Imported Upstream version 2.19.45

[lilypond.git] / lily / part-combine-part-iterator.cc

diff --git a/lily/part-combine-part-iterator.cc b/lily/part-combine-part-iterator.cc
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+++ b/lily/part-combine-part-iterator.cc
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+/*
+  This file is part of LilyPond, the GNU music typesetter.
+
+  Copyright (C) 2015 Daniel Eble <dan@faithful.be>
+
+  LilyPond is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  LilyPond is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "change-sequence-iterator.hh"
+#include "context.hh"
+
+class Part_combine_part_iterator : public Change_sequence_iterator
+{
+public:
+  DECLARE_SCHEME_CALLBACK (constructor, ());
+  Part_combine_part_iterator () {}
+
+private:
+  virtual void change_to (const string &id);
+  Context *find_voice(const string &id);
+};
+
+void
+Part_combine_part_iterator::change_to (const string &id)
+{
+  Context *voice = find_voice (id);
+  if (voice)
+    substitute_outlet (get_outlet (), voice);
+  else
+    {
+      string s = "can not find Voice context: ";
+      s += id;
+      programming_error (s);
+    }
+}
+
+Context *
+Part_combine_part_iterator::find_voice (const string &id)
+{
+  // Find a Voice among the siblings of the current outlet.  (Well, this might
+  // also find a sibling's descendant, but that should not be a problem.)
+  Context *c = get_outlet ()->get_parent_context ();
+  if (c)
+    return find_context_below (c, ly_symbol2scm("Voice"), id);
+  programming_error ("no parent context");
+  return 0;
+}
+
+IMPLEMENT_CTOR_CALLBACK (Part_combine_part_iterator);