Re: how to write a scheme function to override glissando properties

[Patrick Schmidt]

Am 19.12.2010 um 21:26 schrieb jakob lund:

> I
>
> 2010/12/19 Marc Hohl <address@hidden>:
> > Am 16.12.2010 17:04, schrieb Patrick Schmidt:
> > > [...]
> > > Hi Marc,
> > >
> > > thanks for your solution but I'm still trying to find out what's  
> > > wrong
> > > with the scheme function I posted. I discussed the need for this  
> > > function
> > > with Carl and he gave me some advice:
> > > http://www.mail-archive.com/address@hidden/msg32745.html.
> > >
> > > It might be impossible to find a general set of values for staves  
> > > and tab
> > > staves. If I don't succeed I learned something about writing scheme
> > > functions, at least. Maybe you can spot the mistake in the function?
> >
> > Hm, I don't know what's wrong - I tried something like
> >
> > slide =
> > #(define-music-function (parser location len thick beg end)  
> > (number? number?
> > ly:music? ly:music?)
> >  #{
> >     \once \override Glissando #'minimum-length = $len
> >     \once \override Glissando #'thickness = $thick
> >     \once \override Glissando #'springs-and-rods =
> > #ly:spanner::set-spacing-rods
> >      $beg \glissando $end
> >  #})
> >
> >
> > myMusic = \relative c' {
> >  \slide #10 #5 a4 b4\3
> > }
> >
> > \score {
> > <<
> >  \new Staff {
> >   \new Voice {
> >     \clef "treble_8"
> >     \myMusic
> >   }
> >  }
> >  \new TabStaff {
> >   \new TabVoice {
> >     \myMusic
> >   }
> >  }
> > > >
> > }
> >
> > and that doesn't work either. I don't understand why ...
>
> I think what happens is that the start note, passed to your function,
> is already wrapped up in an object. \glissando is meant for use with a
> single note, rather than with a music object.
>
> You can use scheme to add the `start glissando' property to the  
> object though:
>
> \version "2.13.40"
>
> slide = #(define-music-function (parser location length startnote)
>                                (number? ly:music?)
>                                #{
>  \once\override Voice.Glissando #'minimum-length = $length
>  \once\override Voice.Glissando #'springs-and-rods =
> #ly:spanner::set-spacing-rods
>      #(begin
>            (set! (ly:music-property $startnote 'elements)
>          (cons (make-music (quote GlissandoEvent))
>                (ly:music-property $startnote 'elements)
>                ))
>       (ly:export     $startnote))
> #})
>
> { \slide #7 a'' e'' }
>
> this page contains a similar example
> http://lilypond.org/doc/v2.13/Documentation/extending/adding- 
> articulation-to-notes-_0028example_0029
>
> Jakob
Hi Jakob,

thank you, too for your solution. I did have a look at the section on  
adding articulation to notes in Extending but I think I have a  
different problem. I actually wanted to write a function that calls  
\glissando and overrides its properties more or less for the whole  
score. I'd even prefer to tweak the command \glissando in order to  
get the same output in a Staff and a TabStaff. But I probably didn't  
look in the right place. I just found the definition of \glissando in  
property-init.ly:

glissando = #(make-music 'GlissandoEvent)

But I didn't manage to override its properties. Maybe you know how to  
do it?

Thanks,

patrick
> _______________________________________________
> lilypond-user mailing list
> address@hidden
> http://lists.gnu.org/mailman/listinfo/lilypond-user