xmlToM21.py doesn't take offset into account when positioning spanner start/ends (SpannerAnchor is your friend) #1488
Description
music21 version
latest
Problem summary
See test_xmlToM21.py (testImportOttava):
# TODO(bug): first element should be ['C7', 'A6']
# not reading <offset>-4</offset>
The solution would be to see the offset, and put in a SpannerAnchor at the appropriately-offset offset instead of just whatever note is next in the MusicXML document.
Steps to reproduce
See testImportOttava.
I will be happy to work on this once I'm done with my Ottava (and other spanner) filling work.