First of all, I agree with David Kastrup that this is a situation where a deep fix is in order so that simultaneous ties may be tweaked directly.
Your example is working as expected :)
Glad to hear it!
To make it (more) usable, I think, we need wrapper functions, to avoid twiggling with endless listoflistoflistofnumberpairs ;-)
+1
In my short test, I thought of having tie-configuration and shape combined, so that one can set the direction of the ties, before shaping them. The downside is, that using this also needs the staff-positions to be set - so I doubt, this is useful:
This is a useful combination, and setting staff-positions really isn't all _that_ inconvenient since you can include a "non-entry" for default ties. I'm delighted to see that overrides of the two work together! It's nice to be able to group both functionalities into one command.
One question I have here with your formulation concerns the way you've expanded the overrides. Why not use #{ . . . }# syntax here? The only drawback I see is that dollar-signs would be needed with 2.14. I don't see any issues in 2.15.40 with the replacement I've done below:
--snip--
confShapeTieColumn =
#(define-music-function (parser location conf all-offsets)(list? list?)
(let ((alb-func (lambda (grob)
(let ((ties (ly:grob-array->list (ly:grob-object grob 'ties))))
(for-each
(lambda (tie offsets-for-broken-pair)
(let* ((orig (ly:grob-original tie))
(siblings (ly:spanner-broken-into orig)))
(for-each
(lambda (piece offsets-for-piece)
(if (pair? offsets-for-piece)
(set! (ly:grob-property piece 'control-points)
(map
(lambda (x y) (coord-translate x y))
(ly:tie::calc-control-points piece)
offsets-for-piece))
))
(if (null? siblings)
(list orig)
siblings)
offsets-for-broken-pair)))
ties all-offsets)))
))
#{
\once \override TieColumn #'tie-configuration = #conf
\once \override TieColumn #'after-line-breaking = #alb-func
#}))
To be complete, you would need to extend this so that the 'tie-configuration override applies to tie columns across a line break as well. Of course you could easily modify what you have above.
In the attached file, I've approached the problem in a different way. Rather than combining the two overrides as you do, I use two separate overrides. This enables me to override 'tie-configuration with a music function which I made to modify broken spanners in a generalized way. (If you want to see more examples of usage of \alterBroken I can attach a file demonstrating it.) My example isn't the greatest, since I didn't use 'tie-configuration to change any directions--meaning that it's simple to do it all with \shapeTieColumn--but you get the idea.
[BTW, I love how it's now possible to put \once before a music function!]
For completeness I created drafts for RepeatTieColumns and LaissezVibrerTieColumns. Note that after-line-breaking is reasonably not called, so I used before-line-breaking here:
Nice! Thank you for doing this!
Best,
David
shape-tie-columns.ly