As a composer (of music for games?) I want to be able to represent an interactive musical performance in code

[ntoll]

As various expected events are encountered I want to be able to trigger audio events (this would be very useful for both gaming and live performances).

I also want to be able to track musical state, but as a musician I don't know about DAGs or state transition diagrams, so having something "built in" that's described/named using musical terms would be really helpful (e.g. "form", "key structure" etc). For instance, I might want to describe various musical sections (identified by letters), but it's only possible to transition from A->B, A->C, B->C, B->D, C->D, D->A, D->C and I want to express this in some way.