Re: What should the relation between \book / \bookpart be?

On 08/08/2026 19:45, David Kastrup wrote:
> Simon Albrecht <[email protected]> writes:
>
>>> What is wrong with a \bookpart?
>> It causes a page break,
> That is correct.  Maybe some way of being able to merge several
> bookparts into one might make sense.

I also had the thought of providing Scheme function(s) like (name not 
scrutinised) \squashIntoOneBookpart #'identifier or similar.

>> and I understood your goal was to allow for the greatest possible
>> flexibility in reusing segments of a project inside/outside of \book
>> and \bookpart. That was me reading between the lines, which I felt to
>> be necessary.
> Well, the idea was to avoid roadblocks that are hard to understand.
> "Why doesn't this work" should have an answer people can get behind.
> I just have a bad imagination about "people".

Would it be hard to give a clear error message when \book{} blocks are 
nested for example?

>>> If you want to think of things as mere text, you can use include, but
>>> then they _are_ mere text without inherent structure, and depending on
>>> the syntactic context they are included in, the structure may become
>>> different or incoherent.
>>>
>>> There is a reason text-based macros are a nightmare.  You cannot use
>>> them as black box.  You cannot rely on them being interpreted in a
>>> particular manner.
>> I don’t understand. Are you arguing against using \include to
>> modularise a project? Of course using it always requires smart
>> handling of what’s inside and outside any \includes.
> That is the point.  You need to look inside of the includes.
> "Modularisation" means somebody tells you "you can include this file and
> it will do this and that" without needing to look inside.  And basically
> being able to write
>
> \bookpart { \include "someone else's LilyPond source file" }
>
> without having to dig into what is in that file would be nice as an
> ideal.  OF course it will not always work, but one can muse about just
> what complications would make sense to people, and which will not
> exactly be met with enthusiasm.
>