Maybe: Stateful Router

Status: Not implemented — noted for future consideration.

Problem

Current routed actions require the parent fragment’s model to hold child fragments’ models (e.g., model.file_list). The Router then needs to know which field name to use when dispatching to children and updating the parent model.

This couples the Router to the parent’s model structure.

Proposed Alternative

Make the Router stateful, holding child fragment models internally:

module ClassMethods
  def route(prefix, to:)
    # Router would also initialize and store child model
    child_model, init_command = to.const_get(:Init).()
    routed_models[prefix] = child_model
    routes[prefix] = to
  end
end

Pattern Symmetry

This mirrors the architecture at every level:

Pros

• Parent fragment doesn’t need nested model composition

• Router becomes a true “mini-runtime” for children

• Enables features like broadcasting resize events to all children

• Parent’s Update is simpler — just handles its own concerns

Cons

• Breaks from strict Elm pattern where parent Model contains child Models

• Router becomes stateful (but Runtime already is)

• Initialization order requires careful thought

• View needs a different way to access child models for rendering

Decision

Deferred. Current implementation requires parent to hold child models, which follows canonical Elm patterns. The stateful router approach is coherent but would be a significant architectural change.