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

[Keith OHara]

On Sun, 05 May 2013 01:20:17 -0700, <address@hidden> wrote:

> Maintaining a "cursor position" in stack-stencil-line and friends means
> that you can't assemble partial lines yourself in a manner blending in.
> That's bad.

Oh. I thought it was good.  If the possibly-backspaced cursor is forgotten when 
\line is finished, then the user doesn't have to remember where the cursor 
ended up.
\markup { A
 \line {reverse turn \hspace#-5 \raise #2 \musicglyph #"scripts.reverseturn" }
 is found in the original manuscript.}

I suppose this comes out the same in your more-recent iterations.  Only 
backspace at the end of a \line has a difference.  Even in that case I would 
rather forget about pending backspaces.  The original fix to the issue suffered 
because a parenthesized item (with repaired refpoint) blended in when we 
assembled partial lines
  parenFlat = \markup {\hspace#-2 ( \flat )}
  \markup {An editorial \parenFlat flat}
It is a little surprising if \parenFlat carries a pending backspace. If the 
markup building \parenFlat implements the backspace, and then tells no-one 
about it, it makes a simpler interface.

It looks very good that you made 'empty' mean (+inf . inf) so that negative 
extents don't count as empty.  But then defining 'half-empty' complicates 
things again, and I have not found a use for it.