* ly/music-functions-init.ly (parallelMusic): new music function for parallel

music entry.

* scm/define-music-properties.scm (all-music-properties): new 'void music property

* scm/music-functions.scm (ly:music-message): make public, to be
used in music function definitions

* scm/lily-library.scm (collect-music-for-book): discard music
when the 'void property is set.

diff --git a/ChangeLog b/ChangeLog
index 25e13176e8bcb5f007780eb218b3a31352405268..6e932bd1057569ba80d77a3b3822c4ef82ef95a9 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2006-01-22  Nicolas Sceaux  <nicolas.sceaux@free.fr>
+
+       * ly/music-functions-init.ly (parallelMusic): new music function for parallel
+       music entry.
+
+       * scm/define-music-properties.scm (all-music-properties): new 'void music property
+
+       * scm/music-functions.scm (ly:music-message): make public, to be
+       used in music function definitions
+
+       * scm/lily-library.scm (collect-music-for-book): discard music
+       when the 'void property is set.
+
 2006-01-22  Han-Wen Nienhuys  <hanwen@xs4all.nl>
 
        * lily/ttf.cc (LY_DEFINE): store name before destroying face.

diff --git a/ly/music-functions-init.ly b/ly/music-functions-init.ly
index 3ace0c203bc2c3dd6f45e3c948c3cd075063a991..8a8e24706d27d7adcfd930b838152464396bbf07 100644 (file)
--- a/ly/music-functions-init.ly
+++ b/ly/music-functions-init.ly
@@ -310,6 +310,90 @@ assertBeamSlope =
       (list chain-grob-member-functions `(,cons 0 0))
       (check-slope-callbacks comp))))))
     
-
-
-
+parallelMusic =
+#(def-music-function (parser location voice-ids music) (list? ly:music?)
+  "Define parallel music sequences, separated by '|' (bar check signs),
+and assign them to the identifiers provided in @var{voice-ids}.
+
+@var{voice-ids}: a list of music identifiers (symbols containing only letters)
+
+@var{music}: a music sequence, containing BarChecks as limiting expressions.
+
+Example:
+  \\parallelMusic #'(A B C) {
+    c c | d d | e e |
+    d d | e e | f f |
+  }
+<==>
+  A = { c c | d d | }
+  B = { d d | e e | }
+  C = { e e | f f | }
+"
+  (let* ((voices (apply circular-list (make-list (length voice-ids) (list))))
+         (current-voices voices)
+         (current-sequence (list)))
+    ;;
+    ;; utilities
+    (define (push-music m)
+      "Push the music expression into the current sequence"
+      (set! current-sequence (cons m current-sequence)))
+    (define (change-voice)
+      "Stores the previously built sequence into the current voice and
+       change to the following voice."
+      (list-set! current-voices 0 (cons (make-music 'SequentialMusic 
+                                         'elements (reverse! current-sequence))
+                                        (car current-voices)))
+      (set! current-sequence (list))
+      (set! current-voices (cdr current-voices)))
+    (define (bar-check? m)
+      "Checks whether m is a bar check."
+      (eq? (ly:music-property m 'name) 'BarCheck))
+    (define (music-origin music)
+      "Recursively search an origin location stored in music."
+      (cond ((null? music) #f)
+            ((not (null? (ly:music-property music 'origin)))
+             (ly:music-property music 'origin))
+            (else (or (music-origin (ly:music-property music 'element))
+                      (let ((origins (remove not (map music-origin 
+                                                      (ly:music-property music 'elements)))))
+                        (and (not (null? origins)) (car origins)))))))
+    ;;
+    ;; first, split the music and fill in voices
+    (map-in-order (lambda (m)
+                    (push-music m)
+                    (if (bar-check? m) (change-voice)))
+                  (ly:music-property music 'elements))
+    (if (not (null? current-sequence)) (change-voice))
+    ;; un-circularize `voices' and reorder the voices
+    (set! voices (map-in-order (lambda (dummy seqs)
+                                 (reverse! seqs))
+                               voice-ids voices))
+    ;;
+    ;; set origin location of each sequence in each voice
+    ;; for better type error tracking
+    (for-each (lambda (voice)
+                (for-each (lambda (seq)
+                            (set! (ly:music-property seq 'origin)
+                                  (or (music-origin seq) location)))
+                          voice))
+              voices)
+    ;;
+    ;; check sequence length
+    (apply for-each (lambda (. seqs)
+                      (let ((moment-reference (ly:music-length (car seqs))))
+                        (for-each (lambda (seq moment)
+                                    (if (not (equal? moment moment-reference))
+                                        (ly:music-message seq 
+                                         "Bars in parallel music don't have the same length")))
+                          seqs (map-in-order ly:music-length seqs))))
+           voices)
+   ;;
+   ;; bind voice identifiers to the voices
+   (map (lambda (voice-id voice)
+          (ly:parser-define! parser voice-id 
+                             (make-music 'SequentialMusic 
+                               'origin location
+                               'elements voice)))
+        voice-ids voices))
+ ;; Return an empty sequence. this function is actually a "void" function.
+ (make-music 'SequentialMusic 'void #t))
\ No newline at end of file

diff --git a/scm/define-music-properties.scm b/scm/define-music-properties.scm
index a9d2f399695fb3b29ddd25cfe38ec23f71f6f704..ebd8b9a0ff95f54e682d67dc068c10de09739059 100644 (file)
--- a/scm/define-music-properties.scm
+++ b/scm/define-music-properties.scm
@@ -108,6 +108,8 @@ e.g. @code{\\tag #'part ...} could tag a piece of music as only being active in
 engraver this music expression is processed.")
      (value ,scheme? "Assignment value for a
 translation property")
+     (void ,boolean? "If this property is #t, then the music expression is to be
+discarded by the toplevel music handler.")
      (what ,symbol? "What to change for auto-change. FIXME, naming")
      (part-combine-status ,symbol?
                          "Change to what kind of state? Options are

diff --git a/scm/lily-library.scm b/scm/lily-library.scm
index 5788f37a355e8440be2b0165a5e5123e92742503..057d6f88075064476ebf579d2a18e4ec573a84ff 100644 (file)
--- a/scm/lily-library.scm
+++ b/scm/lily-library.scm
@@ -75,7 +75,10 @@
   (ly:make-score music))
 
 (define-public (collect-music-for-book parser music)
-  (collect-scores-for-book parser (scorify-music music parser)))
+  ;; discard music if its 'void property is true.
+  (let ((void-music (ly:music-property music 'void)))
+    (if (or (null? void-music) (not void-music))
+        (collect-scores-for-book parser (scorify-music music parser)))))
 
 
 (define-public (print-book-with-defaults parser book)

diff --git a/scm/music-functions.scm b/scm/music-functions.scm
index 0074d3a1f6dd2b99846eab91ef52b517892e0d0d..3650dd0e8b0baf4f3cd4c260923a8dc358465f46 100644 (file)
--- a/scm/music-functions.scm
+++ b/scm/music-functions.scm
@@ -603,7 +603,7 @@ SkipEvent. Useful for extracting parts from crowded scores"
                 (equal? (ly:music-property x 'name) 'RequestChord))
               elts)))
 
-(define (ly:music-message music msg)
+(define-public (ly:music-message music msg)
   (let ((ip (ly:music-property music 'origin)))
     (if (ly:input-location? ip)
        (ly:input-message ip msg)