I'm considering replacing the register machine I wrote with an evaluator graph as a convenience for polyphony, but this would also open up the possibility of live editing patches. My register machine allows for no flow control, and each operation has at most two inputs and exactly one output. This is geometrically very convenient, so I'm thinking maybe something grid based to hopefully keep it simple.

Another thing that would be nice is being able to make patch-specific touch interfaces.

I'm thinking something like this for the visual language frontend. The nodes are grid aligned with space between for connections to run. Placing a new node in that space would insert a new row or column into the grid. Wire paths will probably be automatic, and the whole thing would ideally have a deterministic textual representation to make revision control easier.

Also important: graph cycles are allowed. If there's a feedback loop, the value is pulled from the previous frame's computation or is zero if there is no previous frame.

@aeva Adobe had a concept I really liked here which is a “poisoned” bit on values, so you can eg have out of range values still propagate through UI but have the downstream stuff turn red or w/e to indicate the problem