referencable appendix

appendix.ly

@@ -0,0 +1,44 @@
+appendix =
+#(define-void-function (parser location title) (markup?)
+  (define (appendix-item->markup layout props appendix-item)
+    (interpret-markup layout props
+      (markup
+          #:override (cons 'appendixItem:heading (assoc-ref appendix-item "heading"))
+          #:override (cons 'appendixItem:text (assoc-ref appendix-item "text"))
+          (ly:output-def-lookup layout 'appendixItemMarkup))))
+  (ly:book-add-bookpart! (ly:parser-lookup '$current-book)
+  #{
+    \bookpart {
+      \markup { #title }
+      #(for-each
+          (lambda (item)
+            (add-score (ly:make-page-label-marker (string->symbol (car item))))
+            (add-text
+              (make-on-the-fly-markup
+                (lambda (layout props arg) (appendix-item->markup layout props (cdr item)))
+                (make-null-markup)))
+          )
+        (reverse APPENDIX_DATA))
+    }
+  #}))
+
+#(define-markup-command (appendix-ref layout props label) (symbol?)
+  "call page-ref to appendix-item"
+  (interpret-markup layout props
+    (markup #:with-link label
+      #:override (cons 'appendixPage (make-page-ref-markup label "XXX" "?"))
+      (ly:output-def-lookup layout 'appendixReferenceMarkup))))
+
+\paper {
+  appendixItemMarkup = \markup {
+    \left-column {
+      \line { \large \bold \fromproperty #'appendixItem:heading }
+      \vspace #0.2
+      \sans \wordwrap-field #'appendixItem:text
+      \vspace #0.7
+    }
+  }
+  appendixReferenceMarkup = \markup {
+    \fromproperty #'appendixPage
+  }
+}