Issue 3472: several fixes to input/regression/scheme-text-spanner.ly

* The file `input/regression/scheme-text-spanner.ly' assigns a constant
pair to the variable `event-drul' and subsequently attempts to modify
the pair.  This can lead to scheme-text-spanners not appearing when
requested in simultaneous contexts.  This patch corrects the faulty usage,
replacing `event-drul' with two variables `event-start' and `event-stop'.

* The variable `current-event' is not necessary, and has been removed.

* Tabs in the engraver definition have been replaced with spaces.

Signed-off-by: David Kastrup <dak@gnu.org>

diff --git a/input/regression/scheme-text-spanner.ly b/input/regression/scheme-text-spanner.ly
index 309fdd6926cbe9a0463f88b9646fa0528aa3a8fe..14e095e9549fea00fa45554183e33dd510e0b49b 100644 (file)
--- a/input/regression/scheme-text-spanner.ly
+++ b/input/regression/scheme-text-spanner.ly
@@ -113,59 +113,58 @@ schemeTextSpannerEngraver =
 #(lambda (context)
    (let ((span '())
          (finished '())
-         (current-event '())
-         (event-drul '(() . ())))
+         (event-start '())
+         (event-stop '()))
      (make-engraver
       (listeners ((scheme-text-span-event engraver event)
-                 (if (= START (ly:event-property event 'span-direction))
-                     (set-car! event-drul event)
-                     (set-cdr! event-drul event))))
+                  (if (= START (ly:event-property event 'span-direction))
+                      (set! event-start event)
+                      (set! event-stop event))))
       (acknowledgers ((note-column-interface engraver grob source-engraver)
-                     (if (ly:spanner? span)
-                         (begin
-                           (ly:pointer-group-interface::add-grob span 'note-columns grob)
-                           (add-bound-item span grob)))
-                     (if (ly:spanner? finished)
-                         (begin
-                           (ly:pointer-group-interface::add-grob finished 'note-columns grob)
-                           (add-bound-item finished grob)))))
+                      (if (ly:spanner? span)
+                          (begin
+                            (ly:pointer-group-interface::add-grob span 'note-columns grob)
+                            (add-bound-item span grob)))
+                      (if (ly:spanner? finished)
+                          (begin
+                            (ly:pointer-group-interface::add-grob finished 'note-columns grob)
+                            (add-bound-item finished grob)))))
       ((process-music trans)
-       (if (ly:stream-event? (cdr event-drul))
-          (if (null? span)
-              (ly:warning "You're trying to end a scheme text spanner but you haven't started one.")
-              (begin (set! finished span)
-                     (ly:engraver-announce-end-grob trans finished current-event)
-                     (set! span '())
-                     (set! current-event '())
-                     (set-cdr! event-drul '()))))
-       (if (ly:stream-event? (car event-drul))
-          (begin (set! current-event (car event-drul))
-                 (set! span (ly:engraver-make-grob trans 'SchemeTextSpanner current-event))
-                 (set-axis! span Y)
-                 (set-car! event-drul '()))))
+       (if (ly:stream-event? event-stop)
+           (if (null? span)
+               (ly:warning "You're trying to end a scheme text spanner but you haven't started one.")
+               (begin (set! finished span)
+                      (ly:engraver-announce-end-grob trans finished event-start)
+                      (set! span '())
+                      (set! event-stop '()))))
+       (if (ly:stream-event? event-start)
+           (begin (set! span (ly:engraver-make-grob trans 'SchemeTextSpanner event-start))
+                  (set-axis! span Y)
+                  (set! event-start '()))))
       ((stop-translation-timestep trans)
        (if (and (ly:spanner? span)
-               (null? (ly:spanner-bound span LEFT)))
-          (set! (ly:spanner-bound span LEFT)
-                (ly:context-property context 'currentMusicalColumn)))
+                (null? (ly:spanner-bound span LEFT)))
+           (set! (ly:spanner-bound span LEFT)
+                 (ly:context-property context 'currentMusicalColumn)))
        (if (ly:spanner? finished)
-          (begin
-            (if (null? (ly:spanner-bound finished RIGHT))
-                (set! (ly:spanner-bound finished RIGHT)
-                      (ly:context-property context 'currentMusicalColumn)))
-            (set! finished '())
-            (set! event-drul '(() . ())))))
+           (begin
+             (if (null? (ly:spanner-bound finished RIGHT))
+                 (set! (ly:spanner-bound finished RIGHT)
+                       (ly:context-property context 'currentMusicalColumn)))
+             (set! finished '())
+             (set! event-start '())
+             (set! event-stop '()))))
       ((finalize trans)
        (if (ly:spanner? finished)
-          (begin
-            (if (null? (ly:spanner-bound finished RIGHT))
-                (set! (ly:spanner-bound finished RIGHT)
-                      (ly:context-property context 'currentMusicalColumn)))
-            (set! finished '())))
+           (begin
+             (if (null? (ly:spanner-bound finished RIGHT))
+                 (set! (ly:spanner-bound finished RIGHT)
+                       (ly:context-property context 'currentMusicalColumn)))
+             (set! finished '())))
        (if (ly:spanner? span)
-          (begin
-            (ly:warning "I think there's a dangling scheme text spanner :-(")
-            (ly:grob-suicide! span)
+           (begin
+             (ly:warning "I think there's a dangling scheme text spanner :-(")
+             (ly:grob-suicide! span)
             (set! span '())))))))
 
 schemeTextSpannerStart =