Helpers for building coroutines with serializable effect logs.

new/2 constructs a Coroutine with EffectLogger installed innermost, so every effect invocation across all handlers is captured in a JSON-serializable log. The returned value is a plain %Coroutine.Pending{} — run it, suspend it, resume it just like any other coroutine.

When the coroutine suspends, the log is accessible via get_log/1 (from the env in %Coroutine.ExternalSuspended{}). serialize/1 and deserialize/1 convert the log to/from JSON.

For resume: deserialize the log, build a new computation with EffectLogger.with_resume/4, install handlers, and wrap in a new Coroutine.

Usage

coroutine =
  SerializableCoroutine.new(my_comp, fn comp ->
    comp
    |> State.with_handler(0)
    |> Throw.with_handler()
    |> Yield.with_handler()
  end)

case Coroutine.run(coroutine) do
  %Coroutine.ExternalSuspended{value: yielded, env: env} = suspended ->
    log = SerializableCoroutine.get_log(suspended)
    json = SerializableCoroutine.serialize(log)
    # persist json...

    {:ok, log} = SerializableCoroutine.deserialize(json)
    # build a new coroutine for resume:
    resume_comp =
      my_comp
      |> EffectLogger.with_resume(log, user_input)
      |> then(&handlers_fun.(&1))

    Coroutine.run(Coroutine.new(resume_comp, Env.new()))

  %Coroutine.Completed{result: result} ->
    result
end

EffectLogger placement

EffectLogger.with_logging() is installed innermost (right after the computation, before handlers_fun), so its scope runs last and wraps all subsequently installed handlers. This ensures every effect invocation is captured.