Use constraint programming

[kinow]

Several workflow managers implement constraints in the workflows. For example:

A:success -> B, or A@midday -> B, or A & B -> C.

Q: could we borrow from constraint programming, or constraint logic programming, and other topics such as constraint optimization?

So instead of implementing the logic in the code, if we could use a well known, and well maintained library instead, that would make writing the workflow constraints simpler.

We could also gain from other features in these libraries, especially optimization techniques, creating space for interesting new ideas.