Re: Issue 3330: redo much of the stencil stacking/spacing/empty-check (issue 8869044)

[k-ohara5a5a]

Shucks.  It gets difficult to space a list of stencils if all you have
to work with are the refpoint and extents of the next stencil, and the
composite of those accumulated so far.

What we would like is :
\line {a b c ... } places the left extent of each markup in the list
against the right extent of the previous markup, plus padding specified
by the property 'word-space.  The result is a markup with extent that
encloses the extents of all the individual markups, and overall
reference point at the reference point of the first markup 'a'.

We just need to keep track of one variable: the right extent of the
most-recently placed markup.  Too bad Scheme doesn't provide a way to
keep a running variable as you walk the list.  I guess that is why
procedural languages are so much better than functional languages.

https://codereview.appspot.com/8869044/