music-functions.scm: coding style improvement.

This commit makes the code cleaner and more concise,
by removing several duplicate parts.  Since I was the one
who last wrote this specific part, I'm feeling kind of
compelled to clean my own mess...

diff --git a/scm/music-functions.scm b/scm/music-functions.scm
index 95587b8670bf84ab44daf03b2ccfee66875f9936..78efe3e7460a6ba0eb33e49be80c638db3e00a66 100644 (file)
--- a/scm/music-functions.scm
+++ b/scm/music-functions.scm
@@ -889,7 +889,7 @@ Syntax:
     'Score))))
 
 (define (skip-as-needed music parser)
     'Score))))
 
 (define (skip-as-needed music parser)

- "Replace MUSIC by
+  "Replace MUSIC by

  << {  \\set skipTypesetting = ##f
  LENGTHOF(\\showFirstLength)
  \\set skipTypesetting = ##t
  << {  \\set skipTypesetting = ##f
  LENGTHOF(\\showFirstLength)
  \\set skipTypesetting = ##t


@@ -900,51 +900,56 @@ Syntax:
  When only showFirstLength is set,
  the 'length property of the music is
  overridden to speed up compiling."
  When only showFirstLength is set,
  the 'length property of the music is
  overridden to speed up compiling."

- (let*
-  ((show-last (ly:parser-lookup parser 'showLastLength))
-   (show-first (ly:parser-lookup parser 'showFirstLength)))
-  (cond
-
-   ;; both properties may be set.
-   ((and (ly:music? show-first) (ly:music? show-last))
-    (let*
-     ((orig-length (ly:music-length music))
-      (skip-length (ly:moment-sub orig-length (ly:music-length show-last)))
-      (begin-length (ly:music-length show-first)))
-     (make-simultaneous-music
-      (list
-       (make-sequential-music
-        (list
-         (skip-this skip-length)
-         ;; let's draw a separator between the beginning and the end
-         (context-spec-music (make-property-set 'whichBar "||")
-          'Timing)))
-       (unskip-this begin-length)
-       music))))
-
-   ;; we may only want to print the last length
-   ((ly:music? show-last)
-    (let*
-     ((orig-length (ly:music-length music))
-      (skip-length (ly:moment-sub orig-length (ly:music-length show-last))))
-     (make-simultaneous-music
-      (list
-       (skip-this skip-length)
-       music))))
-
-   ;; we may only want to print the beginning; in this case
-   ;; only the first length will be processed (much faster).
-   ((ly:music? show-first)
-    (let*
-     ((orig-length (ly:music-length music))
-      (begin-length (ly:music-length show-first)))
-     ;; the first length must not exceed the original length.
-     (if (ly:moment<? begin-length orig-length)
-      (set! (ly:music-property music 'length)
-       (ly:music-length show-first)))
-     music))
-
-   (else music))))
+  (let*
+      ((show-last (ly:parser-lookup parser 'showLastLength))
+       (show-first (ly:parser-lookup parser 'showFirstLength))
+       (show-last-length (if (ly:music? show-last)
+                             (ly:music-length show-last)
+                             #f))
+       (show-first-length (if (ly:music? show-first)
+                              (ly:music-length show-first)
+                              #f))
+       (orig-length (ly:music-length music)))
+
+    ;;FIXME: if using either showFirst- or showLastLength,
+    ;; make sure that skipBars is not set.
+
+    (cond
+
+     ;; both properties may be set.
+     ((and show-first-length show-last-length)
+      (let
+          ((skip-length (ly:moment-sub orig-length show-last-length)))
+        (make-simultaneous-music
+         (list
+          (make-sequential-music
+           (list
+            (skip-this skip-length)
+            ;; let's draw a separator between the beginning and the end
+            (context-spec-music (make-property-set 'whichBar "||")
+                                'Timing)))
+          (unskip-this show-first-length)
+          music))))
+
+     ;; we may only want to print the last length
+     (show-last-length
+      (let
+          ((skip-length (ly:moment-sub orig-length show-last-length)))
+        (make-simultaneous-music
+         (list
+          (skip-this skip-length)
+          music))))
+
+     ;; we may only want to print the beginning; in this case
+     ;; only the first length will be processed (much faster).
+     (show-first-length
+      ;; the first length must not exceed the original length.
+      (if (ly:moment<? show-first-length orig-length)
+          (set! (ly:music-property music 'length)
+                show-first-length))
+      music)
+
+     (else music))))

 
 
 (define-public toplevel-music-functions
 
 
 (define-public toplevel-music-functions