Re: Bug with transpose in functions

[Aaron Hill]

On 2019-07-11 11:52 pm, Immanuel Litzroth wrote:
> This seems to do the wrong thing:
>
> >
> \version "2.19.81"
> testme = #(define-music-function
>            (parser location music)
>            (ly:music?)
>            #{
>              \transpose c c' {#music } {#music }
>              #})
> \testme g'
> >
> printing out two g'' instead of a g'' and a g'

Consider using $music or ly:music-deep-copy:

%%%%
\version "2.19.83"
testI = #(define-music-function (music) (ly:music?)
  #{ \transpose c c' $music $music #})
testII = #(define-music-function (music) (ly:music?)
  #{ \transpose c c' #(ly:music-deep-copy music) #music #})
\testI d' \testII e'
%%%%

> Also I found it strange that {#music} is not accepted as an argument 
> with
> the
> following error:
> > tmp.ly:6:16: error: GUILE signaled an error for the expression 
> > beginning
> here
> >            {#
> >              music}
> > Unbound variable: music}
> It seems to parse the closing } as part of the variable name.

Scheme is pretty permissive with what can be part of a symbol, so this 
is one case where whitespace does matter.


-- Aaron Hill