Re: names of vertical spacing dimensions

[Mark Polesky]

(David, see the note at the end of this post)

It's not that I want to split hairs; I want to get the new
variable names right the first time.  My apologies to any of
you who are getting tired with this process.  My current
(and hopefully final) proposal is now this:

CURRENT NAME           PROPOSED NAME
------------           -------------
top-system             top-system
top-title              top-markup
between-title          markup-markup
after-title            markup-system
between-system         system-system
before-title           system-markup
bottom-system          system-bottom
between-scores-system  score-system

I've realized one subtlety that should help decide the
remaining debates.  LilyPond has two types of titles,
bookTitleMarkup (title, composer, etc.) and scoreTitleMarkup
(piece and opus).  The elements of bookTitleMarkup will only
display if they are entered in a top-level \header block, so
they cannot be considered part of a "score".  The elements
of scoreTitleMarkup can be entered in a \header block within
a \score block, so they are obviously part of the score.

Here's my rationale for the remaining debates:

* * * * * * * * * *

"between-scores-system-spacing" only applies to this case:
1) from last system of one score to first system of a new
   score, with no intervening top-level markup or
   scoreTitleMarkup.

So calling this variable "score-score-spacing" is misleading
because it does not apply when the new score has a
scoreTitleMarkup.  So now I favor "score-system-spacing".

* * * * * * * * * *

"after-title-spacing" applies to these cases:
1) from top-level markup to first system of a new score.
2) from bookTitleMarkup to first system of a new score
   (when scoreTitleMarkup is absent)
3) within a score, from scoreTitleMarkup to first system.

IMO, within the proposed naming scheme, the only real choice
for after-title-spacing is "markup-system-spacing", since
"markup-score-spacing" is misleading since it does not apply
to scores with a scoreTitleMarkup.

* * * * * * * * * *

"before-title-spacing" applies to these cases:
1) from last system in a score to top-level markup.
2) from last system of one score to scoreTitleMarkup of
   another score.

Within the proposed naming scheme, the 2 choices for
before-title-spacing are:
  system-markup-spacing
  score-markup-spacing

Carl likes "score-markup-spacing" for at least 2 reasons:
1) the upper attachment point is always the end of a score.
2) "system-markup" suggests that it should work within a
   single score, and it doesn't.

I've gone back and forth, but now I'm in favor of
"system-markup-spacing" for the following reasons:
1) it complements "markup-system-spacing" which is easier
   to remember.
2) I disagree with Carl's #2 above since "markup" in a
   variable name only refers to top-level markups (and this
   will be made clear in the documentation).

* * * * * * * * * *

If you're okay with the latest proposal, or if you have
additional arguments... let me know either way.

David, I didn't mean to disregard your last suggestion:
> spacing markup markup = 3cm
> spacing score markup = ...

It's just that it looks like a much bigger change, and
unless someone chimes in with an endorsement and a feasible
implementation strategy, I don't realistically see that
happening before the next release.  But if anyone here can
do this, definitely chime in!

Thanks.
- Mark