(control-points . ,ly:slur::calc-control-points)
(direction . ,ly:slur::calc-direction)
(springs-and-rods . ,ly:spanner::set-spacing-rods)
(control-points . ,ly:slur::calc-control-points)
(direction . ,ly:slur::calc-direction)
(springs-and-rods . ,ly:spanner::set-spacing-rods)