RE: Reorganizing the contents of the \paper block

[Carl D. Sorensen]

> No, top-level \paper sets a default for the \book level \paper.
> top-level \layout sets a default for \score level \layout.
> 
> \layout { X }
> \paper { Y }
> 
> mean 
> 
> $defaultlayout = \layout { \$defaultlayout X } $defaultpaper 
> = \layout { \$defaultpaper X }
> 
> independenty of this
> 
>   \book {
>      \score  { 
>         \layout {  
>             %% A
>         }
>      }
>      \paper { 
>        %% B
>      }
>    }
> 
> means
> 
>   \book {
>      \score  { 
>         \layout { \$defaultlayout
>             %% A
>         }
>      }
>      \paper { \$defaultpaper
>        %% B
>      }
>    }
> 
> 
> If at run time, a score-level layout variable, such as 
> ragged-right, is looked up in %A. 
> If it's not found, it is looked
> up in %B. If it's not found in %B, then it is assumed undefined.
> 
> iow. There are 2 orthogonal mechanisms: 
> 
>  - toplevel output-defs set defaults, which are copied 
> implicitly during parsing ( $defaultlayout / $defaultpaper )
> 
>  - the \paper (book level) is parent to \layout (score 
> level), this parent relation is employed during formatting.
> 

Perhaps part of the confusion about the overall structure of LilyPond arises 
from the fact that sometimes (e.g. when identifiers are used), the order of 
statements matter; while at other times (e.g. %B being a place to lookup layout 
variables from %A) the order doesn't matter.  In fact, in the lookup process 
you described above, there is no clue in the file that (i) %B is defined for a 
\book,  (ii) the \score is contained in a \book, and (iii) the \layout of which 
%B is a part is in any sort of scope that includes the \score of which %A is a 
part.

Carl  Sorensen