From 8a07c9e873be8f6ba3f5476874735aefa817147c Mon Sep 17 00:00:00 2001
From: Graham Percival <graham@percival-music.ca>
Date: Fri, 10 Jun 2011 16:15:17 +0100
Subject: [PATCH] event-listener.ly: print explicit grace durations

---
 ly/event-listener.ly | 41 +++++++++++++++++++----------------------
 1 file changed, 19 insertions(+), 22 deletions(-)

diff --git a/ly/event-listener.ly b/ly/event-listener.ly
index 9089750263..7ba28602e6 100644
--- a/ly/event-listener.ly
+++ b/ly/event-listener.ly
@@ -60,28 +60,25 @@ name, it uses "unnamed-staff" for that part of the filename."
     (/ (ly:moment-main-numerator moment)
        (ly:moment-main-denominator moment))))
 
-#(define (adjust-for-grace moment)
-   "Adjusts any moment with a grace note by subtracting half of
-the grace note duration.  For example, an eighth note grace note
-which would otherwise occur at score time 0.5 will now occur at
-score time 0.375."
+#(define (moment-grace->string moment)
+   "Prints a moment without grace note(s) as a float such as
+0.25000.  Grace notes are written with the grace duration as a
+separate \"dashed\" number, i.e. 0.25000-0.12500.  This allows any
+program using the output of this function to interpret grace notes
+however they want (half duration, quarter duration?  before beat,
+after beat?  etc.)."
    (if
        (eq? 0 (ly:moment-grace-numerator moment))
-       moment
-       ;; get moment including grace note
-       ;; grace notes have a negative numerator, so add
-       (ly:moment-add moment
-                      ;; make the "grace duration" half as long
-                      (ly:moment-mul
-                       (ly:make-moment 1 2)
+       (ly:format "~a" (format-moment moment))
+       ;; grace notes have a negative numerator, so no "-" necessary
+       (ly:format
+         "~a~a"
+         (format-moment moment)
+         (format-moment
                        (ly:make-moment
                         (ly:moment-grace-numerator moment)
                         (ly:moment-grace-denominator moment))))))
 
-#(define (get-moment moment)
-   (format-moment (adjust-for-grace
-                   moment)))
-
 #(define (make-output-string-line engraver values)
    "Constructs a tab-separated string beginning with the
 score time (derived from the engraver) and then adding all the
@@ -90,12 +87,12 @@ values.  The string ends with a newline."
           (moment (ly:context-current-moment context)))
     (string-append
      (string-join
-      (map
-       (lambda (x) (ly:format "~a" x))
-        (append
-         (list (get-moment moment))
-          values))
-        "\t")
+       (append
+         (list (moment-grace->string moment))
+         (map
+             (lambda (x) (ly:format "~a" x))
+             values))
+       "\t")
      "\n")))
 
 
-- 
2.39.5