Grand PartCombine Rewrite Project

[Kieren MacMillan]

Hello all,

I've decided this is going to be my pet project during this, my  
"Autumn of Lilypond".
I've started a separate thread here, and would like to get moving on  
the project as soon as possible. [n.b. I am not intending to cross- 
post to -user after this "announcement" email.]

1. Team members. Several people (Wol, etc.) expressed an interest in  
helping; if you are one of these, please re-confirm your interest  
here, for thread completeness. If anyone else wants to help, just  
shout out.

2. Lead(s). I don't mind taking the lead on this if nobody else wants  
that job; however, if anyone *does* want it, I can guarantee you'll  
do better than I, and am happy to defer.

3. Programming. In order to get this done before, say, 2020, we'll  
need at least one lead developer with good Scheme-fu to (1) write  
most of the heavy-lifting code, and/or (2) vet my/our Froggie work.  
In either case, my goal is to have "clean" patches to give to Carl/ 
whomever for final merging, as opposed to banging on his/their door  
with sketchy code.

4. Here's my first, naive attempt at listing the areas where a good  
partcombine must Do The Right Thing:
  — \relative
  — \transpose
  — \times
  — lyrics
  — merging/discarding notes & rests
  — merging/discarding text (e.g., markup)
  — merging/discarding articulations, etc.
  — adding "editorial" texts (e.g., "a2")
  — unlimited number of parts

5. My 30000-foot plan on how to proceed is to:
   — dissect the current implementation to see if anything can be  
saved/rewritten;
   — plan the implementation revision/rewrite; and;
   — do it.

Any thoughts/help would be greatly appreciated.

Best,
Kieren.