creating a bookpart generating scheme function in lilypond

Question

I am creating a piano book in LilyPond, which I am using for the first time. I am separating each piece into its own \bookpart, and if any of them have multiple movements, then each movement is in a different \score block. I also include table of contents entries for each \bookpart, and if there are multiple movements, one entry for each movement. I would like to create a scheme function that would generate the majority of this layout for me, to avoid copying/pasting this layout every time I add a piece to the book. I found the answer here that shows how to do something similar to what I would like, but with the following differences:

• It needs to allow for multiple scores in the \bookpart
• It needs to add a \tocItem for the \bookpart, and each \score.

After playing around with the answer in the link above, I reached a point where I had these functions:

defaultBookPart = #(define-scheme-function
    (scores toclabel tocentry title composer)
    (ly:score? (symbol-list-or-symbol? '()) markup? string? string? )
    (toplevel-bookpart-handler #{
        \bookpart {
            \header {
                title = $title
                composer = $composer
            }
            \tocItem $toclabel $tocentry
            #scores
        }
    #})
)

defaultScore = #(define-scheme-function
    (righthand lefthand piece opus)
    (ly:music? ly:music? string? string?)
    (toplevel-score-handler #{
        \score {
            \header {
                piece = #piece
                opus = #opus
            }
            \new PianoStaff <<
                \set PianoStaff.connectArpeggios = ##t
                \accidentalStyle "piano"
                \new Staff \relative {
                    #righthand
                }
                \new Staff \relative {
                    \clef "bass"
                    #lefthand
                }
            >>
        }
    #})
)

defaultMovementScore = #(define-scheme-function
    (righthand lefthand toclabel piece opus)
    (ly:music? ly:music? (symbol-list-or-symbol? '()) string? string?)
    (toplevel-score-handler #{
        \score {
            \header {
                piece = $piece
                opus = $opus
            }
            \new PianoStaff <<
                \set PianoStaff.connectArpeggios = ##t
                \accidentalStyle "piano"
                \new Staff \relative {
                    \tocItem $toclabel \markup $piece
                    #righthand
                }
                \new Staff \relative {
                    \clef "bass"
                    #lefthand
                }
            >>
        }
    #})
)

I am getting bad expression type errors when I try to use these, and in addition I see the following problems with this approach:

• The first argument to the defaultBookPart function has the wrong type. I was unable to find in the documentation a score-list type, but it looks like there is a built-in function that takes a similar argument: ly:make-book-part. I was unable to find what the correct type to pass in there would be however.
• I'm not sure that the toclabel arguments have the right type either. I was able to find the type specified above in the toc-init.ly file, but when I try to call my function, it doesn't seem to like the same input as can be used in the tocItem function.

Is there a way to resolve these issues? I am also having a hard time figuring out how to call these, passing the output of the score functions into the bookpart function.

Answer 1

Regarding your first point: You can simply use the predicate list?. Regarding the second point: This should be correct.

But maybe you want to go for a solution with slightly less complexity like this:

#(define (list-or-music? x)
   (or (ly:music? x) (list? x)))

#(define (format-movement-toc opus part-index)
   (format "Movement ~a" (1+ part-index)))

#(define (format-title-toc composer title opus)
   (markup #:line ( #:concat ( composer ":" ) )
                    #:hspace 1
                    title
                    #:hspace 0.4
                    #:normal-text #:italic #:concat ( "(" opus ")" )))

#(define (create-score composer title opus multi-part? part-label rhs lhs)
   (let ((label (if multi-part?
                    (if (number? part-label)
                        (format-movement-toc opus part-label)
                        part-label)
                    "")))
     #{
       \score {
         \header {
           piece = #label
         }
         \new PianoStaff <<
           \set PianoStaff.connectArpeggios = ##t
           \accidentalStyle "piano"
           \new Staff \relative {
             #(if multi-part?
                  (add-toc-item! 'tocItemMarkup label
                                 (list (string->symbol
                                        (format "~a"
                                                (format-title-toc composer title opus)))
                                       (string->symbol (format "~a" label))))
                  (empty-music))
             #rhs
           }
           \new Staff \relative {
             \clef "bass"
             #lhs
           }
        >>
      }
     #}))

createPiece =
#(define-void-function
  (composer title opus movement-labels music-pairs)
  (markup? markup? markup? list? pair?)
  (if (and (list? music-pairs) (null? movement-labels))
      (set! movement-labels (iota (length music-pairs))))
  (if (and (list? music-pairs) (= (length music-pairs) 1))
      (set! music-pairs (car music-pairs)))
  (toplevel-bookpart-handler #{
    \bookpart {
      \header {
        title = #title
        composer = #composer
        opus = #opus
      }
      \tocItem #(string->symbol (format "~a" (format-title-toc composer title opus)))
               #(format-title-toc composer title opus)
      $@(if (list? music-pairs)
            (map (lambda (l p) (create-score composer title opus #t l (car p) (cdr p)))
                 movement-labels
                 music-pairs)
            (list (create-score composer title opus #f 1 (car music-pairs) (cdr music-pairs))))
    }
                             #}))

makeMusicPair =
#(define-scheme-function (m1 m2) (ly:music? ly:music?)
   (cons m1 m2))

\markuplist\table-of-contents

\createPiece "composerA" "titleA" "opusA"
  #'()
  \makeMusicPair
  { c'' d c d }
  { c d e f }

\createPiece "composerB" "titleB" "opusB"
  #'()
  #(list
    (makeMusicPair #{ c' d e f #} #{ c b c d #})
  )

\createPiece "composerC" "titleC" "opusC"
  #'()
  #(list
    (makeMusicPair #{ c' d e f #} #{ c b c d #})
    (makeMusicPair #{ c'' b a g #} #{ e g f e #})
  )

\createPiece "composerD" "titleD" "opusD"
  #'("Allegro" "Andante")
  #(list
    (makeMusicPair #{ c' d e f #} #{ c b c d #})
    (makeMusicPair #{ c'' b a g #} #{ e g f e #})
  )