pub fn make_variant_blocks(stream: &mut Stream) -> Result<()>Expand description
Moves each variant starting inside another’s span to start where that
one does, a hidden rest put before what it holds, as music21’s
makeVariantBlocks does.
music21 fails as soon as it has moved one, so this does too, the one moved.
§Errors
A variant starting inside another’s span, once it is moved.