expr

JAX visitors for core expression types.

Visitors: Constant, Parameter, NodeReference

Lowers the leaf value nodes that bottom out expression recursion. Constant bakes its value into the closure (squeezing singletons to true scalars); Parameter defers to a runtime lookup in the params dict, so parameters can be updated between SCP iterations without recompiling; NodeReference extracts a state/control value at a fixed trajectory node (the index is resolved at construction time), which is what lets cross-node constraints reach across the time grid.