Re: LSR 507 (ghost voice) broken since 2.15.28

[Eluze]

dak wrote
> David Kastrup <

> dak@

> > writes:
> 
>> David Kastrup <

> dak@

> > writes:
>>
>>> Eluze <

> eluzew@

> > writes:
>>>
>>>> LSR 507 <http://lsr.dsi.unimi.it/LSR/Item?id=507> produces
>>>> erroneous
>>>> code since version 2.15.28:
>>>>
>>>> mus = { c4 d e f |}
>>>>
>>>> \displayLilyMusic \ghostMusic \mus
>>>
>>> That's fallout from issue 2240, Patch: Don't wrap EventChord around
>>> rhythmic events by default.  It won't be the only affected item.
>>>
>>> The basic question is when should we be migrating the LSR to 2.16.
>>>
>>> In this particular case, only the first of several "adjacent" spacers is
>>> retained.  The reason for that apparently is to avoid 
> <c e>
>  getting
>>> turned into what amounts to 
> <s s>
> .  I don't think that this
>>> simple-minded approach is all too likely to lead to sane results without
>>> more effort, even pre-2.15.28.  So my take on this would be to just junk
>>> the music-filter expression.  This is going to lead to constructs
>>> occasionally that one can't actually enter, but which should at least
>>> compile reasonably well.
>>
>> In a nutshell:
>>
>> ghostMusic =
>> #(define-music-function (parser location music) (ly:music? )
>>   (music-map (lambda (x)
>>            (let ((dur (ly:music-property x 'duration)))
>>             (if (ly:duration? dur)
>>              (apply make-music 'SkipEvent
>>               (flatten-alist
>>                (ly:music-mutable-properties x)))
>>              x)))
>>    music))
>>
>>
>> notes = { a2-"hello" b4 r b2 a-"bye" 
> <c e g c' e' g'>
> 1-"oho ;-)" }
>>
>> \ghostMusic \notes
>>
>>
>> This is not going to work out of the box with chord repetitions.
> 
> And here is a version that should work both with 2.14 as well as 2.16
> and be fine with chord repetitions.

thanks, David, this works perfect!

to avoid warnings and errors I have removed a few engravers - in  my case
these were

\layout {
  \context {
    \Voice
    \remove Arpeggio_engraver
    \remove Beam_engraver
    \remove Grace_beam_engraver
    \remove Slur_engraver
    \remove Tie_engraver
    \remove Tuplet_engraver
   …
  and others in other contexts
}}

maybe the snippet should point to this?!

Eluze



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