repair transposition for books

transposition.ly

@@ -1,13 +1,22 @@
-TRANSPOSITION = ##f
+TRANSPOSITION = #(cons #f #f)
 
 transposeGlobal =
 #(define-void-function (from to) (ly:pitch? ly:pitch?)
    (set! TRANSPOSITION (cons from to)))
 
 transposable =
-#(define-music-function (music) (ly:music?)
-  (if TRANSPOSITION
+#(define-music-function (fromto music) (pair? ly:music?)
+  (if (car fromto)
     #{
-      \transpose #(car TRANSPOSITION) #(cdr TRANSPOSITION) #music
+      \transpose #(car fromto) #(cdr fromto) #music
     #}
     music))
+
+% Akkorde in Strophen transponieren
+#(define-markup-list-command (transpose layout props from to markuplist)
+  (markup? markup? markup-list?)
+
+  (define (markup->pitch m)
+    (ly:assoc-get (string->symbol (markup->string m)) pitchnames))
+
+  (interpret-markup-list layout (prepend-alist-chain 'transposition (cons (markup->pitch from) (markup->pitch to)) props) markuplist))