Re: calculation in scheme

[Neil Puttock]

On 17 September 2011 14:23, Stefan Thomas
<address@hidden> wrote:
> Dear community,
> I would like to define a variable with sheme and I want to substract the
> number one from this variable.
> I tried it with:
>
>> % the following defines a Slur, lasting a certain number of eigth-notes
>> xaS = #(define-music-function (parser location x) (number?)
>>   #{ % in der folgenden Zeile Lilypondcode eingeben
>>     s1*0 (  \repeat unfold  #(- $x 1)  {s8 } s8)
>> #})
>
> Unfortunately without succes!

This doesn't work since the unfold count argument isn't a scheme
number.  I suggest resetting 'repeat-count inside scheme instead:

\version "2.15.11"

xaS =
#(define-music-function (parser location x) (number?)
   (let ((repeat-music #{ \repeat unfold 1 s8 #}))
     (set! (ly:music-property repeat-music 'repeat-count)
           (1- x))
     (make-sequential-music
      (list #{ s1*0( #} repeat-music #{ s8) #}))))

\new Voice \relative c' {
  << { c8 d e f } \xaS #4 >>
}

Cheers,
Neil