Hello again,
On 30/07/2020 18:22, Niols wrote:
On 29/07/2020 17:28, Jean-Julien Fleck wrote:
Le mer. 29 juil. 2020 à 15:44, Niols <ni...@niols.fr
<mailto:ni...@niols.fr>> a écrit :
> What do you want to achieve?
This is actually follow-up research from my side after a previous
e-mail
to this list. I would like to print bar numbers that are "repeat
aware",
that is such that if bars 9 to 12 repeat twice, then the bar
numbers go
1, 2, …, 9, …, 12, 17, 18, etc.
with a jump after 12 that corresponds to the bars 13 to 16 that are
actually 9 to 12. Even better, I would like to print the two bar
numbers
for these bars (9/13, 10/14, etc.)
Perhaps this snippet could be of some use for you:
http://lsr.di.unimi.it/LSR/Item?id=1080
I have been playing with this solution and I find it very satisfactory
for my use. I do not understand yet all the intrinsics (in particular
with respect to the context-spec-music and the make-apply-context
functions), but I understand roughly how it works.
There is just one thing that I would want to "improve" (that is, for my
use): the solution needs to map on all the music in order to find all
the VoltaRepeatedMusic and override their callbacks to a newly defined
one. This is achieved by providing a function "unfoldBarNumbers" that
can be applied to any music and that does it.
I would however be interested to have that for all the music in my file,
without having to call that function. The different ideas that pop into
my mind in such a situation are the following:
1. Maybe I could override the "\repeat" function so that it does the
same thing as by default but, when it is a "volta" repeat, it also
attaches the new callback to the created music. I believe I see how to
achieve that, except I seem unsuccessful in overriding the default
definition of "\repeat". Even if I do something like:
#(define (repeat type num body alts)
(display "\nrepeat\n"))
{ b4 \repeat volta 2 { b b } b }
it behaves as if I had not put the #(define ...) statement. I have
played around this idea for a while without success. I have tried to see
if "\repeat" had a special treatment (which it does, at least in the
lexing/parsing), but I haven't been able to figure this out.
I have not managed to override the "\repeat" music function. I suspect
there is something I do not understand in the order in which things are
executed in LilyPond.
I have however found a solution based on overriding "make-music". I
replace "make-music" by a wrapper around it that adds the callback from
the snippet to all 'VoltaRepeatedMusic and leaves the rest alone. This
is actually just a few lines:
#(define the-make-music make-music)
#(define (make-music-wrapped name . music-properties)
(let ((music (apply the-make-music (cons name music-properties))))
(if (equal? name 'VoltaRepeatedMusic)
(ly:music-set-property! music 'elements-callback new-volta-set))
music))
#(set! make-music make-music-wrapped)
It might not be the cleanest, but that is all I have, and that seems to
work.
2. Maybe there is a way to define a function that will be ran before
processing on any music? But this I have no idea if this is possible, or
how to do it, and my research has proven ineffective so far.
3. Maybe there is a way to override the "make-volta-set" callback
instead of creating a new one? Such that then, in LilyPond's normal
execution, it uses the new definition and not and old one that then
needs to be replaced?
For 2. and 3., I still have no idea as this is far beyond my
understanding of the internals of LilyPond. I am not really looking into
it though.
Thank you for your help; have a great Summer!
— Niols
