Re: my display function

[Mattes]

Am Samstag, 24. Januar 2015 18:18 CET, "address@hidden" <address@hidden> 
schrieb:

> I want to create my own display function that combines several commands
> into one function.
>
> I have tried this
>
> \version "2.19.15"
>
> #(define bar #f)
> #(define tmp #f)
>
> meDisplay =
> #(define-void-function (parser location message value)
>     (markup? variable?)
>     (display message)
>     (display " : ")
>     (display value)
>     (newline)
>     )
>
> foo =
> #(define-void-function (parser location mus)
>     (ly:music?)
>       (set! tmp (cons #{ b #} #{ cis #}))
>       (meDisplay "tmp" tmp)
>       (newline)
>       (set! bar (acons 1 tmp bar))
>       (display bar)
>       (newline)
>       (set! tmp (cons #{ cis #} #{ b #}))
>       (display tmp)
>       (newline)
>       (set! bar (acons 2 tmp bar))
>       (display bar)
>       (newline)
>       mus
> )
>
> {
>    \foo c'
> }
>
> But I get this error:
> Parsing...c:/users/ame/appdata/local/temp/frescobaldi-a77ofr/tmpe2f6wv/document.ly:19:6:
> In expression (meTrace "tmp" tmp):
> c:/users/ame/appdata/local/temp/frescobaldi-a77ofr/tmpe2f6wv/document.ly:19:6:
> Wrong type to apply: #<Music function #<procedure #f (parser location
> message value)>>
> Exited with return code 1.
>
> I'm probably doing a simple error(?) Like having the wrong type of
> define-???-function.

Yes, you declare meDisplay as taking four arguments but call it with two.
Why don't you define it as a simple scheme function?

#(define (meDisplay message value)
    (display message)
    (display " : ")
    (display value)
    (newline))

Why do you declare foo as a void function? After all, it _does_ return music, 
doesn't it?

foo =
#(define-music-function (parser location mus)
    (ly:music?)
      (set! tmp (cons #{ b #} #{ cis #}))
      (meDisplay "tmp" tmp)
      (newline)
      (set! bar (acons 1 tmp bar))
      (display bar)
      (newline)
      (set! tmp (cons #{ cis #} #{ b #}))
      (display tmp)
      (newline)
      (set! bar (acons 2 tmp bar))
      (display bar)
      (newline)
      mus)

> I have tried a couple of different type of
> functions but ...

If you do it like above everything should work.

 HTH Ralf Mattes

> // Anders
> --
> English isn't my first language.
> So any error or strangeness is due to the translation.
> Please correct my English so that I may become better.
>
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