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

Hi David,

sorry I’m having trouble replying in a concise and readable manner.

On 08/08/2026 13:50, David Kastrup wrote:
> One thing to note is people_hate_ having to write
>
> xxx = \book { ... }
> yyy = #(define-scheme-function () () #{ \book { ... } #})
> \book { \xxx }
> \book { \yyy }
>
> instead of
>
> xxx = \book { ... }
> yyy = #(define-scheme-function () () #{ \book { ... } #})
> \xxx
> \yyy

Yes, it’s unexpected behaviour without deep knowledge of the internals 
that almost noone has. It would be great to be able to do the former, 
and if that requires to disallow nesting \book then I think we should do 
that.

> but LilyPond does need to know whether to create two separate files or
> not.  And currently the Scheme structures created by \book and \bookpart
> cannot really be told apart.  The results of
>
> xxx = \book { ... }
>
> and
>
> xxx = \bookpart { ... }
>
> cannot reliably be told apart.  And I am trying to figure out whether to
> change that, and how hardboiled the difference should be.

IMO: yes, the difference should be entirely hardboiled.

Best, Simon