Re: override-auto-beam-settings

[Jan Nieuwenhuizen]

Ruud van Silfhout writes:

> I already thought that someting like that was the problem, thats the reason
> I posted it on the devel rather that the user list. . So w.r.t this issue
> lily is not backwards compatible.

Indeed, this is but one of many non-backward compatibilities.  Worse,
this is not even forward compatible.  Not much attention was paid to
this, apparently.

> The piece I am working on contains some odd 15 voices or so, so I would
> prefer a solution fitting in the \layout section and more pieces coming up.

> Is there someone who could make this work? If an example project is needed I
> can send one privately.

I see two solutions for 2.4, both of which require messing with
non-documented internals.

One solution is changing the context variable, the other is to make a
(override-auto-beam-settings) that works on score level.

See below.
Jan

%% Copy from scm/auto-beam.scm; because not public there
#(define (override-property-setting context context-prop setting value)
  "Like the C++ code that executes \\override, but without type
checking. "

  (ly:context-set-property! context context-prop
                           (cons (cons setting value)
                                 (ly:context-property context context-prop))))

%% Copy of override-auto-beam-setting, but apply at Score level iso at Voice
#(define-public (score-override-auto-beam-setting setting num den . rest)
  (ly:export
   (context-spec-music
    (make-apply-context (lambda (c)
                          (override-property-setting
                           c 'autoBeamSettings
                           setting (ly:make-moment num den))))
    (if (and (pair? rest) (symbol? (car rest)))
        (car rest)
        'Score))))


\layout {
  \context {
    \Staff
    %% fix 1
    autoBeamSettings = #(cons
                              (cons '(end * * * *) (ly:make-moment 1 2))
                          default-auto-beam-settings)
  }
}
<<
  \new Staff {
    \time 6/4
    a8 a a b b b
    a8 a a b b b
  }
  \new Staff {
    a8 a a b b b
    a8 a a b b b
  }
  %% fix 2
  #(score-override-auto-beam-setting '(end * * * *)  1 2)
>>

-- 
Jan Nieuwenhuizen <address@hidden> | GNU LilyPond - The music typesetter
http://www.xs4all.nl/~jantien       | http://www.lilypond.org