Module echo 

Echo protocol — the reference extension (pure Protocol + its Interpret shell).

Demonstrates the model end to end: stateful (counts the messages seen), typed (its own Event/Effect), and effectful (echoes the payload back) — yet step is pure and the only IO (an overlay send) lives in the interpreter.

  S = ℕ
  step (Ctx n, Echoed{from, p}) = Transition (n+1) [Reply{to=from, p}]

Structs

Echo

Echo protocol: replies with the same payload and counts how many it has seen.

EchoShell

Echo’s interpreter: it owns no resources; a Reply is just an overlay send.

Echoed

A decoded echo message: who sent it and what bytes to echo back.

Enums

EchoEffect

Echo’s own effect: reply to to with payload over the overlay.

Constants

NAMESPACE

Namespace for the echo protocol.