Re: Passing music objects into scheme functions

[Charles Winston]

Here is the function inside chord-name.scm


;; chordmode-to-exceptions
(define-safe-public (chordmode-to-exceptions chord markup)
  "Transform event-chord entered in chord mode to alist
entry in chordSemanticsNameExceptions list
"
  (define (is-semantics-event? x)
    (ly:in-event-class? x 'chord-semantics-event))
  (define (get-semantics chord)
    (let* ((elts (ly:music-property chord 'elements))
           (semantics-event (filter is-semantics-event? elts))
           (semantics-list (ly:event-property semantics-event 
'chord-semantics)))
      semantics-list))
  (list (cons (get-semantics chord) markup)))

And here is my branch which has added chord semantics and new naming 
capabilities based on these semantics: 
https://github.com/charlesrwinston/lilypond_chords/tree/dev/crw_chordsemantics


> On Aug 14, 2017, at 12:46 PM, Charles Winston <address@hidden> wrote:
> 
> Hi developers,
> 
> I’m working on chord semantics and creating a new way to input chord name 
> exceptions. I want the chord exceptions to be an alist whose keys are the 
> chord's semantics list and values are the exception markups. I wrote a 
> function that takes an event chord and a markup as parameters and returns an 
> alist pair with the correct key and value. I’m trying to test my function, 
> and I have this:
> 
> chordVar = \chordmode { c1:m7 }
> 
> markupVar = \markup { “min7” }
> 
> #(chordmode-to-exceptions chordVar markupVar)
> 
> 
> On the last line I get the following error:
> 
> Wrong type argument in position 1 (expecting Prob): ()
> 
> 
> When i do #(display chordVar) and #(display markupVar) their structures print 
> what I expect. Could someone help me understand why this error could be 
> happening?
> 
> Thanks,
> Charles
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