Re: Extract pitch and duration from ly:music

[Joshua Stutter]

I feel I should enter into the discussion here. I had a conversation 
with Paolo on lilypond IRC where he was wishing to accomplish something 
along the lines of:

fun = #(define-music-function (parser location note dur) (ly:pitch? 
ly:duration?)
#{ $note$dur #})

and create notes from pitches and durations within #{ #}. I explained 
that, to the best of my knowledge, this is not possible and new notes 
must be constructed within Scheme and cannot be concatenated like this.

Joshua.


On 21/02/18 14:29, David Kastrup wrote:
> Paolo Prete <address@hidden> writes:
>
> > Hello,
> > is it possible to extract pitch and duration, inside a function, from
> > a ly:music (a simple note) parameter?
> > I would like to obtain something like:
> > func = #(define-music-function (parser location note dur)
> > (ly:music) #{ ....  $mypitch $myduration .....  #}  )
> > ... But I don't understand if is there a way to obtain $mipitch and $myduration
> > I know that I can extract them with scheme:
> > ((mypitch (ly:music-property note 'pitch '()))    (myduration
> > (ly:music-property note 'duration '())))
> >
> > But I see that it is not possible to use $mypitch and $myduration in
> > the #{ ... #}  scope.
> Can you tell us what makes you see that?