+ 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 "item.hh"
+#include "engraver.hh"
+#include "pointer-group-interface.hh"
+
+/**
+
+Make bars that span multiple "staves". Catch bars, and span a
+Span_bar over them if we find more than 2 bars. Vertical alignment
+of staves changes the appearance of spanbars. It is up to the
+aligner (Vertical_align_engraver, in this case, to add extra
+dependencies to the spanbars.
+*/
+class Span_bar_engraver : public Engraver