Re: scheme function returning two scores

[David Kastrup]

Gianmaria Lari <address@hidden> writes:

> On 25 February 2018 at 13:15, David Kastrup <address@hidden> wrote:
>
>> Gianmaria Lari <address@hidden> writes:
>>
>> > Because lilypond "doesn't expect" to return more than one score I tried
>> to
>> > put the call to my function returning the score inside a \book. But this
>> > also does not work and I get this error:
>> >
>> > This is my code:
>> >
>> > \version "2.19.81"
>> > myScore = #(define-scheme-function (music) (ly:music?) #{
>> >     \score { $music \layout{} }
>> >     \score { \unfoldRepeats $music \midi{}}
>> >   }
>> > #})
>>
>> Where is the book you are purporting to return?
>>
>
> First thing: I made another mistake in the code I copied. This is the code
> I wanted to send:
>
> \version "2.19.81"
>
> myScore = #(define-scheme-function (music) (ly:music?) #{
>     \score { $music \layout{} }
>     \score { \unfoldRepeats $music \midi{}}
> #} )
>
> \book {
>  \myScore {\repeat percent 2 {c' d' e' f'}}
>  \myScore {\repeat percent 2 {g c' c' c'}}
> }
>
>
> Second thing: No, I didn't return a book, I return scores inside a
> book.

You cannot return "scores" since "scores" is no type.  You can return a
list of scores (which you would then need to further process), or you
can return a book or a bookpart containing scores, or you can return a
single score.

> The reason is that I don't know how many call to myscore I will need so I
> thought that I have to put it "externally". I don't know if I'm clear.
>
> BUT I also tried to do this:
>
> \version "2.19.81"
>
> myScore = #(define-scheme-function (music) (ly:music?) #{
>   \book {
>     \score { $music \layout{} }
>     \score { \unfoldRepeats $music \midi{}}
>   } #} )
>
> \myScore {\repeat percent 2 {c' d' e' f'}}
> \myScore {\repeat percent 2 {g c' c' c'}}
>
>
> This would create multiple book inside a single file. It looked to me
> that it was not the way to go.

How about creating multiple bookparts?

-- 
David Kastrup