Nestup is an experimental markup language for musical rhythms. It's specifically designed to break away from a fixed musical grid.
The name is a contraction of nested tuplets, which are hard to program on a piano roll but easy to notate with Nestup.https://nestup.cutelab.nyc/
I'm still lurking, and still playing with music & live coding stuff. I've just been a bit busy lately. Part of my current effort is to try to make a combination note and text editor view for sheet music. I think there is interesting potential here to have a 2-way text->music representation that can be edited both as a simple stream of text tokens, and as visual notes.
... but for now I'm working on the complex issue of drawing musical notes and converting from a stream of tokens representing the music.
If you've seen my previous work, you'll know one of my interests is closing the gap between the live-coded music and the expectation of how it will sound.