Re: Setting paper for bookpart

[Thomas Morley]

2017-08-02 22:38 GMT+02:00 David Kastrup <address@hidden>:
> Thomas Morley <address@hidden> writes:
>
>> 2017-08-02 18:27 GMT+02:00 David Kastrup <address@hidden>:
>>> Thomas Morley <address@hidden> writes:
>>>
>>>> 2017-08-02 15:46 GMT+02:00 David Kastrup <address@hidden>:
>>>>
>>>>> #(ly:output-def-set-variable! (ly:book-paper bkII) 'ragged-right #f)
>>>>
>>>> This works fine, but only if the bookpart already has \paper
>>>
>>> So use the LilyPond syntax variant instead?
>>>
>>> What are you currently after?  Getting some task done or working out
>>> where LilyPond's Scheme interfaces are having holes and getting them
>>> filled?
>>>
>>> Of course approaches differ then.
>>
>> This thread was triggered by a request in the german forum
>> https://lilypondforum.de/index.php/topic,105.msg686.html
>> While I think there is a working sollution over there, I now try to
>> explore whether LilyPond could be improved with regard to this topic.
>>
>> I can fill an empty bookpart with a header using ly:book-set-header!
>> I can fill an empty bookpart with scores using ly:book-add-score!
>> But obviously there's no possibility to get a paper into an empty
>> bookpart. Otherwise the answer would have been dropped hours ago.
>>
>> What's needed to have/get/code such a function?
>
> I think that part of the problem is that looking at the functions in
>
> lily/book-scheme.cc
>
> it seems like bookparts were never intended to have paper blocks.  Now
> after actually checking it would appear that at least several bookparts
> cannot appear on the same page: so at least the paper dimensions likely
> don't clash.
>
> So what is supposed to be the actual difference between bookparts and
> books?
>
> I actually don't know how to tell, and it shows by the parser not
> knowing how to know that
>
> \xxx
>
> is not a book when xxx has been defined as \bookpart { \paper {...} ...}.
>
> I really don't have an idea what the distinction is supposed to be about.
>
> --
> David Kastrup

Thanks for your findings and thoughts.

At least one distinction can be seen here:

foo = \book { }
#(format #t "paper present? ~a" (ly:book-paper foo))

bar = \bookpart { }
#(format #t "paper present? ~a" (ly:book-paper bar))

The latter displays #f, which is inline with what you said above:
"bookparts were never intended to have paper blocks"
Otoh, paper in bookpart _is_ supported, at least nowadays ...

Cheers,
  Harm