us? 
> Any properties that company-css doesn't support now, and would be 
> suboptimal using its current approach?

Yes, it allows us to stay close to the CSS spec, which is my view is
very valuable when maintaining these lists.

Here is a concrete example: the value class `image' is defined as
follows in the CSS Image Values spec [1]:

  <image> = <url> | <image-list> | <element-reference> | <gradient>

Which translates naturally to:

  ("image" uri image-list element-reference gradient)

It is not a CSS property, so it should go into the value class alist. It
is referenced by the `border-image-source' property as well as the
`bg-image' value class (which in turn is referenced by the
`background-image' property and `bg-layer' value class).

My point is that even though it would be possible to eliminate the need
for this value class by expanding it where it is referenced, I think
that by keeping it, it'll be much easier to make updates to it when the
CSS spec changes. I think it is worth the added complexity.

-- Simen


[1] https://www.w3.org/TR/css3-images/