Issue 3693: Let Percent_repeat_iterator be unfazed by Timing changes

There is still one shortcoming: the percent repeats will not contain any
material apart from the percent itself.  In particular, no Timing
changes will be repeated.  If there are meter changes or \partial
commands inside of percent repeats, they need to occur in parallel
passages outside of any percent repeat, if necessary in a separate
"timing track".

diff --git a/lily/percent-repeat-iterator.cc b/lily/percent-repeat-iterator.cc
index 00f21af4d6969f60f7190f4914c95f0683639b38..00d8eed88b0bb34edf26d20bdc60c660e8f9e9ef 100644 (file)
--- a/lily/percent-repeat-iterator.cc
+++ b/lily/percent-repeat-iterator.cc
@@ -32,31 +32,81 @@ public:
   Percent_repeat_iterator ();
 protected:
   virtual SCM get_music_list () const;
+  virtual void construct_children ();
+  virtual void next_element (bool);
+  virtual void derived_mark () const;
+private:
+  SCM child_list_;
+  int starting_bar_;
 };
 
 IMPLEMENT_CTOR_CALLBACK (Percent_repeat_iterator);
 
 Percent_repeat_iterator::Percent_repeat_iterator ()
+  : child_list_ (SCM_UNDEFINED), starting_bar_ (-1)
 {
 }
 
+void
+Percent_repeat_iterator::derived_mark () const
+{
+  scm_gc_mark (child_list_);
+}
+
+void
+Percent_repeat_iterator::construct_children ()
+{
+  Music *mus = get_music ();
+
+  Music *child = Repeated_music::body (mus);
+  child_list_ = scm_list_1 (child->self_scm ());
+
+  Sequential_iterator::construct_children ();
+
+  descend_to_bottom_context ();
+  if (!measure_position (get_outlet ()).main_part_)
+    starting_bar_ =
+      robust_scm2int (get_outlet ()->get_property ("internalBarNumber"), 0);
+}
+
 SCM
 Percent_repeat_iterator::get_music_list () const
 {
+  return child_list_;
+}
+
+// Arrive here when child processing has been completed.  At that
+// point of time, we can determine what kind of percent expression we
+// are dealing with and extend the child list just in time before the
+// next iterator is getting fetched.
+void
+Percent_repeat_iterator::next_element (bool side_effect)
+{
+  // Do nothing if we already did our processing here.
+  if (!scm_is_pair (child_list_))
+    {
+      Sequential_iterator::next_element (side_effect);
+      return;
+    }
+
   Music *mus = get_music ();
 
   Music *child = Repeated_music::body (mus);
   SCM length = child->get_length ().smobbed_copy ();
+
+  int current_bar = -1;
+  if (!measure_position (get_outlet ()).main_part_)
+    current_bar =
+      robust_scm2int (get_outlet ()->get_property ("internalBarNumber"), 0);
+
   SCM child_list = SCM_EOL;
-  Moment measure_len = measure_length (get_outlet ());
-  Moment music_len = robust_scm2moment (length, Moment (0));
 
   string event_type;
   SCM slash_count = SCM_EOL;
 
-  if (measure_len == music_len)
+  if (starting_bar_ >= 0 && current_bar == starting_bar_ + 1)
     event_type = "PercentEvent";
-  else if (measure_len * Moment (2) == music_len)
+  else if (starting_bar_ >=0 && current_bar == starting_bar_ + 2)
     event_type = "DoublePercentEvent";
   else
     {
@@ -80,7 +130,8 @@ Percent_repeat_iterator::get_music_list () const
       child_list = scm_cons (percent->unprotect (), child_list);
     }
 
-  child_list = scm_cons (child->self_scm (), child_list);
+  scm_set_cdr_x (child_list_, child_list);
+  child_list_ = SCM_EOL;
 
-  return child_list;
+  Sequential_iterator::next_element (side_effect);
 }