[box-tree-api] comments on Box Tree API

Here are some comments on
https://drafts.css-houdini.org/box-tree-api/ as of
revision https://hg.css-houdini.org/drafts/rev/94804d3e9678 :

As with all houdini drafts, the draft should probably suggest where
to send feedback on the document (probably public-houdini?).

Section 2: Boxes and Fragments
==============================

Example 1 seems both a bit hard to follow and missing a number of
fragments:

 * It doesn't mention the fragments of the anonymous inline box
   wrapping all of the contents of the p.  (I thought we agreed to
   change to that model of a single anonymous inline wrapping all
   the contents of the block from the alternative in CSS2 section
   9.2.2.1, although I'm not sure.  Even if we didn't, there are
   missing anonymous inline boxes.)

 * It mentions the fragments of the i element below the list, but
   they should be in the list.

Section 3: API
==============

Should there be a property to access computed style?  Or at least
a property for some notion of type?

Should there be a property to access whether the box is the primary
box for its element (i.e., the one whose computed style matches the
element) or whether it is an anonymous box?  (Perhaps this might
distinguish between different types of anonymous boxes?)

Should there be a property for baseline position(s)?

Beyond that, it's hard to comment on this section without any prose
defining what things are.

-David

-- 
𝄞   L. David Baron                         http://dbaron.org/   𝄂
𝄢   Mozilla                          https://www.mozilla.org/   𝄂
             Before I built a wall I'd ask to know
             What I was walling in or walling out,
             And to whom I was like to give offense.
               - Robert Frost, Mending Wall (1914)