This way, wouldn't have to reject tunes that the melody extraction doesn't currently support, enabling doing other things like working with the header data or viewing with abcjs, etc.. That is, we could wait to raise error until melody extraction is requested. Maybe use some cached properties. This should also make Tune init faster. Could also provide a simpler iterator that doesn't try to "play" the measures but just uses the note regex.

In #33 , a not-insignificant portion of The Session tunes (and 2 Norbeck tunes) are currently rejected (mostly because they have chords).

Pitch and such should have a method/property that returns a fancier text repr using unicode acc symbols and subscript octave numbers

https://en.wikipedia.org/wiki/Helmholtz_pitch_notation

Should maybe support converting pitches to (+ from?) strings of this format, as an alternative to SPN.

Pitch.from_name("Cb4").octave should be 4, according to this, but currently returns 3, though with UserWarning: computed pitch class value outside 0--11

For Note, when needing to pass key and duration, would be more convenient if those could be passed as strings. These can be unambiguously converted into Key and Fraction.

Probably some other cases too, but I imagine key would be the most helpful.

References:

• https://www.inspiredacoustics.com/en/MIDI_note_numbers_and_center_frequencies
• https://en.wikipedia.org/wiki/MIDI_tuning_standard

In particular, some error-raising code paths aren't tested currently.

• in Tune, Note._from_abc_match() should pass key=self.key in order to get the correct .value
• Note.to_abc() isn't properly key sensitive
• Some other Note.to_* methods seem to not always work properly if key used when constructing Note from abc

Use future annotations, and increase mypy strictness. Add pyupgrade --py38-plus to pre-commit.

Should examine, maybe do some perf comparisons.

seems like it will take a bit more than just changing the version number (tried current release and nb tune display was broken)