I am working on a similar project called Harmony Explorer [0], which was spawned out of how challenging I find it to remember note names of chords and to figure out chord names when using a capo on guitar. Harmony Explorer also lets you listen to the chords, not just view them.

It is interesting to see how similar our approaches to note algebra is. While my project is written in Rust, it looks like we calculate note names in a very similar way [1].

I also really like the way you are handling accidentals - by storing accidentals including double-sharps and double-flats alongside the notes. I am using a global variable which picks between using sharps or flats when showing accidentals - works fine for now but definitely does not cover all use cases. I'll see if your approach can solve some of the problems I've encountered.

Thank you again for sharing, I feel like I learned many useful things from just a cursory glance at Kord. Likewise, I hope you find Harmony Explorer interesting!

[0] https://github.com/tiniuclx/harmony-explorer

[1] https://github.com/tiniuclx/harmony-explorer/blob/master/src...