- /*
- * Choose a layout row: take the one following the last parsed
- * span's. If that doesn't exist, use the last parsed span's.
- * If there's no last parsed span, use the first row. Lastly,
- * if the last span was a horizontal line, use the same layout
- * (it doesn't "consume" the layout).
- *
- * In the end, this can be NULL!
- */