I don't think "live coding" music means that musicians would actually write code in front of an audience live -- it's not like musicians compose music in real time even without computers. In either case there is a lot of trial and error in getting things right that you wouldn't want an audience to see (or hear). I think "live coding" is just a fancy way of saying a programming experience with immediate feedback -- like a REPL but even more so.
There are many musicians who "build" music in live concerts with modular synthesizers (in newer times mostly with Eurorack modules). Since many decades! Without computers. With some experience they know how to handle their tools.
And with some experience a good live coder can do the same with his computer too.
I've seen performances where the live coding is just them building those same modular synths just digital. They start with a patch, and know what patch they need to end in. Everything between is up to them. Wish I had a better look at what they were doing.
