Networked Systems, System Trees, Dependency Chains

[marcgehman]

Hello, I've been experimenting with this library for a little while now, really impressed with all of the features and capabilities. It's also been a great resource for me to learn Nim's meta programming.

For our project, defining the order of execution is important. We need to construct networks, trees or chains of Systems. We could do this with groups, as discussed in https://github.com/rlipsc/polymorph/issues/11, however I feel this library could benefit from more expanded support.

Basically, the idea is to extend the concept of Groups to a more Network-based structure. There are methods which I have seen used in digital synthesizer applications to structure a network into a tree structure, resolving feedback cycles within the network. This, coupled with Polymorph's ECS model, could create a very general, powerful computational model.

We could build our own abstractions on top of Polymorph to achieve this, but it would be nicer if this were more natively integrated.

I was curious if you see this as a natural extension to the current Polymorph model, etc. Let me know your thoughts, would love to collaborate with you to implement something like this.

Thanks, Marc