X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=scm%2Fpredefined-fretboards.scm;h=5f4d7005cd518af052ee8d7bee690ce5d5529be7;hb=HEAD;hp=ff0200729d230881949b1e18aeb8a3a86b5cf985;hpb=1528c75809ebc59d93018dbf59559436f75f082b;p=lilypond.git

diff --git a/scm/predefined-fretboards.scm b/scm/predefined-fretboards.scm
index ff0200729d..5f4d7005cd 100644
--- a/scm/predefined-fretboards.scm
+++ b/scm/predefined-fretboards.scm
@@ -1,6 +1,6 @@
 ;;;; This file is part of LilyPond, the GNU music typesetter.
 ;;;;
-;;;; Copyright (C) 2008--2011 Carl D. Sorensen <c_sorensen@byu.edu>
+;;;; Copyright (C) 2008--2015 Carl D. Sorensen <c_sorensen@byu.edu>
 ;;;;
 ;;;; LilyPond is free software: you can redistribute it and/or modify
 ;;;; it under the terms of the GNU General Public License as published by
@@ -19,40 +19,36 @@
 (define-public (parse-terse-string terse-definition)
   "Parse a @code{fret-diagram-terse} definition string @var{terse-definition}
 and return a marking list, which can be used with a fretboard grob."
-   (cdr (fret-parse-terse-definition-string (list '()) terse-definition)))
+  (cdr (fret-parse-terse-definition-string (list '()) terse-definition)))
 
 (define-public (get-chord-shape shape-code tuning base-chord-shapes)
   "Return the chord shape associated with @var{shape-code} and
 @var{tuning} in the hash-table @var{base-chord-shapes}."
   (let ((hash-handle (hash-get-handle base-chord-shapes
-                                       (cons shape-code tuning))))
-     (if hash-handle
-         (cdr hash-handle)
-         '())))
+                                      (cons shape-code tuning))))
+    (if hash-handle
+        (cdr hash-handle)
+        '())))
 
 (define-public (offset-fret fret-offset diagram-definition)
   "Add @var{fret-offset} to each fret indication in
 @var{diagram-definition} and return the resulting verbose
 @code{fret-diagram-definition}."
-   (let ((verbose-definition 
-           (if (string? diagram-definition)
-               (parse-terse-string diagram-definition)
-               diagram-definition)))
-     (map (lambda(item) 
-            (let ((code (car item)))
-              (cond
-                ((eq? code 'barre)
-                  (list-set! item 3
-                     (+ fret-offset (list-ref item 3)))
-                  item)
-                ((eq? code 'capo)
-                  (list-set! item 1
-                     (+ fret-offset (list-ref item 1)))
-                  item)
-                ((eq? code 'place-fret)
-                  (list-set! item 2
-                     (+ fret-offset (list-ref item 2)))
-                  item)
-                (else item))))
-            verbose-definition)))
-
+  (let ((verbose-definition
+         (if (string? diagram-definition)
+             (parse-terse-string diagram-definition)
+             diagram-definition)))
+    (map (lambda (item)
+           (let* ((code (car item))
+                  (nth (assq-ref '((barre . 3) (capo . 1) (place-fret . 2))
+                                 code)))
+             (if nth
+                 ;; offset nth element of item by offset-fret
+                 ;; without modifying the original list but
+                 ;; sharing its tail
+                 (let ((tail (list-tail item nth)))
+                   (append! (list-head item nth)
+                            (cons (+ (car tail) fret-offset)
+                                  (cdr tail))))
+                 item)))
+         verbose-definition)))