This engraver makes cross-staff barlines: It catches all normal bar lines, and draws a single span-bar across them.
This engraver creates the following grobs: SpanBar.
Span_bar_engraver is part of contexts: StaffGroup, GrandStaff, InnerStaffGroup and PianoStaff
This page is for LilyPond-2.0.0 (stable-branch).